feat: Implement ds-screencast engine, panel preview, and Waveshare ESP-NOW communication.

devices/panel-preview/index.html

@@ -973,10 +973,16 @@
     }
 
     // ── File loading ────────────────────────────────────
-    // Load from URL param
     const params = new URLSearchParams(location.search);
     const fileUrl = params.get('file');
-    if (fileUrl) {
+    const wsUrl = params.get('ws');  // e.g. ?ws=ws://localhost:9201
+
+    if (wsUrl) {
+      // ── WebSocket Binary Bridge Mode ─────────────────
+      // Connects to a relay that bridges UDP ↔ WebSocket.
+      // Receives binary signal frames from hub in real-time.
+      connectWebSocket(wsUrl);
+    } else if (fileUrl) {
       fetch(fileUrl)
         .then(r => r.json())
         .then(ir => { buildUI(ir); log(`Loaded from ${fileUrl}`); })
@@ -1003,13 +1009,126 @@
       }
     });
 
-    // Also try loading app.ir.json from same directory
+    // Auto-load app.ir.json (file mode fallback)
-    if (!fileUrl) {
+    if (!fileUrl && !wsUrl) {
       fetch('app.ir.json')
         .then(r => r.json())
         .then(ir => { buildUI(ir); log('Auto-loaded app.ir.json'); })
-        .catch(() => log('No app.ir.json found. Drag-drop an IR file or use ?file=URL'));
+        .catch(() => log('No app.ir.json found. Drag-drop an IR file or use ?file=URL or ?ws=ws://host:port'));
     }
+
+    // ── WebSocket Binary Bridge ──────────────────────────
+    // Frame types must match ds_espnow.h
+    const DS_NOW_SIG = 0x20;
+    const DS_NOW_SIG_BATCH = 0x21;
+    const DS_NOW_ACTION = 0x31;
+    const DS_NOW_PING = 0xFE;
+    const DS_NOW_PONG = 0xFD;
+    const DS_UDP_IR_PUSH = 0x40;
+
+    let ws = null;
+    let wsSeq = 0;
+
+    function connectWebSocket(url) {
+      log(`Connecting to ${url}...`, 'sig');
+      ws = new WebSocket(url);
+      ws.binaryType = 'arraybuffer';
+
+      ws.onopen = () => {
+        log('WebSocket connected — receiving live signals', 'sig');
+        document.getElementById('status').textContent = '🟢 Live';
+        document.querySelector('.dot').style.background = '#22c55e';
+      };
+
+      ws.onmessage = (event) => {
+        if (typeof event.data === 'string') {
+          // JSON message — treat as IR push
+          try {
+            const ir = JSON.parse(event.data);
+            buildUI(ir);
+            log('IR push received via WebSocket');
+          } catch (e) {
+            log(`WS JSON error: ${e}`);
+          }
+          return;
+        }
+
+        // Binary message
+        const buf = new DataView(event.data);
+        if (buf.byteLength < 1) return;
+        const type = buf.getUint8(0);
+
+        switch (type) {
+          case DS_NOW_SIG:
+            if (buf.byteLength >= 7) {
+              const sigId = buf.getUint16(1, true);
+              const value = buf.getInt32(3, true);
+              updateSignal(sigId, value);
+            }
+            break;
+
+          case DS_NOW_SIG_BATCH:
+            if (buf.byteLength >= 3) {
+              const count = buf.getUint8(1);
+              for (let i = 0; i < count; i++) {
+                const offset = 3 + i * 6;
+                if (offset + 6 > buf.byteLength) break;
+                const sigId = buf.getUint16(offset, true);
+                const value = buf.getInt32(offset + 2, true);
+                updateSignal(sigId, value);
+              }
+            }
+            break;
+
+          case DS_NOW_PING: {
+            // Respond with pong
+            const pong = new Uint8Array([DS_NOW_PONG, buf.getUint8(1)]);
+            ws.send(pong.buffer);
+            break;
+          }
+
+          case DS_UDP_IR_PUSH:
+            // Binary IR push: [magic:2][type][0][len:u16][json...]
+            if (buf.byteLength >= 6) {
+              const len = buf.getUint16(4, true);
+              const jsonBytes = new Uint8Array(event.data, 6, len);
+              const json = new TextDecoder().decode(jsonBytes);
+              try {
+                const ir = JSON.parse(json);
+                buildUI(ir);
+                log(`IR push received (${len} bytes)`);
+              } catch (e) {
+                log(`IR parse error: ${e}`);
+              }
+            }
+            break;
+
+          default:
+            log(`Unknown binary frame: 0x${type.toString(16)}`, 'evt');
+        }
+      };
+
+      ws.onclose = () => {
+        log('WebSocket disconnected — reconnecting in 3s...', 'evt');
+        document.getElementById('status').textContent = '🔴 Disconnected';
+        document.querySelector('.dot').style.background = '#ef4444';
+        setTimeout(() => connectWebSocket(url), 3000);
+      };
+
+      ws.onerror = (e) => {
+        log(`WebSocket error: ${e}`, 'evt');
+      };
+    }
+
+    // Send action event to hub (when button clicked in previewer)
+    function sendActionToHub(nodeId, actionType) {
+      if (!ws || ws.readyState !== WebSocket.OPEN) return;
+      const buf = new Uint8Array([DS_NOW_ACTION, nodeId, actionType, wsSeq++ & 0xFF]);
+      ws.send(buf.buffer);
+    }
+
+    // Expose globally so buildButton can call it
+    window.sendActionToHub = sendActionToHub;
   </script>
 </body>
 

devices/panel-preview/node_modules/.package-lock.json

@@ -0,0 +1,29 @@
+{
+  "name": "panel-preview",
+  "version": "1.0.0",
+  "lockfileVersion": 3,
+  "requires": true,
+  "packages": {
+    "node_modules/ws": {
+      "version": "8.19.0",
+      "resolved": "https://registry.npmjs.org/ws/-/ws-8.19.0.tgz",
+      "integrity": "sha512-blAT2mjOEIi0ZzruJfIhb3nps74PRWTCz1IjglWEEpQl5XS/UNama6u2/rjFkDDouqr4L67ry+1aGIALViWjDg==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=10.0.0"
+      },
+      "peerDependencies": {
+        "bufferutil": "^4.0.1",
+        "utf-8-validate": ">=5.0.2"
+      },
+      "peerDependenciesMeta": {
+        "bufferutil": {
+          "optional": true
+        },
+        "utf-8-validate": {
+          "optional": true
+        }
+      }
+    }
+  }
+}

devices/panel-preview/node_modules/ws/LICENSE

@@ -0,0 +1,20 @@
+Copyright (c) 2011 Einar Otto Stangvik <einaros@gmail.com>
+Copyright (c) 2013 Arnout Kazemier and contributors
+Copyright (c) 2016 Luigi Pinca and contributors
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

devices/panel-preview/node_modules/ws/README.md

@@ -0,0 +1,548 @@
+# ws: a Node.js WebSocket library
+
+[![Version npm](https://img.shields.io/npm/v/ws.svg?logo=npm)](https://www.npmjs.com/package/ws)
+[![CI](https://img.shields.io/github/actions/workflow/status/websockets/ws/ci.yml?branch=master&label=CI&logo=github)](https://github.com/websockets/ws/actions?query=workflow%3ACI+branch%3Amaster)
+[![Coverage Status](https://img.shields.io/coveralls/websockets/ws/master.svg?logo=coveralls)](https://coveralls.io/github/websockets/ws)
+
+ws is a simple to use, blazing fast, and thoroughly tested WebSocket client and
+server implementation.
+
+Passes the quite extensive Autobahn test suite: [server][server-report],
+[client][client-report].
+
+**Note**: This module does not work in the browser. The client in the docs is a
+reference to a backend with the role of a client in the WebSocket communication.
+Browser clients must use the native
+[`WebSocket`](https://developer.mozilla.org/en-US/docs/Web/API/WebSocket)
+object. To make the same code work seamlessly on Node.js and the browser, you
+can use one of the many wrappers available on npm, like
+[isomorphic-ws](https://github.com/heineiuo/isomorphic-ws).
+
+## Table of Contents
+
+- [Protocol support](#protocol-support)
+- [Installing](#installing)
+  - [Opt-in for performance](#opt-in-for-performance)
+    - [Legacy opt-in for performance](#legacy-opt-in-for-performance)
+- [API docs](#api-docs)
+- [WebSocket compression](#websocket-compression)
+- [Usage examples](#usage-examples)
+  - [Sending and receiving text data](#sending-and-receiving-text-data)
+  - [Sending binary data](#sending-binary-data)
+  - [Simple server](#simple-server)
+  - [External HTTP/S server](#external-https-server)
+  - [Multiple servers sharing a single HTTP/S server](#multiple-servers-sharing-a-single-https-server)
+  - [Client authentication](#client-authentication)
+  - [Server broadcast](#server-broadcast)
+  - [Round-trip time](#round-trip-time)
+  - [Use the Node.js streams API](#use-the-nodejs-streams-api)
+  - [Other examples](#other-examples)
+- [FAQ](#faq)
+  - [How to get the IP address of the client?](#how-to-get-the-ip-address-of-the-client)
+  - [How to detect and close broken connections?](#how-to-detect-and-close-broken-connections)
+  - [How to connect via a proxy?](#how-to-connect-via-a-proxy)
+- [Changelog](#changelog)
+- [License](#license)
+
+## Protocol support
+
+- **HyBi drafts 07-12** (Use the option `protocolVersion: 8`)
+- **HyBi drafts 13-17** (Current default, alternatively option
+  `protocolVersion: 13`)
+
+## Installing
+
+```
+npm install ws
+```
+
+### Opt-in for performance
+
+[bufferutil][] is an optional module that can be installed alongside the ws
+module:
+
+```
+npm install --save-optional bufferutil
+```
+
+This is a binary addon that improves the performance of certain operations such
+as masking and unmasking the data payload of the WebSocket frames. Prebuilt
+binaries are available for the most popular platforms, so you don't necessarily
+need to have a C++ compiler installed on your machine.
+
+To force ws to not use bufferutil, use the
+[`WS_NO_BUFFER_UTIL`](./doc/ws.md#ws_no_buffer_util) environment variable. This
+can be useful to enhance security in systems where a user can put a package in
+the package search path of an application of another user, due to how the
+Node.js resolver algorithm works.
+
+#### Legacy opt-in for performance
+
+If you are running on an old version of Node.js (prior to v18.14.0), ws also
+supports the [utf-8-validate][] module:
+
+```
+npm install --save-optional utf-8-validate
+```
+
+This contains a binary polyfill for [`buffer.isUtf8()`][].
+
+To force ws not to use utf-8-validate, use the
+[`WS_NO_UTF_8_VALIDATE`](./doc/ws.md#ws_no_utf_8_validate) environment variable.
+
+## API docs
+
+See [`/doc/ws.md`](./doc/ws.md) for Node.js-like documentation of ws classes and
+utility functions.
+
+## WebSocket compression
+
+ws supports the [permessage-deflate extension][permessage-deflate] which enables
+the client and server to negotiate a compression algorithm and its parameters,
+and then selectively apply it to the data payloads of each WebSocket message.
+
+The extension is disabled by default on the server and enabled by default on the
+client. It adds a significant overhead in terms of performance and memory
+consumption so we suggest to enable it only if it is really needed.
+
+Note that Node.js has a variety of issues with high-performance compression,
+where increased concurrency, especially on Linux, can lead to [catastrophic
+memory fragmentation][node-zlib-bug] and slow performance. If you intend to use
+permessage-deflate in production, it is worthwhile to set up a test
+representative of your workload and ensure Node.js/zlib will handle it with
+acceptable performance and memory usage.
+
+Tuning of permessage-deflate can be done via the options defined below. You can
+also use `zlibDeflateOptions` and `zlibInflateOptions`, which is passed directly
+into the creation of [raw deflate/inflate streams][node-zlib-deflaterawdocs].
+
+See [the docs][ws-server-options] for more options.
+
+```js
+import WebSocket, { WebSocketServer } from 'ws';
+
+const wss = new WebSocketServer({
+  port: 8080,
+  perMessageDeflate: {
+    zlibDeflateOptions: {
+      // See zlib defaults.
+      chunkSize: 1024,
+      memLevel: 7,
+      level: 3
+    },
+    zlibInflateOptions: {
+      chunkSize: 10 * 1024
+    },
+    // Other options settable:
+    clientNoContextTakeover: true, // Defaults to negotiated value.
+    serverNoContextTakeover: true, // Defaults to negotiated value.
+    serverMaxWindowBits: 10, // Defaults to negotiated value.
+    // Below options specified as default values.
+    concurrencyLimit: 10, // Limits zlib concurrency for perf.
+    threshold: 1024 // Size (in bytes) below which messages
+    // should not be compressed if context takeover is disabled.
+  }
+});
+```
+
+The client will only use the extension if it is supported and enabled on the
+server. To always disable the extension on the client, set the
+`perMessageDeflate` option to `false`.
+
+```js
+import WebSocket from 'ws';
+
+const ws = new WebSocket('ws://www.host.com/path', {
+  perMessageDeflate: false
+});
+```
+
+## Usage examples
+
+### Sending and receiving text data
+
+```js
+import WebSocket from 'ws';
+
+const ws = new WebSocket('ws://www.host.com/path');
+
+ws.on('error', console.error);
+
+ws.on('open', function open() {
+  ws.send('something');
+});
+
+ws.on('message', function message(data) {
+  console.log('received: %s', data);
+});
+```
+
+### Sending binary data
+
+```js
+import WebSocket from 'ws';
+
+const ws = new WebSocket('ws://www.host.com/path');
+
+ws.on('error', console.error);
+
+ws.on('open', function open() {
+  const array = new Float32Array(5);
+
+  for (var i = 0; i < array.length; ++i) {
+    array[i] = i / 2;
+  }
+
+  ws.send(array);
+});
+```
+
+### Simple server
+
+```js
+import { WebSocketServer } from 'ws';
+
+const wss = new WebSocketServer({ port: 8080 });
+
+wss.on('connection', function connection(ws) {
+  ws.on('error', console.error);
+
+  ws.on('message', function message(data) {
+    console.log('received: %s', data);
+  });
+
+  ws.send('something');
+});
+```
+
+### External HTTP/S server
+
+```js
+import { createServer } from 'https';
+import { readFileSync } from 'fs';
+import { WebSocketServer } from 'ws';
+
+const server = createServer({
+  cert: readFileSync('/path/to/cert.pem'),
+  key: readFileSync('/path/to/key.pem')
+});
+const wss = new WebSocketServer({ server });
+
+wss.on('connection', function connection(ws) {
+  ws.on('error', console.error);
+
+  ws.on('message', function message(data) {
+    console.log('received: %s', data);
+  });
+
+  ws.send('something');
+});
+
+server.listen(8080);
+```
+
+### Multiple servers sharing a single HTTP/S server
+
+```js
+import { createServer } from 'http';
+import { WebSocketServer } from 'ws';
+
+const server = createServer();
+const wss1 = new WebSocketServer({ noServer: true });
+const wss2 = new WebSocketServer({ noServer: true });
+
+wss1.on('connection', function connection(ws) {
+  ws.on('error', console.error);
+
+  // ...
+});
+
+wss2.on('connection', function connection(ws) {
+  ws.on('error', console.error);
+
+  // ...
+});
+
+server.on('upgrade', function upgrade(request, socket, head) {
+  const { pathname } = new URL(request.url, 'wss://base.url');
+
+  if (pathname === '/foo') {
+    wss1.handleUpgrade(request, socket, head, function done(ws) {
+      wss1.emit('connection', ws, request);
+    });
+  } else if (pathname === '/bar') {
+    wss2.handleUpgrade(request, socket, head, function done(ws) {
+      wss2.emit('connection', ws, request);
+    });
+  } else {
+    socket.destroy();
+  }
+});
+
+server.listen(8080);
+```
+
+### Client authentication
+
+```js
+import { createServer } from 'http';
+import { WebSocketServer } from 'ws';
+
+function onSocketError(err) {
+  console.error(err);
+}
+
+const server = createServer();
+const wss = new WebSocketServer({ noServer: true });
+
+wss.on('connection', function connection(ws, request, client) {
+  ws.on('error', console.error);
+
+  ws.on('message', function message(data) {
+    console.log(`Received message ${data} from user ${client}`);
+  });
+});
+
+server.on('upgrade', function upgrade(request, socket, head) {
+  socket.on('error', onSocketError);
+
+  // This function is not defined on purpose. Implement it with your own logic.
+  authenticate(request, function next(err, client) {
+    if (err || !client) {
+      socket.write('HTTP/1.1 401 Unauthorized\r\n\r\n');
+      socket.destroy();
+      return;
+    }
+
+    socket.removeListener('error', onSocketError);
+
+    wss.handleUpgrade(request, socket, head, function done(ws) {
+      wss.emit('connection', ws, request, client);
+    });
+  });
+});
+
+server.listen(8080);
+```
+
+Also see the provided [example][session-parse-example] using `express-session`.
+
+### Server broadcast
+
+A client WebSocket broadcasting to all connected WebSocket clients, including
+itself.
+
+```js
+import WebSocket, { WebSocketServer } from 'ws';
+
+const wss = new WebSocketServer({ port: 8080 });
+
+wss.on('connection', function connection(ws) {
+  ws.on('error', console.error);
+
+  ws.on('message', function message(data, isBinary) {
+    wss.clients.forEach(function each(client) {
+      if (client.readyState === WebSocket.OPEN) {
+        client.send(data, { binary: isBinary });
+      }
+    });
+  });
+});
+```
+
+A client WebSocket broadcasting to every other connected WebSocket clients,
+excluding itself.
+
+```js
+import WebSocket, { WebSocketServer } from 'ws';
+
+const wss = new WebSocketServer({ port: 8080 });
+
+wss.on('connection', function connection(ws) {
+  ws.on('error', console.error);
+
+  ws.on('message', function message(data, isBinary) {
+    wss.clients.forEach(function each(client) {
+      if (client !== ws && client.readyState === WebSocket.OPEN) {
+        client.send(data, { binary: isBinary });
+      }
+    });
+  });
+});
+```
+
+### Round-trip time
+
+```js
+import WebSocket from 'ws';
+
+const ws = new WebSocket('wss://websocket-echo.com/');
+
+ws.on('error', console.error);
+
+ws.on('open', function open() {
+  console.log('connected');
+  ws.send(Date.now());
+});
+
+ws.on('close', function close() {
+  console.log('disconnected');
+});
+
+ws.on('message', function message(data) {
+  console.log(`Round-trip time: ${Date.now() - data} ms`);
+
+  setTimeout(function timeout() {
+    ws.send(Date.now());
+  }, 500);
+});
+```
+
+### Use the Node.js streams API
+
+```js
+import WebSocket, { createWebSocketStream } from 'ws';
+
+const ws = new WebSocket('wss://websocket-echo.com/');
+
+const duplex = createWebSocketStream(ws, { encoding: 'utf8' });
+
+duplex.on('error', console.error);
+
+duplex.pipe(process.stdout);
+process.stdin.pipe(duplex);
+```
+
+### Other examples
+
+For a full example with a browser client communicating with a ws server, see the
+examples folder.
+
+Otherwise, see the test cases.
+
+## FAQ
+
+### How to get the IP address of the client?
+
+The remote IP address can be obtained from the raw socket.
+
+```js
+import { WebSocketServer } from 'ws';
+
+const wss = new WebSocketServer({ port: 8080 });
+
+wss.on('connection', function connection(ws, req) {
+  const ip = req.socket.remoteAddress;
+
+  ws.on('error', console.error);
+});
+```
+
+When the server runs behind a proxy like NGINX, the de-facto standard is to use
+the `X-Forwarded-For` header.
+
+```js
+wss.on('connection', function connection(ws, req) {
+  const ip = req.headers['x-forwarded-for'].split(',')[0].trim();
+
+  ws.on('error', console.error);
+});
+```
+
+### How to detect and close broken connections?
+
+Sometimes, the link between the server and the client can be interrupted in a
+way that keeps both the server and the client unaware of the broken state of the
+connection (e.g. when pulling the cord).
+
+In these cases, ping messages can be used as a means to verify that the remote
+endpoint is still responsive.
+
+```js
+import { WebSocketServer } from 'ws';
+
+function heartbeat() {
+  this.isAlive = true;
+}
+
+const wss = new WebSocketServer({ port: 8080 });
+
+wss.on('connection', function connection(ws) {
+  ws.isAlive = true;
+  ws.on('error', console.error);
+  ws.on('pong', heartbeat);
+});
+
+const interval = setInterval(function ping() {
+  wss.clients.forEach(function each(ws) {
+    if (ws.isAlive === false) return ws.terminate();
+
+    ws.isAlive = false;
+    ws.ping();
+  });
+}, 30000);
+
+wss.on('close', function close() {
+  clearInterval(interval);
+});
+```
+
+Pong messages are automatically sent in response to ping messages as required by
+the spec.
+
+Just like the server example above, your clients might as well lose connection
+without knowing it. You might want to add a ping listener on your clients to
+prevent that. A simple implementation would be:
+
+```js
+import WebSocket from 'ws';
+
+function heartbeat() {
+  clearTimeout(this.pingTimeout);
+
+  // Use `WebSocket#terminate()`, which immediately destroys the connection,
+  // instead of `WebSocket#close()`, which waits for the close timer.
+  // Delay should be equal to the interval at which your server
+  // sends out pings plus a conservative assumption of the latency.
+  this.pingTimeout = setTimeout(() => {
+    this.terminate();
+  }, 30000 + 1000);
+}
+
+const client = new WebSocket('wss://websocket-echo.com/');
+
+client.on('error', console.error);
+client.on('open', heartbeat);
+client.on('ping', heartbeat);
+client.on('close', function clear() {
+  clearTimeout(this.pingTimeout);
+});
+```
+
+### How to connect via a proxy?
+
+Use a custom `http.Agent` implementation like [https-proxy-agent][] or
+[socks-proxy-agent][].
+
+## Changelog
+
+We're using the GitHub [releases][changelog] for changelog entries.
+
+## License
+
+[MIT](LICENSE)
+
+[`buffer.isutf8()`]: https://nodejs.org/api/buffer.html#bufferisutf8input
+[bufferutil]: https://github.com/websockets/bufferutil
+[changelog]: https://github.com/websockets/ws/releases
+[client-report]: http://websockets.github.io/ws/autobahn/clients/
+[https-proxy-agent]: https://github.com/TooTallNate/node-https-proxy-agent
+[node-zlib-bug]: https://github.com/nodejs/node/issues/8871
+[node-zlib-deflaterawdocs]:
+  https://nodejs.org/api/zlib.html#zlib_zlib_createdeflateraw_options
+[permessage-deflate]: https://tools.ietf.org/html/rfc7692
+[server-report]: http://websockets.github.io/ws/autobahn/servers/
+[session-parse-example]: ./examples/express-session-parse
+[socks-proxy-agent]: https://github.com/TooTallNate/node-socks-proxy-agent
+[utf-8-validate]: https://github.com/websockets/utf-8-validate
+[ws-server-options]: ./doc/ws.md#new-websocketserveroptions-callback

devices/panel-preview/node_modules/ws/browser.js

@@ -0,0 +1,8 @@
+'use strict';
+
+module.exports = function () {
+  throw new Error(
+    'ws does not work in the browser. Browser clients must use the native ' +
+      'WebSocket object'
+  );
+};

devices/panel-preview/node_modules/ws/index.js

@@ -0,0 +1,13 @@
+'use strict';
+
+const WebSocket = require('./lib/websocket');
+
+WebSocket.createWebSocketStream = require('./lib/stream');
+WebSocket.Server = require('./lib/websocket-server');
+WebSocket.Receiver = require('./lib/receiver');
+WebSocket.Sender = require('./lib/sender');
+
+WebSocket.WebSocket = WebSocket;
+WebSocket.WebSocketServer = WebSocket.Server;
+
+module.exports = WebSocket;

devices/panel-preview/node_modules/ws/lib/buffer-util.js

@@ -0,0 +1,131 @@
+'use strict';
+
+const { EMPTY_BUFFER } = require('./constants');
+
+const FastBuffer = Buffer[Symbol.species];
+
+/**
+ * Merges an array of buffers into a new buffer.
+ *
+ * @param {Buffer[]} list The array of buffers to concat
+ * @param {Number} totalLength The total length of buffers in the list
+ * @return {Buffer} The resulting buffer
+ * @public
+ */
+function concat(list, totalLength) {
+  if (list.length === 0) return EMPTY_BUFFER;
+  if (list.length === 1) return list[0];
+
+  const target = Buffer.allocUnsafe(totalLength);
+  let offset = 0;
+
+  for (let i = 0; i < list.length; i++) {
+    const buf = list[i];
+    target.set(buf, offset);
+    offset += buf.length;
+  }
+
+  if (offset < totalLength) {
+    return new FastBuffer(target.buffer, target.byteOffset, offset);
+  }
+
+  return target;
+}
+
+/**
+ * Masks a buffer using the given mask.
+ *
+ * @param {Buffer} source The buffer to mask
+ * @param {Buffer} mask The mask to use
+ * @param {Buffer} output The buffer where to store the result
+ * @param {Number} offset The offset at which to start writing
+ * @param {Number} length The number of bytes to mask.
+ * @public
+ */
+function _mask(source, mask, output, offset, length) {
+  for (let i = 0; i < length; i++) {
+    output[offset + i] = source[i] ^ mask[i & 3];
+  }
+}
+
+/**
+ * Unmasks a buffer using the given mask.
+ *
+ * @param {Buffer} buffer The buffer to unmask
+ * @param {Buffer} mask The mask to use
+ * @public
+ */
+function _unmask(buffer, mask) {
+  for (let i = 0; i < buffer.length; i++) {
+    buffer[i] ^= mask[i & 3];
+  }
+}
+
+/**
+ * Converts a buffer to an `ArrayBuffer`.
+ *
+ * @param {Buffer} buf The buffer to convert
+ * @return {ArrayBuffer} Converted buffer
+ * @public
+ */
+function toArrayBuffer(buf) {
+  if (buf.length === buf.buffer.byteLength) {
+    return buf.buffer;
+  }
+
+  return buf.buffer.slice(buf.byteOffset, buf.byteOffset + buf.length);
+}
+
+/**
+ * Converts `data` to a `Buffer`.
+ *
+ * @param {*} data The data to convert
+ * @return {Buffer} The buffer
+ * @throws {TypeError}
+ * @public
+ */
+function toBuffer(data) {
+  toBuffer.readOnly = true;
+
+  if (Buffer.isBuffer(data)) return data;
+
+  let buf;
+
+  if (data instanceof ArrayBuffer) {
+    buf = new FastBuffer(data);
+  } else if (ArrayBuffer.isView(data)) {
+    buf = new FastBuffer(data.buffer, data.byteOffset, data.byteLength);
+  } else {
+    buf = Buffer.from(data);
+    toBuffer.readOnly = false;
+  }
+
+  return buf;
+}
+
+module.exports = {
+  concat,
+  mask: _mask,
+  toArrayBuffer,
+  toBuffer,
+  unmask: _unmask
+};
+
+/* istanbul ignore else  */
+if (!process.env.WS_NO_BUFFER_UTIL) {
+  try {
+    const bufferUtil = require('bufferutil');
+
+    module.exports.mask = function (source, mask, output, offset, length) {
+      if (length < 48) _mask(source, mask, output, offset, length);
+      else bufferUtil.mask(source, mask, output, offset, length);
+    };
+
+    module.exports.unmask = function (buffer, mask) {
+      if (buffer.length < 32) _unmask(buffer, mask);
+      else bufferUtil.unmask(buffer, mask);
+    };
+  } catch (e) {
+    // Continue regardless of the error.
+  }
+}

devices/panel-preview/node_modules/ws/lib/constants.js

@@ -0,0 +1,19 @@
+'use strict';
+
+const BINARY_TYPES = ['nodebuffer', 'arraybuffer', 'fragments'];
+const hasBlob = typeof Blob !== 'undefined';
+
+if (hasBlob) BINARY_TYPES.push('blob');
+
+module.exports = {
+  BINARY_TYPES,
+  CLOSE_TIMEOUT: 30000,
+  EMPTY_BUFFER: Buffer.alloc(0),
+  GUID: '258EAFA5-E914-47DA-95CA-C5AB0DC85B11',
+  hasBlob,
+  kForOnEventAttribute: Symbol('kIsForOnEventAttribute'),
+  kListener: Symbol('kListener'),
+  kStatusCode: Symbol('status-code'),
+  kWebSocket: Symbol('websocket'),
+  NOOP: () => {}
+};

devices/panel-preview/node_modules/ws/lib/event-target.js

@@ -0,0 +1,292 @@
+'use strict';
+
+const { kForOnEventAttribute, kListener } = require('./constants');
+
+const kCode = Symbol('kCode');
+const kData = Symbol('kData');
+const kError = Symbol('kError');
+const kMessage = Symbol('kMessage');
+const kReason = Symbol('kReason');
+const kTarget = Symbol('kTarget');
+const kType = Symbol('kType');
+const kWasClean = Symbol('kWasClean');
+
+/**
+ * Class representing an event.
+ */
+class Event {
+  /**
+   * Create a new `Event`.
+   *
+   * @param {String} type The name of the event
+   * @throws {TypeError} If the `type` argument is not specified
+   */
+  constructor(type) {
+    this[kTarget] = null;
+    this[kType] = type;
+  }
+
+  /**
+   * @type {*}
+   */
+  get target() {
+    return this[kTarget];
+  }
+
+  /**
+   * @type {String}
+   */
+  get type() {
+    return this[kType];
+  }
+}
+
+Object.defineProperty(Event.prototype, 'target', { enumerable: true });
+Object.defineProperty(Event.prototype, 'type', { enumerable: true });
+
+/**
+ * Class representing a close event.
+ *
+ * @extends Event
+ */
+class CloseEvent extends Event {
+  /**
+   * Create a new `CloseEvent`.
+   *
+   * @param {String} type The name of the event
+   * @param {Object} [options] A dictionary object that allows for setting
+   *     attributes via object members of the same name
+   * @param {Number} [options.code=0] The status code explaining why the
+   *     connection was closed
+   * @param {String} [options.reason=''] A human-readable string explaining why
+   *     the connection was closed
+   * @param {Boolean} [options.wasClean=false] Indicates whether or not the
+   *     connection was cleanly closed
+   */
+  constructor(type, options = {}) {
+    super(type);
+
+    this[kCode] = options.code === undefined ? 0 : options.code;
+    this[kReason] = options.reason === undefined ? '' : options.reason;
+    this[kWasClean] = options.wasClean === undefined ? false : options.wasClean;
+  }
+
+  /**
+   * @type {Number}
+   */
+  get code() {
+    return this[kCode];
+  }
+
+  /**
+   * @type {String}
+   */
+  get reason() {
+    return this[kReason];
+  }
+
+  /**
+   * @type {Boolean}
+   */
+  get wasClean() {
+    return this[kWasClean];
+  }
+}
+
+Object.defineProperty(CloseEvent.prototype, 'code', { enumerable: true });
+Object.defineProperty(CloseEvent.prototype, 'reason', { enumerable: true });
+Object.defineProperty(CloseEvent.prototype, 'wasClean', { enumerable: true });
+
+/**
+ * Class representing an error event.
+ *
+ * @extends Event
+ */
+class ErrorEvent extends Event {
+  /**
+   * Create a new `ErrorEvent`.
+   *
+   * @param {String} type The name of the event
+   * @param {Object} [options] A dictionary object that allows for setting
+   *     attributes via object members of the same name
+   * @param {*} [options.error=null] The error that generated this event
+   * @param {String} [options.message=''] The error message
+   */
+  constructor(type, options = {}) {
+    super(type);
+
+    this[kError] = options.error === undefined ? null : options.error;
+    this[kMessage] = options.message === undefined ? '' : options.message;
+  }
+
+  /**
+   * @type {*}
+   */
+  get error() {
+    return this[kError];
+  }
+
+  /**
+   * @type {String}
+   */
+  get message() {
+    return this[kMessage];
+  }
+}
+
+Object.defineProperty(ErrorEvent.prototype, 'error', { enumerable: true });
+Object.defineProperty(ErrorEvent.prototype, 'message', { enumerable: true });
+
+/**
+ * Class representing a message event.
+ *
+ * @extends Event
+ */
+class MessageEvent extends Event {
+  /**
+   * Create a new `MessageEvent`.
+   *
+   * @param {String} type The name of the event
+   * @param {Object} [options] A dictionary object that allows for setting
+   *     attributes via object members of the same name
+   * @param {*} [options.data=null] The message content
+   */
+  constructor(type, options = {}) {
+    super(type);
+
+    this[kData] = options.data === undefined ? null : options.data;
+  }
+
+  /**
+   * @type {*}
+   */
+  get data() {
+    return this[kData];
+  }
+}
+
+Object.defineProperty(MessageEvent.prototype, 'data', { enumerable: true });
+
+/**
+ * This provides methods for emulating the `EventTarget` interface. It's not
+ * meant to be used directly.
+ *
+ * @mixin
+ */
+const EventTarget = {
+  /**
+   * Register an event listener.
+   *
+   * @param {String} type A string representing the event type to listen for
+   * @param {(Function|Object)} handler The listener to add
+   * @param {Object} [options] An options object specifies characteristics about
+   *     the event listener
+   * @param {Boolean} [options.once=false] A `Boolean` indicating that the
+   *     listener should be invoked at most once after being added. If `true`,
+   *     the listener would be automatically removed when invoked.
+   * @public
+   */
+  addEventListener(type, handler, options = {}) {
+    for (const listener of this.listeners(type)) {
+      if (
+        !options[kForOnEventAttribute] &&
+        listener[kListener] === handler &&
+        !listener[kForOnEventAttribute]
+      ) {
+        return;
+      }
+    }
+
+    let wrapper;
+
+    if (type === 'message') {
+      wrapper = function onMessage(data, isBinary) {
+        const event = new MessageEvent('message', {
+          data: isBinary ? data : data.toString()
+        });
+
+        event[kTarget] = this;
+        callListener(handler, this, event);
+      };
+    } else if (type === 'close') {
+      wrapper = function onClose(code, message) {
+        const event = new CloseEvent('close', {
+          code,
+          reason: message.toString(),
+          wasClean: this._closeFrameReceived && this._closeFrameSent
+        });
+
+        event[kTarget] = this;
+        callListener(handler, this, event);
+      };
+    } else if (type === 'error') {
+      wrapper = function onError(error) {
+        const event = new ErrorEvent('error', {
+          error,
+          message: error.message
+        });
+
+        event[kTarget] = this;
+        callListener(handler, this, event);
+      };
+    } else if (type === 'open') {
+      wrapper = function onOpen() {
+        const event = new Event('open');
+
+        event[kTarget] = this;
+        callListener(handler, this, event);
+      };
+    } else {
+      return;
+    }
+
+    wrapper[kForOnEventAttribute] = !!options[kForOnEventAttribute];
+    wrapper[kListener] = handler;
+
+    if (options.once) {
+      this.once(type, wrapper);
+    } else {
+      this.on(type, wrapper);
+    }
+  },
+
+  /**
+   * Remove an event listener.
+   *
+   * @param {String} type A string representing the event type to remove
+   * @param {(Function|Object)} handler The listener to remove
+   * @public
+   */
+  removeEventListener(type, handler) {
+    for (const listener of this.listeners(type)) {
+      if (listener[kListener] === handler && !listener[kForOnEventAttribute]) {
+        this.removeListener(type, listener);
+        break;
+      }
+    }
+  }
+};
+
+module.exports = {
+  CloseEvent,
+  ErrorEvent,
+  Event,
+  EventTarget,
+  MessageEvent
+};
+
+/**
+ * Call an event listener
+ *
+ * @param {(Function|Object)} listener The listener to call
+ * @param {*} thisArg The value to use as `this`` when calling the listener
+ * @param {Event} event The event to pass to the listener
+ * @private
+ */
+function callListener(listener, thisArg, event) {
+  if (typeof listener === 'object' && listener.handleEvent) {
+    listener.handleEvent.call(listener, event);
+  } else {
+    listener.call(thisArg, event);
+  }
+}

devices/panel-preview/node_modules/ws/lib/extension.js

@@ -0,0 +1,203 @@
+'use strict';
+
+const { tokenChars } = require('./validation');
+
+/**
+ * Adds an offer to the map of extension offers or a parameter to the map of
+ * parameters.
+ *
+ * @param {Object} dest The map of extension offers or parameters
+ * @param {String} name The extension or parameter name
+ * @param {(Object|Boolean|String)} elem The extension parameters or the
+ *     parameter value
+ * @private
+ */
+function push(dest, name, elem) {
+  if (dest[name] === undefined) dest[name] = [elem];
+  else dest[name].push(elem);
+}
+
+/**
+ * Parses the `Sec-WebSocket-Extensions` header into an object.
+ *
+ * @param {String} header The field value of the header
+ * @return {Object} The parsed object
+ * @public
+ */
+function parse(header) {
+  const offers = Object.create(null);
+  let params = Object.create(null);
+  let mustUnescape = false;
+  let isEscaping = false;
+  let inQuotes = false;
+  let extensionName;
+  let paramName;
+  let start = -1;
+  let code = -1;
+  let end = -1;
+  let i = 0;
+
+  for (; i < header.length; i++) {
+    code = header.charCodeAt(i);
+
+    if (extensionName === undefined) {
+      if (end === -1 && tokenChars[code] === 1) {
+        if (start === -1) start = i;
+      } else if (
+        i !== 0 &&
+        (code === 0x20 /* ' ' */ || code === 0x09) /* '\t' */
+      ) {
+        if (end === -1 && start !== -1) end = i;
+      } else if (code === 0x3b /* ';' */ || code === 0x2c /* ',' */) {
+        if (start === -1) {
+          throw new SyntaxError(`Unexpected character at index ${i}`);
+        }
+
+        if (end === -1) end = i;
+        const name = header.slice(start, end);
+        if (code === 0x2c) {
+          push(offers, name, params);
+          params = Object.create(null);
+        } else {
+          extensionName = name;
+        }
+
+        start = end = -1;
+      } else {
+        throw new SyntaxError(`Unexpected character at index ${i}`);
+      }
+    } else if (paramName === undefined) {
+      if (end === -1 && tokenChars[code] === 1) {
+        if (start === -1) start = i;
+      } else if (code === 0x20 || code === 0x09) {
+        if (end === -1 && start !== -1) end = i;
+      } else if (code === 0x3b || code === 0x2c) {
+        if (start === -1) {
+          throw new SyntaxError(`Unexpected character at index ${i}`);
+        }
+
+        if (end === -1) end = i;
+        push(params, header.slice(start, end), true);
+        if (code === 0x2c) {
+          push(offers, extensionName, params);
+          params = Object.create(null);
+          extensionName = undefined;
+        }
+
+        start = end = -1;
+      } else if (code === 0x3d /* '=' */ && start !== -1 && end === -1) {
+        paramName = header.slice(start, i);
+        start = end = -1;
+      } else {
+        throw new SyntaxError(`Unexpected character at index ${i}`);
+      }
+    } else {
+      //
+      // The value of a quoted-string after unescaping must conform to the
+      // token ABNF, so only token characters are valid.
+      // Ref: https://tools.ietf.org/html/rfc6455#section-9.1
+      //
+      if (isEscaping) {
+        if (tokenChars[code] !== 1) {
+          throw new SyntaxError(`Unexpected character at index ${i}`);
+        }
+        if (start === -1) start = i;
+        else if (!mustUnescape) mustUnescape = true;
+        isEscaping = false;
+      } else if (inQuotes) {
+        if (tokenChars[code] === 1) {
+          if (start === -1) start = i;
+        } else if (code === 0x22 /* '"' */ && start !== -1) {
+          inQuotes = false;
+          end = i;
+        } else if (code === 0x5c /* '\' */) {
+          isEscaping = true;
+        } else {
+          throw new SyntaxError(`Unexpected character at index ${i}`);
+        }
+      } else if (code === 0x22 && header.charCodeAt(i - 1) === 0x3d) {
+        inQuotes = true;
+      } else if (end === -1 && tokenChars[code] === 1) {
+        if (start === -1) start = i;
+      } else if (start !== -1 && (code === 0x20 || code === 0x09)) {
+        if (end === -1) end = i;
+      } else if (code === 0x3b || code === 0x2c) {
+        if (start === -1) {
+          throw new SyntaxError(`Unexpected character at index ${i}`);
+        }
+
+        if (end === -1) end = i;
+        let value = header.slice(start, end);
+        if (mustUnescape) {
+          value = value.replace(/\\/g, '');
+          mustUnescape = false;
+        }
+        push(params, paramName, value);
+        if (code === 0x2c) {
+          push(offers, extensionName, params);
+          params = Object.create(null);
+          extensionName = undefined;
+        }
+
+        paramName = undefined;
+        start = end = -1;
+      } else {
+        throw new SyntaxError(`Unexpected character at index ${i}`);
+      }
+    }
+  }
+
+  if (start === -1 || inQuotes || code === 0x20 || code === 0x09) {
+    throw new SyntaxError('Unexpected end of input');
+  }
+
+  if (end === -1) end = i;
+  const token = header.slice(start, end);
+  if (extensionName === undefined) {
+    push(offers, token, params);
+  } else {
+    if (paramName === undefined) {
+      push(params, token, true);
+    } else if (mustUnescape) {
+      push(params, paramName, token.replace(/\\/g, ''));
+    } else {
+      push(params, paramName, token);
+    }
+    push(offers, extensionName, params);
+  }
+
+  return offers;
+}
+
+/**
+ * Builds the `Sec-WebSocket-Extensions` header field value.
+ *
+ * @param {Object} extensions The map of extensions and parameters to format
+ * @return {String} A string representing the given object
+ * @public
+ */
+function format(extensions) {
+  return Object.keys(extensions)
+    .map((extension) => {
+      let configurations = extensions[extension];
+      if (!Array.isArray(configurations)) configurations = [configurations];
+      return configurations
+        .map((params) => {
+          return [extension]
+            .concat(
+              Object.keys(params).map((k) => {
+                let values = params[k];
+                if (!Array.isArray(values)) values = [values];
+                return values
+                  .map((v) => (v === true ? k : `${k}=${v}`))
+                  .join('; ');
+              })
+            )
+            .join('; ');
+        })
+        .join(', ');
+    })
+    .join(', ');
+}
+
+module.exports = { format, parse };

devices/panel-preview/node_modules/ws/lib/limiter.js

@@ -0,0 +1,55 @@
+'use strict';
+
+const kDone = Symbol('kDone');
+const kRun = Symbol('kRun');
+
+/**
+ * A very simple job queue with adjustable concurrency. Adapted from
+ * https://github.com/STRML/async-limiter
+ */
+class Limiter {
+  /**
+   * Creates a new `Limiter`.
+   *
+   * @param {Number} [concurrency=Infinity] The maximum number of jobs allowed
+   *     to run concurrently
+   */
+  constructor(concurrency) {
+    this[kDone] = () => {
+      this.pending--;
+      this[kRun]();
+    };
+    this.concurrency = concurrency || Infinity;
+    this.jobs = [];
+    this.pending = 0;
+  }
+
+  /**
+   * Adds a job to the queue.
+   *
+   * @param {Function} job The job to run
+   * @public
+   */
+  add(job) {
+    this.jobs.push(job);
+    this[kRun]();
+  }
+
+  /**
+   * Removes a job from the queue and runs it if possible.
+   *
+   * @private
+   */
+  [kRun]() {
+    if (this.pending === this.concurrency) return;
+
+    if (this.jobs.length) {
+      const job = this.jobs.shift();
+
+      this.pending++;
+      job(this[kDone]);
+    }
+  }
+}
+
+module.exports = Limiter;

devices/panel-preview/node_modules/ws/lib/permessage-deflate.js

@@ -0,0 +1,528 @@
+'use strict';
+
+const zlib = require('zlib');
+
+const bufferUtil = require('./buffer-util');
+const Limiter = require('./limiter');
+const { kStatusCode } = require('./constants');
+
+const FastBuffer = Buffer[Symbol.species];
+const TRAILER = Buffer.from([0x00, 0x00, 0xff, 0xff]);
+const kPerMessageDeflate = Symbol('permessage-deflate');
+const kTotalLength = Symbol('total-length');
+const kCallback = Symbol('callback');
+const kBuffers = Symbol('buffers');
+const kError = Symbol('error');
+
+//
+// We limit zlib concurrency, which prevents severe memory fragmentation
+// as documented in https://github.com/nodejs/node/issues/8871#issuecomment-250915913
+// and https://github.com/websockets/ws/issues/1202
+//
+// Intentionally global; it's the global thread pool that's an issue.
+//
+let zlibLimiter;
+
+/**
+ * permessage-deflate implementation.
+ */
+class PerMessageDeflate {
+  /**
+   * Creates a PerMessageDeflate instance.
+   *
+   * @param {Object} [options] Configuration options
+   * @param {(Boolean|Number)} [options.clientMaxWindowBits] Advertise support
+   *     for, or request, a custom client window size
+   * @param {Boolean} [options.clientNoContextTakeover=false] Advertise/
+   *     acknowledge disabling of client context takeover
+   * @param {Number} [options.concurrencyLimit=10] The number of concurrent
+   *     calls to zlib
+   * @param {(Boolean|Number)} [options.serverMaxWindowBits] Request/confirm the
+   *     use of a custom server window size
+   * @param {Boolean} [options.serverNoContextTakeover=false] Request/accept
+   *     disabling of server context takeover
+   * @param {Number} [options.threshold=1024] Size (in bytes) below which
+   *     messages should not be compressed if context takeover is disabled
+   * @param {Object} [options.zlibDeflateOptions] Options to pass to zlib on
+   *     deflate
+   * @param {Object} [options.zlibInflateOptions] Options to pass to zlib on
+   *     inflate
+   * @param {Boolean} [isServer=false] Create the instance in either server or
+   *     client mode
+   * @param {Number} [maxPayload=0] The maximum allowed message length
+   */
+  constructor(options, isServer, maxPayload) {
+    this._maxPayload = maxPayload | 0;
+    this._options = options || {};
+    this._threshold =
+      this._options.threshold !== undefined ? this._options.threshold : 1024;
+    this._isServer = !!isServer;
+    this._deflate = null;
+    this._inflate = null;
+
+    this.params = null;
+
+    if (!zlibLimiter) {
+      const concurrency =
+        this._options.concurrencyLimit !== undefined
+          ? this._options.concurrencyLimit
+          : 10;
+      zlibLimiter = new Limiter(concurrency);
+    }
+  }
+
+  /**
+   * @type {String}
+   */
+  static get extensionName() {
+    return 'permessage-deflate';
+  }
+
+  /**
+   * Create an extension negotiation offer.
+   *
+   * @return {Object} Extension parameters
+   * @public
+   */
+  offer() {
+    const params = {};
+
+    if (this._options.serverNoContextTakeover) {
+      params.server_no_context_takeover = true;
+    }
+    if (this._options.clientNoContextTakeover) {
+      params.client_no_context_takeover = true;
+    }
+    if (this._options.serverMaxWindowBits) {
+      params.server_max_window_bits = this._options.serverMaxWindowBits;
+    }
+    if (this._options.clientMaxWindowBits) {
+      params.client_max_window_bits = this._options.clientMaxWindowBits;
+    } else if (this._options.clientMaxWindowBits == null) {
+      params.client_max_window_bits = true;
+    }
+
+    return params;
+  }
+
+  /**
+   * Accept an extension negotiation offer/response.
+   *
+   * @param {Array} configurations The extension negotiation offers/reponse
+   * @return {Object} Accepted configuration
+   * @public
+   */
+  accept(configurations) {
+    configurations = this.normalizeParams(configurations);
+
+    this.params = this._isServer
+      ? this.acceptAsServer(configurations)
+      : this.acceptAsClient(configurations);
+
+    return this.params;
+  }
+
+  /**
+   * Releases all resources used by the extension.
+   *
+   * @public
+   */
+  cleanup() {
+    if (this._inflate) {
+      this._inflate.close();
+      this._inflate = null;
+    }
+
+    if (this._deflate) {
+      const callback = this._deflate[kCallback];
+
+      this._deflate.close();
+      this._deflate = null;
+
+      if (callback) {
+        callback(
+          new Error(
+            'The deflate stream was closed while data was being processed'
+          )
+        );
+      }
+    }
+  }
+
+  /**
+   *  Accept an extension negotiation offer.
+   *
+   * @param {Array} offers The extension negotiation offers
+   * @return {Object} Accepted configuration
+   * @private
+   */
+  acceptAsServer(offers) {
+    const opts = this._options;
+    const accepted = offers.find((params) => {
+      if (
+        (opts.serverNoContextTakeover === false &&
+          params.server_no_context_takeover) ||
+        (params.server_max_window_bits &&
+          (opts.serverMaxWindowBits === false ||
+            (typeof opts.serverMaxWindowBits === 'number' &&
+              opts.serverMaxWindowBits > params.server_max_window_bits))) ||
+        (typeof opts.clientMaxWindowBits === 'number' &&
+          !params.client_max_window_bits)
+      ) {
+        return false;
+      }
+
+      return true;
+    });
+
+    if (!accepted) {
+      throw new Error('None of the extension offers can be accepted');
+    }
+
+    if (opts.serverNoContextTakeover) {
+      accepted.server_no_context_takeover = true;
+    }
+    if (opts.clientNoContextTakeover) {
+      accepted.client_no_context_takeover = true;
+    }
+    if (typeof opts.serverMaxWindowBits === 'number') {
+      accepted.server_max_window_bits = opts.serverMaxWindowBits;
+    }
+    if (typeof opts.clientMaxWindowBits === 'number') {
+      accepted.client_max_window_bits = opts.clientMaxWindowBits;
+    } else if (
+      accepted.client_max_window_bits === true ||
+      opts.clientMaxWindowBits === false
+    ) {
+      delete accepted.client_max_window_bits;
+    }
+
+    return accepted;
+  }
+
+  /**
+   * Accept the extension negotiation response.
+   *
+   * @param {Array} response The extension negotiation response
+   * @return {Object} Accepted configuration
+   * @private
+   */
+  acceptAsClient(response) {
+    const params = response[0];
+
+    if (
+      this._options.clientNoContextTakeover === false &&
+      params.client_no_context_takeover
+    ) {
+      throw new Error('Unexpected parameter "client_no_context_takeover"');
+    }
+
+    if (!params.client_max_window_bits) {
+      if (typeof this._options.clientMaxWindowBits === 'number') {
+        params.client_max_window_bits = this._options.clientMaxWindowBits;
+      }
+    } else if (
+      this._options.clientMaxWindowBits === false ||
+      (typeof this._options.clientMaxWindowBits === 'number' &&
+        params.client_max_window_bits > this._options.clientMaxWindowBits)
+    ) {
+      throw new Error(
+        'Unexpected or invalid parameter "client_max_window_bits"'
+      );
+    }
+
+    return params;
+  }
+
+  /**
+   * Normalize parameters.
+   *
+   * @param {Array} configurations The extension negotiation offers/reponse
+   * @return {Array} The offers/response with normalized parameters
+   * @private
+   */
+  normalizeParams(configurations) {
+    configurations.forEach((params) => {
+      Object.keys(params).forEach((key) => {
+        let value = params[key];
+
+        if (value.length > 1) {
+          throw new Error(`Parameter "${key}" must have only a single value`);
+        }
+
+        value = value[0];
+
+        if (key === 'client_max_window_bits') {
+          if (value !== true) {
+            const num = +value;
+            if (!Number.isInteger(num) || num < 8 || num > 15) {
+              throw new TypeError(
+                `Invalid value for parameter "${key}": ${value}`
+              );
+            }
+            value = num;
+          } else if (!this._isServer) {
+            throw new TypeError(
+              `Invalid value for parameter "${key}": ${value}`
+            );
+          }
+        } else if (key === 'server_max_window_bits') {
+          const num = +value;
+          if (!Number.isInteger(num) || num < 8 || num > 15) {
+            throw new TypeError(
+              `Invalid value for parameter "${key}": ${value}`
+            );
+          }
+          value = num;
+        } else if (
+          key === 'client_no_context_takeover' ||
+          key === 'server_no_context_takeover'
+        ) {
+          if (value !== true) {
+            throw new TypeError(
+              `Invalid value for parameter "${key}": ${value}`
+            );
+          }
+        } else {
+          throw new Error(`Unknown parameter "${key}"`);
+        }
+
+        params[key] = value;
+      });
+    });
+
+    return configurations;
+  }
+
+  /**
+   * Decompress data. Concurrency limited.
+   *
+   * @param {Buffer} data Compressed data
+   * @param {Boolean} fin Specifies whether or not this is the last fragment
+   * @param {Function} callback Callback
+   * @public
+   */
+  decompress(data, fin, callback) {
+    zlibLimiter.add((done) => {
+      this._decompress(data, fin, (err, result) => {
+        done();
+        callback(err, result);
+      });
+    });
+  }
+
+  /**
+   * Compress data. Concurrency limited.
+   *
+   * @param {(Buffer|String)} data Data to compress
+   * @param {Boolean} fin Specifies whether or not this is the last fragment
+   * @param {Function} callback Callback
+   * @public
+   */
+  compress(data, fin, callback) {
+    zlibLimiter.add((done) => {
+      this._compress(data, fin, (err, result) => {
+        done();
+        callback(err, result);
+      });
+    });
+  }
+
+  /**
+   * Decompress data.
+   *
+   * @param {Buffer} data Compressed data
+   * @param {Boolean} fin Specifies whether or not this is the last fragment
+   * @param {Function} callback Callback
+   * @private
+   */
+  _decompress(data, fin, callback) {
+    const endpoint = this._isServer ? 'client' : 'server';
+
+    if (!this._inflate) {
+      const key = `${endpoint}_max_window_bits`;
+      const windowBits =
+        typeof this.params[key] !== 'number'
+          ? zlib.Z_DEFAULT_WINDOWBITS
+          : this.params[key];
+
+      this._inflate = zlib.createInflateRaw({
+        ...this._options.zlibInflateOptions,
+        windowBits
+      });
+      this._inflate[kPerMessageDeflate] = this;
+      this._inflate[kTotalLength] = 0;
+      this._inflate[kBuffers] = [];
+      this._inflate.on('error', inflateOnError);
+      this._inflate.on('data', inflateOnData);
+    }
+
+    this._inflate[kCallback] = callback;
+
+    this._inflate.write(data);
+    if (fin) this._inflate.write(TRAILER);
+
+    this._inflate.flush(() => {
+      const err = this._inflate[kError];
+
+      if (err) {
+        this._inflate.close();
+        this._inflate = null;
+        callback(err);
+        return;
+      }
+
+      const data = bufferUtil.concat(
+        this._inflate[kBuffers],
+        this._inflate[kTotalLength]
+      );
+
+      if (this._inflate._readableState.endEmitted) {
+        this._inflate.close();
+        this._inflate = null;
+      } else {
+        this._inflate[kTotalLength] = 0;
+        this._inflate[kBuffers] = [];
+
+        if (fin && this.params[`${endpoint}_no_context_takeover`]) {
+          this._inflate.reset();
+        }
+      }
+
+      callback(null, data);
+    });
+  }
+
+  /**
+   * Compress data.
+   *
+   * @param {(Buffer|String)} data Data to compress
+   * @param {Boolean} fin Specifies whether or not this is the last fragment
+   * @param {Function} callback Callback
+   * @private
+   */
+  _compress(data, fin, callback) {
+    const endpoint = this._isServer ? 'server' : 'client';
+
+    if (!this._deflate) {
+      const key = `${endpoint}_max_window_bits`;
+      const windowBits =
+        typeof this.params[key] !== 'number'
+          ? zlib.Z_DEFAULT_WINDOWBITS
+          : this.params[key];
+
+      this._deflate = zlib.createDeflateRaw({
+        ...this._options.zlibDeflateOptions,
+        windowBits
+      });
+
+      this._deflate[kTotalLength] = 0;
+      this._deflate[kBuffers] = [];
+
+      this._deflate.on('data', deflateOnData);
+    }
+
+    this._deflate[kCallback] = callback;
+
+    this._deflate.write(data);
+    this._deflate.flush(zlib.Z_SYNC_FLUSH, () => {
+      if (!this._deflate) {
+        //
+        // The deflate stream was closed while data was being processed.
+        //
+        return;
+      }
+
+      let data = bufferUtil.concat(
+        this._deflate[kBuffers],
+        this._deflate[kTotalLength]
+      );
+
+      if (fin) {
+        data = new FastBuffer(data.buffer, data.byteOffset, data.length - 4);
+      }
+
+      //
+      // Ensure that the callback will not be called again in
+      // `PerMessageDeflate#cleanup()`.
+      //
+      this._deflate[kCallback] = null;
+
+      this._deflate[kTotalLength] = 0;
+      this._deflate[kBuffers] = [];
+
+      if (fin && this.params[`${endpoint}_no_context_takeover`]) {
+        this._deflate.reset();
+      }
+
+      callback(null, data);
+    });
+  }
+}
+
+module.exports = PerMessageDeflate;
+
+/**
+ * The listener of the `zlib.DeflateRaw` stream `'data'` event.
+ *
+ * @param {Buffer} chunk A chunk of data
+ * @private
+ */
+function deflateOnData(chunk) {
+  this[kBuffers].push(chunk);
+  this[kTotalLength] += chunk.length;
+}
+
+/**
+ * The listener of the `zlib.InflateRaw` stream `'data'` event.
+ *
+ * @param {Buffer} chunk A chunk of data
+ * @private
+ */
+function inflateOnData(chunk) {
+  this[kTotalLength] += chunk.length;
+
+  if (
+    this[kPerMessageDeflate]._maxPayload < 1 ||
+    this[kTotalLength] <= this[kPerMessageDeflate]._maxPayload
+  ) {
+    this[kBuffers].push(chunk);
+    return;
+  }
+
+  this[kError] = new RangeError('Max payload size exceeded');
+  this[kError].code = 'WS_ERR_UNSUPPORTED_MESSAGE_LENGTH';
+  this[kError][kStatusCode] = 1009;
+  this.removeListener('data', inflateOnData);
+
+  //
+  // The choice to employ `zlib.reset()` over `zlib.close()` is dictated by the
+  // fact that in Node.js versions prior to 13.10.0, the callback for
+  // `zlib.flush()` is not called if `zlib.close()` is used. Utilizing
+  // `zlib.reset()` ensures that either the callback is invoked or an error is
+  // emitted.
+  //
+  this.reset();
+}
+
+/**
+ * The listener of the `zlib.InflateRaw` stream `'error'` event.
+ *
+ * @param {Error} err The emitted error
+ * @private
+ */
+function inflateOnError(err) {
+  //
+  // There is no need to call `Zlib#close()` as the handle is automatically
+  // closed when an error is emitted.
+  //
+  this[kPerMessageDeflate]._inflate = null;
+
+  if (this[kError]) {
+    this[kCallback](this[kError]);
+    return;
+  }
+
+  err[kStatusCode] = 1007;
+  this[kCallback](err);
+}

devices/panel-preview/node_modules/ws/lib/receiver.js

@@ -0,0 +1,706 @@
+'use strict';
+
+const { Writable } = require('stream');
+
+const PerMessageDeflate = require('./permessage-deflate');
+const {
+  BINARY_TYPES,
+  EMPTY_BUFFER,
+  kStatusCode,
+  kWebSocket
+} = require('./constants');
+const { concat, toArrayBuffer, unmask } = require('./buffer-util');
+const { isValidStatusCode, isValidUTF8 } = require('./validation');
+
+const FastBuffer = Buffer[Symbol.species];
+
+const GET_INFO = 0;
+const GET_PAYLOAD_LENGTH_16 = 1;
+const GET_PAYLOAD_LENGTH_64 = 2;
+const GET_MASK = 3;
+const GET_DATA = 4;
+const INFLATING = 5;
+const DEFER_EVENT = 6;
+
+/**
+ * HyBi Receiver implementation.
+ *
+ * @extends Writable
+ */
+class Receiver extends Writable {
+  /**
+   * Creates a Receiver instance.
+   *
+   * @param {Object} [options] Options object
+   * @param {Boolean} [options.allowSynchronousEvents=true] Specifies whether
+   *     any of the `'message'`, `'ping'`, and `'pong'` events can be emitted
+   *     multiple times in the same tick
+   * @param {String} [options.binaryType=nodebuffer] The type for binary data
+   * @param {Object} [options.extensions] An object containing the negotiated
+   *     extensions
+   * @param {Boolean} [options.isServer=false] Specifies whether to operate in
+   *     client or server mode
+   * @param {Number} [options.maxPayload=0] The maximum allowed message length
+   * @param {Boolean} [options.skipUTF8Validation=false] Specifies whether or
+   *     not to skip UTF-8 validation for text and close messages
+   */
+  constructor(options = {}) {
+    super();
+
+    this._allowSynchronousEvents =
+      options.allowSynchronousEvents !== undefined
+        ? options.allowSynchronousEvents
+        : true;
+    this._binaryType = options.binaryType || BINARY_TYPES[0];
+    this._extensions = options.extensions || {};
+    this._isServer = !!options.isServer;
+    this._maxPayload = options.maxPayload | 0;
+    this._skipUTF8Validation = !!options.skipUTF8Validation;
+    this[kWebSocket] = undefined;
+
+    this._bufferedBytes = 0;
+    this._buffers = [];
+
+    this._compressed = false;
+    this._payloadLength = 0;
+    this._mask = undefined;
+    this._fragmented = 0;
+    this._masked = false;
+    this._fin = false;
+    this._opcode = 0;
+
+    this._totalPayloadLength = 0;
+    this._messageLength = 0;
+    this._fragments = [];
+
+    this._errored = false;
+    this._loop = false;
+    this._state = GET_INFO;
+  }
+
+  /**
+   * Implements `Writable.prototype._write()`.
+   *
+   * @param {Buffer} chunk The chunk of data to write
+   * @param {String} encoding The character encoding of `chunk`
+   * @param {Function} cb Callback
+   * @private
+   */
+  _write(chunk, encoding, cb) {
+    if (this._opcode === 0x08 && this._state == GET_INFO) return cb();
+
+    this._bufferedBytes += chunk.length;
+    this._buffers.push(chunk);
+    this.startLoop(cb);
+  }
+
+  /**
+   * Consumes `n` bytes from the buffered data.
+   *
+   * @param {Number} n The number of bytes to consume
+   * @return {Buffer} The consumed bytes
+   * @private
+   */
+  consume(n) {
+    this._bufferedBytes -= n;
+
+    if (n === this._buffers[0].length) return this._buffers.shift();
+
+    if (n < this._buffers[0].length) {
+      const buf = this._buffers[0];
+      this._buffers[0] = new FastBuffer(
+        buf.buffer,
+        buf.byteOffset + n,
+        buf.length - n
+      );
+
+      return new FastBuffer(buf.buffer, buf.byteOffset, n);
+    }
+
+    const dst = Buffer.allocUnsafe(n);
+
+    do {
+      const buf = this._buffers[0];
+      const offset = dst.length - n;
+
+      if (n >= buf.length) {
+        dst.set(this._buffers.shift(), offset);
+      } else {
+        dst.set(new Uint8Array(buf.buffer, buf.byteOffset, n), offset);
+        this._buffers[0] = new FastBuffer(
+          buf.buffer,
+          buf.byteOffset + n,
+          buf.length - n
+        );
+      }
+
+      n -= buf.length;
+    } while (n > 0);
+
+    return dst;
+  }
+
+  /**
+   * Starts the parsing loop.
+   *
+   * @param {Function} cb Callback
+   * @private
+   */
+  startLoop(cb) {
+    this._loop = true;
+
+    do {
+      switch (this._state) {
+        case GET_INFO:
+          this.getInfo(cb);
+          break;
+        case GET_PAYLOAD_LENGTH_16:
+          this.getPayloadLength16(cb);
+          break;
+        case GET_PAYLOAD_LENGTH_64:
+          this.getPayloadLength64(cb);
+          break;
+        case GET_MASK:
+          this.getMask();
+          break;
+        case GET_DATA:
+          this.getData(cb);
+          break;
+        case INFLATING:
+        case DEFER_EVENT:
+          this._loop = false;
+          return;
+      }
+    } while (this._loop);
+
+    if (!this._errored) cb();
+  }
+
+  /**
+   * Reads the first two bytes of a frame.
+   *
+   * @param {Function} cb Callback
+   * @private
+   */
+  getInfo(cb) {
+    if (this._bufferedBytes < 2) {
+      this._loop = false;
+      return;
+    }
+
+    const buf = this.consume(2);
+
+    if ((buf[0] & 0x30) !== 0x00) {
+      const error = this.createError(
+        RangeError,
+        'RSV2 and RSV3 must be clear',
+        true,
+        1002,
+        'WS_ERR_UNEXPECTED_RSV_2_3'
+      );
+
+      cb(error);
+      return;
+    }
+
+    const compressed = (buf[0] & 0x40) === 0x40;
+
+    if (compressed && !this._extensions[PerMessageDeflate.extensionName]) {
+      const error = this.createError(
+        RangeError,
+        'RSV1 must be clear',
+        true,
+        1002,
+        'WS_ERR_UNEXPECTED_RSV_1'
+      );
+
+      cb(error);
+      return;
+    }
+
+    this._fin = (buf[0] & 0x80) === 0x80;
+    this._opcode = buf[0] & 0x0f;
+    this._payloadLength = buf[1] & 0x7f;
+
+    if (this._opcode === 0x00) {
+      if (compressed) {
+        const error = this.createError(
+          RangeError,
+          'RSV1 must be clear',
+          true,
+          1002,
+          'WS_ERR_UNEXPECTED_RSV_1'
+        );
+
+        cb(error);
+        return;
+      }
+
+      if (!this._fragmented) {
+        const error = this.createError(
+          RangeError,
+          'invalid opcode 0',
+          true,
+          1002,
+          'WS_ERR_INVALID_OPCODE'
+        );
+
+        cb(error);
+        return;
+      }
+
+      this._opcode = this._fragmented;
+    } else if (this._opcode === 0x01 || this._opcode === 0x02) {
+      if (this._fragmented) {
+        const error = this.createError(
+          RangeError,
+          `invalid opcode ${this._opcode}`,
+          true,
+          1002,
+          'WS_ERR_INVALID_OPCODE'
+        );
+
+        cb(error);
+        return;
+      }
+
+      this._compressed = compressed;
+    } else if (this._opcode > 0x07 && this._opcode < 0x0b) {
+      if (!this._fin) {
+        const error = this.createError(
+          RangeError,
+          'FIN must be set',
+          true,
+          1002,
+          'WS_ERR_EXPECTED_FIN'
+        );
+
+        cb(error);
+        return;
+      }
+
+      if (compressed) {
+        const error = this.createError(
+          RangeError,
+          'RSV1 must be clear',
+          true,
+          1002,
+          'WS_ERR_UNEXPECTED_RSV_1'
+        );
+
+        cb(error);
+        return;
+      }
+
+      if (
+        this._payloadLength > 0x7d ||
+        (this._opcode === 0x08 && this._payloadLength === 1)
+      ) {
+        const error = this.createError(
+          RangeError,
+          `invalid payload length ${this._payloadLength}`,
+          true,
+          1002,
+          'WS_ERR_INVALID_CONTROL_PAYLOAD_LENGTH'
+        );
+
+        cb(error);
+        return;
+      }
+    } else {
+      const error = this.createError(
+        RangeError,
+        `invalid opcode ${this._opcode}`,
+        true,
+        1002,
+        'WS_ERR_INVALID_OPCODE'
+      );
+
+      cb(error);
+      return;
+    }
+
+    if (!this._fin && !this._fragmented) this._fragmented = this._opcode;
+    this._masked = (buf[1] & 0x80) === 0x80;
+
+    if (this._isServer) {
+      if (!this._masked) {
+        const error = this.createError(
+          RangeError,
+          'MASK must be set',
+          true,
+          1002,
+          'WS_ERR_EXPECTED_MASK'
+        );
+
+        cb(error);
+        return;
+      }
+    } else if (this._masked) {
+      const error = this.createError(
+        RangeError,
+        'MASK must be clear',
+        true,
+        1002,
+        'WS_ERR_UNEXPECTED_MASK'
+      );
+
+      cb(error);
+      return;
+    }
+
+    if (this._payloadLength === 126) this._state = GET_PAYLOAD_LENGTH_16;
+    else if (this._payloadLength === 127) this._state = GET_PAYLOAD_LENGTH_64;
+    else this.haveLength(cb);
+  }
+
+  /**
+   * Gets extended payload length (7+16).
+   *
+   * @param {Function} cb Callback
+   * @private
+   */
+  getPayloadLength16(cb) {
+    if (this._bufferedBytes < 2) {
+      this._loop = false;
+      return;
+    }
+
+    this._payloadLength = this.consume(2).readUInt16BE(0);
+    this.haveLength(cb);
+  }
+
+  /**
+   * Gets extended payload length (7+64).
+   *
+   * @param {Function} cb Callback
+   * @private
+   */
+  getPayloadLength64(cb) {
+    if (this._bufferedBytes < 8) {
+      this._loop = false;
+      return;
+    }
+
+    const buf = this.consume(8);
+    const num = buf.readUInt32BE(0);
+
+    //
+    // The maximum safe integer in JavaScript is 2^53 - 1. An error is returned
+    // if payload length is greater than this number.
+    //
+    if (num > Math.pow(2, 53 - 32) - 1) {
+      const error = this.createError(
+        RangeError,
+        'Unsupported WebSocket frame: payload length > 2^53 - 1',
+        false,
+        1009,
+        'WS_ERR_UNSUPPORTED_DATA_PAYLOAD_LENGTH'
+      );
+
+      cb(error);
+      return;
+    }
+
+    this._payloadLength = num * Math.pow(2, 32) + buf.readUInt32BE(4);
+    this.haveLength(cb);
+  }
+
+  /**
+   * Payload length has been read.
+   *
+   * @param {Function} cb Callback
+   * @private
+   */
+  haveLength(cb) {
+    if (this._payloadLength && this._opcode < 0x08) {
+      this._totalPayloadLength += this._payloadLength;
+      if (this._totalPayloadLength > this._maxPayload && this._maxPayload > 0) {
+        const error = this.createError(
+          RangeError,
+          'Max payload size exceeded',
+          false,
+          1009,
+          'WS_ERR_UNSUPPORTED_MESSAGE_LENGTH'
+        );
+
+        cb(error);
+        return;
+      }
+    }
+
+    if (this._masked) this._state = GET_MASK;
+    else this._state = GET_DATA;
+  }
+
+  /**
+   * Reads mask bytes.
+   *
+   * @private
+   */
+  getMask() {
+    if (this._bufferedBytes < 4) {
+      this._loop = false;
+      return;
+    }
+
+    this._mask = this.consume(4);
+    this._state = GET_DATA;
+  }
+
+  /**
+   * Reads data bytes.
+   *
+   * @param {Function} cb Callback
+   * @private
+   */
+  getData(cb) {
+    let data = EMPTY_BUFFER;
+
+    if (this._payloadLength) {
+      if (this._bufferedBytes < this._payloadLength) {
+        this._loop = false;
+        return;
+      }
+
+      data = this.consume(this._payloadLength);
+
+      if (
+        this._masked &&
+        (this._mask[0] | this._mask[1] | this._mask[2] | this._mask[3]) !== 0
+      ) {
+        unmask(data, this._mask);
+      }
+    }
+
+    if (this._opcode > 0x07) {
+      this.controlMessage(data, cb);
+      return;
+    }
+
+    if (this._compressed) {
+      this._state = INFLATING;
+      this.decompress(data, cb);
+      return;
+    }
+
+    if (data.length) {
+      //
+      // This message is not compressed so its length is the sum of the payload
+      // length of all fragments.
+      //
+      this._messageLength = this._totalPayloadLength;
+      this._fragments.push(data);
+    }
+
+    this.dataMessage(cb);
+  }
+
+  /**
+   * Decompresses data.
+   *
+   * @param {Buffer} data Compressed data
+   * @param {Function} cb Callback
+   * @private
+   */
+  decompress(data, cb) {
+    const perMessageDeflate = this._extensions[PerMessageDeflate.extensionName];
+
+    perMessageDeflate.decompress(data, this._fin, (err, buf) => {
+      if (err) return cb(err);
+
+      if (buf.length) {
+        this._messageLength += buf.length;
+        if (this._messageLength > this._maxPayload && this._maxPayload > 0) {
+          const error = this.createError(
+            RangeError,
+            'Max payload size exceeded',
+            false,
+            1009,
+            'WS_ERR_UNSUPPORTED_MESSAGE_LENGTH'
+          );
+
+          cb(error);
+          return;
+        }
+
+        this._fragments.push(buf);
+      }
+
+      this.dataMessage(cb);
+      if (this._state === GET_INFO) this.startLoop(cb);
+    });
+  }
+
+  /**
+   * Handles a data message.
+   *
+   * @param {Function} cb Callback
+   * @private
+   */
+  dataMessage(cb) {
+    if (!this._fin) {
+      this._state = GET_INFO;
+      return;
+    }
+
+    const messageLength = this._messageLength;
+    const fragments = this._fragments;
+
+    this._totalPayloadLength = 0;
+    this._messageLength = 0;
+    this._fragmented = 0;
+    this._fragments = [];
+
+    if (this._opcode === 2) {
+      let data;
+
+      if (this._binaryType === 'nodebuffer') {
+        data = concat(fragments, messageLength);
+      } else if (this._binaryType === 'arraybuffer') {
+        data = toArrayBuffer(concat(fragments, messageLength));
+      } else if (this._binaryType === 'blob') {
+        data = new Blob(fragments);
+      } else {
+        data = fragments;
+      }
+
+      if (this._allowSynchronousEvents) {
+        this.emit('message', data, true);
+        this._state = GET_INFO;
+      } else {
+        this._state = DEFER_EVENT;
+        setImmediate(() => {
+          this.emit('message', data, true);
+          this._state = GET_INFO;
+          this.startLoop(cb);
+        });
+      }
+    } else {
+      const buf = concat(fragments, messageLength);
+
+      if (!this._skipUTF8Validation && !isValidUTF8(buf)) {
+        const error = this.createError(
+          Error,
+          'invalid UTF-8 sequence',
+          true,
+          1007,
+          'WS_ERR_INVALID_UTF8'
+        );
+
+        cb(error);
+        return;
+      }
+
+      if (this._state === INFLATING || this._allowSynchronousEvents) {
+        this.emit('message', buf, false);
+        this._state = GET_INFO;
+      } else {
+        this._state = DEFER_EVENT;
+        setImmediate(() => {
+          this.emit('message', buf, false);
+          this._state = GET_INFO;
+          this.startLoop(cb);
+        });
+      }
+    }
+  }
+
+  /**
+   * Handles a control message.
+   *
+   * @param {Buffer} data Data to handle
+   * @return {(Error|RangeError|undefined)} A possible error
+   * @private
+   */
+  controlMessage(data, cb) {
+    if (this._opcode === 0x08) {
+      if (data.length === 0) {
+        this._loop = false;
+        this.emit('conclude', 1005, EMPTY_BUFFER);
+        this.end();
+      } else {
+        const code = data.readUInt16BE(0);
+
+        if (!isValidStatusCode(code)) {
+          const error = this.createError(
+            RangeError,
+            `invalid status code ${code}`,
+            true,
+            1002,
+            'WS_ERR_INVALID_CLOSE_CODE'
+          );
+
+          cb(error);
+          return;
+        }
+
+        const buf = new FastBuffer(
+          data.buffer,
+          data.byteOffset + 2,
+          data.length - 2
+        );
+
+        if (!this._skipUTF8Validation && !isValidUTF8(buf)) {
+          const error = this.createError(
+            Error,
+            'invalid UTF-8 sequence',
+            true,
+            1007,
+            'WS_ERR_INVALID_UTF8'
+          );
+
+          cb(error);
+          return;
+        }
+
+        this._loop = false;
+        this.emit('conclude', code, buf);
+        this.end();
+      }
+
+      this._state = GET_INFO;
+      return;
+    }
+
+    if (this._allowSynchronousEvents) {
+      this.emit(this._opcode === 0x09 ? 'ping' : 'pong', data);
+      this._state = GET_INFO;
+    } else {
+      this._state = DEFER_EVENT;
+      setImmediate(() => {
+        this.emit(this._opcode === 0x09 ? 'ping' : 'pong', data);
+        this._state = GET_INFO;
+        this.startLoop(cb);
+      });
+    }
+  }
+
+  /**
+   * Builds an error object.
+   *
+   * @param {function(new:Error|RangeError)} ErrorCtor The error constructor
+   * @param {String} message The error message
+   * @param {Boolean} prefix Specifies whether or not to add a default prefix to
+   *     `message`
+   * @param {Number} statusCode The status code
+   * @param {String} errorCode The exposed error code
+   * @return {(Error|RangeError)} The error
+   * @private
+   */
+  createError(ErrorCtor, message, prefix, statusCode, errorCode) {
+    this._loop = false;
+    this._errored = true;
+
+    const err = new ErrorCtor(
+      prefix ? `Invalid WebSocket frame: ${message}` : message
+    );
+
+    Error.captureStackTrace(err, this.createError);
+    err.code = errorCode;
+    err[kStatusCode] = statusCode;
+    return err;
+  }
+}
+
+module.exports = Receiver;

devices/panel-preview/node_modules/ws/lib/sender.js

@@ -0,0 +1,602 @@
+/* eslint no-unused-vars: ["error", { "varsIgnorePattern": "^Duplex" }] */
+
+'use strict';
+
+const { Duplex } = require('stream');
+const { randomFillSync } = require('crypto');
+
+const PerMessageDeflate = require('./permessage-deflate');
+const { EMPTY_BUFFER, kWebSocket, NOOP } = require('./constants');
+const { isBlob, isValidStatusCode } = require('./validation');
+const { mask: applyMask, toBuffer } = require('./buffer-util');
+
+const kByteLength = Symbol('kByteLength');
+const maskBuffer = Buffer.alloc(4);
+const RANDOM_POOL_SIZE = 8 * 1024;
+let randomPool;
+let randomPoolPointer = RANDOM_POOL_SIZE;
+
+const DEFAULT = 0;
+const DEFLATING = 1;
+const GET_BLOB_DATA = 2;
+
+/**
+ * HyBi Sender implementation.
+ */
+class Sender {
+  /**
+   * Creates a Sender instance.
+   *
+   * @param {Duplex} socket The connection socket
+   * @param {Object} [extensions] An object containing the negotiated extensions
+   * @param {Function} [generateMask] The function used to generate the masking
+   *     key
+   */
+  constructor(socket, extensions, generateMask) {
+    this._extensions = extensions || {};
+
+    if (generateMask) {
+      this._generateMask = generateMask;
+      this._maskBuffer = Buffer.alloc(4);
+    }
+
+    this._socket = socket;
+
+    this._firstFragment = true;
+    this._compress = false;
+
+    this._bufferedBytes = 0;
+    this._queue = [];
+    this._state = DEFAULT;
+    this.onerror = NOOP;
+    this[kWebSocket] = undefined;
+  }
+
+  /**
+   * Frames a piece of data according to the HyBi WebSocket protocol.
+   *
+   * @param {(Buffer|String)} data The data to frame
+   * @param {Object} options Options object
+   * @param {Boolean} [options.fin=false] Specifies whether or not to set the
+   *     FIN bit
+   * @param {Function} [options.generateMask] The function used to generate the
+   *     masking key
+   * @param {Boolean} [options.mask=false] Specifies whether or not to mask
+   *     `data`
+   * @param {Buffer} [options.maskBuffer] The buffer used to store the masking
+   *     key
+   * @param {Number} options.opcode The opcode
+   * @param {Boolean} [options.readOnly=false] Specifies whether `data` can be
+   *     modified
+   * @param {Boolean} [options.rsv1=false] Specifies whether or not to set the
+   *     RSV1 bit
+   * @return {(Buffer|String)[]} The framed data
+   * @public
+   */
+  static frame(data, options) {
+    let mask;
+    let merge = false;
+    let offset = 2;
+    let skipMasking = false;
+
+    if (options.mask) {
+      mask = options.maskBuffer || maskBuffer;
+
+      if (options.generateMask) {
+        options.generateMask(mask);
+      } else {
+        if (randomPoolPointer === RANDOM_POOL_SIZE) {
+          /* istanbul ignore else  */
+          if (randomPool === undefined) {
+            //
+            // This is lazily initialized because server-sent frames must not
+            // be masked so it may never be used.
+            //
+            randomPool = Buffer.alloc(RANDOM_POOL_SIZE);
+          }
+
+          randomFillSync(randomPool, 0, RANDOM_POOL_SIZE);
+          randomPoolPointer = 0;
+        }
+
+        mask[0] = randomPool[randomPoolPointer++];
+        mask[1] = randomPool[randomPoolPointer++];
+        mask[2] = randomPool[randomPoolPointer++];
+        mask[3] = randomPool[randomPoolPointer++];
+      }
+
+      skipMasking = (mask[0] | mask[1] | mask[2] | mask[3]) === 0;
+      offset = 6;
+    }
+
+    let dataLength;
+
+    if (typeof data === 'string') {
+      if (
+        (!options.mask || skipMasking) &&
+        options[kByteLength] !== undefined
+      ) {
+        dataLength = options[kByteLength];
+      } else {
+        data = Buffer.from(data);
+        dataLength = data.length;
+      }
+    } else {
+      dataLength = data.length;
+      merge = options.mask && options.readOnly && !skipMasking;
+    }
+
+    let payloadLength = dataLength;
+
+    if (dataLength >= 65536) {
+      offset += 8;
+      payloadLength = 127;
+    } else if (dataLength > 125) {
+      offset += 2;
+      payloadLength = 126;
+    }
+
+    const target = Buffer.allocUnsafe(merge ? dataLength + offset : offset);
+
+    target[0] = options.fin ? options.opcode | 0x80 : options.opcode;
+    if (options.rsv1) target[0] |= 0x40;
+
+    target[1] = payloadLength;
+
+    if (payloadLength === 126) {
+      target.writeUInt16BE(dataLength, 2);
+    } else if (payloadLength === 127) {
+      target[2] = target[3] = 0;
+      target.writeUIntBE(dataLength, 4, 6);
+    }
+
+    if (!options.mask) return [target, data];
+
+    target[1] |= 0x80;
+    target[offset - 4] = mask[0];
+    target[offset - 3] = mask[1];
+    target[offset - 2] = mask[2];
+    target[offset - 1] = mask[3];
+
+    if (skipMasking) return [target, data];
+
+    if (merge) {
+      applyMask(data, mask, target, offset, dataLength);
+      return [target];
+    }
+
+    applyMask(data, mask, data, 0, dataLength);
+    return [target, data];
+  }
+
+  /**
+   * Sends a close message to the other peer.
+   *
+   * @param {Number} [code] The status code component of the body
+   * @param {(String|Buffer)} [data] The message component of the body
+   * @param {Boolean} [mask=false] Specifies whether or not to mask the message
+   * @param {Function} [cb] Callback
+   * @public
+   */
+  close(code, data, mask, cb) {
+    let buf;
+
+    if (code === undefined) {
+      buf = EMPTY_BUFFER;
+    } else if (typeof code !== 'number' || !isValidStatusCode(code)) {
+      throw new TypeError('First argument must be a valid error code number');
+    } else if (data === undefined || !data.length) {
+      buf = Buffer.allocUnsafe(2);
+      buf.writeUInt16BE(code, 0);
+    } else {
+      const length = Buffer.byteLength(data);
+
+      if (length > 123) {
+        throw new RangeError('The message must not be greater than 123 bytes');
+      }
+
+      buf = Buffer.allocUnsafe(2 + length);
+      buf.writeUInt16BE(code, 0);
+
+      if (typeof data === 'string') {
+        buf.write(data, 2);
+      } else {
+        buf.set(data, 2);
+      }
+    }
+
+    const options = {
+      [kByteLength]: buf.length,
+      fin: true,
+      generateMask: this._generateMask,
+      mask,
+      maskBuffer: this._maskBuffer,
+      opcode: 0x08,
+      readOnly: false,
+      rsv1: false
+    };
+
+    if (this._state !== DEFAULT) {
+      this.enqueue([this.dispatch, buf, false, options, cb]);
+    } else {
+      this.sendFrame(Sender.frame(buf, options), cb);
+    }
+  }
+
+  /**
+   * Sends a ping message to the other peer.
+   *
+   * @param {*} data The message to send
+   * @param {Boolean} [mask=false] Specifies whether or not to mask `data`
+   * @param {Function} [cb] Callback
+   * @public
+   */
+  ping(data, mask, cb) {
+    let byteLength;
+    let readOnly;
+
+    if (typeof data === 'string') {
+      byteLength = Buffer.byteLength(data);
+      readOnly = false;
+    } else if (isBlob(data)) {
+      byteLength = data.size;
+      readOnly = false;
+    } else {
+      data = toBuffer(data);
+      byteLength = data.length;
+      readOnly = toBuffer.readOnly;
+    }
+
+    if (byteLength > 125) {
+      throw new RangeError('The data size must not be greater than 125 bytes');
+    }
+
+    const options = {
+      [kByteLength]: byteLength,
+      fin: true,
+      generateMask: this._generateMask,
+      mask,
+      maskBuffer: this._maskBuffer,
+      opcode: 0x09,
+      readOnly,
+      rsv1: false
+    };
+
+    if (isBlob(data)) {
+      if (this._state !== DEFAULT) {
+        this.enqueue([this.getBlobData, data, false, options, cb]);
+      } else {
+        this.getBlobData(data, false, options, cb);
+      }
+    } else if (this._state !== DEFAULT) {
+      this.enqueue([this.dispatch, data, false, options, cb]);
+    } else {
+      this.sendFrame(Sender.frame(data, options), cb);
+    }
+  }
+
+  /**
+   * Sends a pong message to the other peer.
+   *
+   * @param {*} data The message to send
+   * @param {Boolean} [mask=false] Specifies whether or not to mask `data`
+   * @param {Function} [cb] Callback
+   * @public
+   */
+  pong(data, mask, cb) {
+    let byteLength;
+    let readOnly;
+
+    if (typeof data === 'string') {
+      byteLength = Buffer.byteLength(data);
+      readOnly = false;
+    } else if (isBlob(data)) {
+      byteLength = data.size;
+      readOnly = false;
+    } else {
+      data = toBuffer(data);
+      byteLength = data.length;
+      readOnly = toBuffer.readOnly;
+    }
+
+    if (byteLength > 125) {
+      throw new RangeError('The data size must not be greater than 125 bytes');
+    }
+
+    const options = {
+      [kByteLength]: byteLength,
+      fin: true,
+      generateMask: this._generateMask,
+      mask,
+      maskBuffer: this._maskBuffer,
+      opcode: 0x0a,
+      readOnly,
+      rsv1: false
+    };
+
+    if (isBlob(data)) {
+      if (this._state !== DEFAULT) {
+        this.enqueue([this.getBlobData, data, false, options, cb]);
+      } else {
+        this.getBlobData(data, false, options, cb);
+      }
+    } else if (this._state !== DEFAULT) {
+      this.enqueue([this.dispatch, data, false, options, cb]);
+    } else {
+      this.sendFrame(Sender.frame(data, options), cb);
+    }
+  }
+
+  /**
+   * Sends a data message to the other peer.
+   *
+   * @param {*} data The message to send
+   * @param {Object} options Options object
+   * @param {Boolean} [options.binary=false] Specifies whether `data` is binary
+   *     or text
+   * @param {Boolean} [options.compress=false] Specifies whether or not to
+   *     compress `data`
+   * @param {Boolean} [options.fin=false] Specifies whether the fragment is the
+   *     last one
+   * @param {Boolean} [options.mask=false] Specifies whether or not to mask
+   *     `data`
+   * @param {Function} [cb] Callback
+   * @public
+   */
+  send(data, options, cb) {
+    const perMessageDeflate = this._extensions[PerMessageDeflate.extensionName];
+    let opcode = options.binary ? 2 : 1;
+    let rsv1 = options.compress;
+
+    let byteLength;
+    let readOnly;
+
+    if (typeof data === 'string') {
+      byteLength = Buffer.byteLength(data);
+      readOnly = false;
+    } else if (isBlob(data)) {
+      byteLength = data.size;
+      readOnly = false;
+    } else {
+      data = toBuffer(data);
+      byteLength = data.length;
+      readOnly = toBuffer.readOnly;
+    }
+
+    if (this._firstFragment) {
+      this._firstFragment = false;
+      if (
+        rsv1 &&
+        perMessageDeflate &&
+        perMessageDeflate.params[
+          perMessageDeflate._isServer
+            ? 'server_no_context_takeover'
+            : 'client_no_context_takeover'
+        ]
+      ) {
+        rsv1 = byteLength >= perMessageDeflate._threshold;
+      }
+      this._compress = rsv1;
+    } else {
+      rsv1 = false;
+      opcode = 0;
+    }
+
+    if (options.fin) this._firstFragment = true;
+
+    const opts = {
+      [kByteLength]: byteLength,
+      fin: options.fin,
+      generateMask: this._generateMask,
+      mask: options.mask,
+      maskBuffer: this._maskBuffer,
+      opcode,
+      readOnly,
+      rsv1
+    };
+
+    if (isBlob(data)) {
+      if (this._state !== DEFAULT) {
+        this.enqueue([this.getBlobData, data, this._compress, opts, cb]);
+      } else {
+        this.getBlobData(data, this._compress, opts, cb);
+      }
+    } else if (this._state !== DEFAULT) {
+      this.enqueue([this.dispatch, data, this._compress, opts, cb]);
+    } else {
+      this.dispatch(data, this._compress, opts, cb);
+    }
+  }
+
+  /**
+   * Gets the contents of a blob as binary data.
+   *
+   * @param {Blob} blob The blob
+   * @param {Boolean} [compress=false] Specifies whether or not to compress
+   *     the data
+   * @param {Object} options Options object
+   * @param {Boolean} [options.fin=false] Specifies whether or not to set the
+   *     FIN bit
+   * @param {Function} [options.generateMask] The function used to generate the
+   *     masking key
+   * @param {Boolean} [options.mask=false] Specifies whether or not to mask
+   *     `data`
+   * @param {Buffer} [options.maskBuffer] The buffer used to store the masking
+   *     key
+   * @param {Number} options.opcode The opcode
+   * @param {Boolean} [options.readOnly=false] Specifies whether `data` can be
+   *     modified
+   * @param {Boolean} [options.rsv1=false] Specifies whether or not to set the
+   *     RSV1 bit
+   * @param {Function} [cb] Callback
+   * @private
+   */
+  getBlobData(blob, compress, options, cb) {
+    this._bufferedBytes += options[kByteLength];
+    this._state = GET_BLOB_DATA;
+
+    blob
+      .arrayBuffer()
+      .then((arrayBuffer) => {
+        if (this._socket.destroyed) {
+          const err = new Error(
+            'The socket was closed while the blob was being read'
+          );
+
+          //
+          // `callCallbacks` is called in the next tick to ensure that errors
+          // that might be thrown in the callbacks behave like errors thrown
+          // outside the promise chain.
+          //
+          process.nextTick(callCallbacks, this, err, cb);
+          return;
+        }
+
+        this._bufferedBytes -= options[kByteLength];
+        const data = toBuffer(arrayBuffer);
+
+        if (!compress) {
+          this._state = DEFAULT;
+          this.sendFrame(Sender.frame(data, options), cb);
+          this.dequeue();
+        } else {
+          this.dispatch(data, compress, options, cb);
+        }
+      })
+      .catch((err) => {
+        //
+        // `onError` is called in the next tick for the same reason that
+        // `callCallbacks` above is.
+        //
+        process.nextTick(onError, this, err, cb);
+      });
+  }
+
+  /**
+   * Dispatches a message.
+   *
+   * @param {(Buffer|String)} data The message to send
+   * @param {Boolean} [compress=false] Specifies whether or not to compress
+   *     `data`
+   * @param {Object} options Options object
+   * @param {Boolean} [options.fin=false] Specifies whether or not to set the
+   *     FIN bit
+   * @param {Function} [options.generateMask] The function used to generate the
+   *     masking key
+   * @param {Boolean} [options.mask=false] Specifies whether or not to mask
+   *     `data`
+   * @param {Buffer} [options.maskBuffer] The buffer used to store the masking
+   *     key
+   * @param {Number} options.opcode The opcode
+   * @param {Boolean} [options.readOnly=false] Specifies whether `data` can be
+   *     modified
+   * @param {Boolean} [options.rsv1=false] Specifies whether or not to set the
+   *     RSV1 bit
+   * @param {Function} [cb] Callback
+   * @private
+   */
+  dispatch(data, compress, options, cb) {
+    if (!compress) {
+      this.sendFrame(Sender.frame(data, options), cb);
+      return;
+    }
+
+    const perMessageDeflate = this._extensions[PerMessageDeflate.extensionName];
+
+    this._bufferedBytes += options[kByteLength];
+    this._state = DEFLATING;
+    perMessageDeflate.compress(data, options.fin, (_, buf) => {
+      if (this._socket.destroyed) {
+        const err = new Error(
+          'The socket was closed while data was being compressed'
+        );
+
+        callCallbacks(this, err, cb);
+        return;
+      }
+
+      this._bufferedBytes -= options[kByteLength];
+      this._state = DEFAULT;
+      options.readOnly = false;
+      this.sendFrame(Sender.frame(buf, options), cb);
+      this.dequeue();
+    });
+  }
+
+  /**
+   * Executes queued send operations.
+   *
+   * @private
+   */
+  dequeue() {
+    while (this._state === DEFAULT && this._queue.length) {
+      const params = this._queue.shift();
+
+      this._bufferedBytes -= params[3][kByteLength];
+      Reflect.apply(params[0], this, params.slice(1));
+    }
+  }
+
+  /**
+   * Enqueues a send operation.
+   *
+   * @param {Array} params Send operation parameters.
+   * @private
+   */
+  enqueue(params) {
+    this._bufferedBytes += params[3][kByteLength];
+    this._queue.push(params);
+  }
+
+  /**
+   * Sends a frame.
+   *
+   * @param {(Buffer | String)[]} list The frame to send
+   * @param {Function} [cb] Callback
+   * @private
+   */
+  sendFrame(list, cb) {
+    if (list.length === 2) {
+      this._socket.cork();
+      this._socket.write(list[0]);
+      this._socket.write(list[1], cb);
+      this._socket.uncork();
+    } else {
+      this._socket.write(list[0], cb);
+    }
+  }
+}
+
+module.exports = Sender;
+
+/**
+ * Calls queued callbacks with an error.
+ *
+ * @param {Sender} sender The `Sender` instance
+ * @param {Error} err The error to call the callbacks with
+ * @param {Function} [cb] The first callback
+ * @private
+ */
+function callCallbacks(sender, err, cb) {
+  if (typeof cb === 'function') cb(err);
+
+  for (let i = 0; i < sender._queue.length; i++) {
+    const params = sender._queue[i];
+    const callback = params[params.length - 1];
+
+    if (typeof callback === 'function') callback(err);
+  }
+}
+
+/**
+ * Handles a `Sender` error.
+ *
+ * @param {Sender} sender The `Sender` instance
+ * @param {Error} err The error
+ * @param {Function} [cb] The first pending callback
+ * @private
+ */
+function onError(sender, err, cb) {
+  callCallbacks(sender, err, cb);
+  sender.onerror(err);
+}

devices/panel-preview/node_modules/ws/lib/stream.js

@@ -0,0 +1,161 @@
+/* eslint no-unused-vars: ["error", { "varsIgnorePattern": "^WebSocket$" }] */
+'use strict';
+
+const WebSocket = require('./websocket');
+const { Duplex } = require('stream');
+
+/**
+ * Emits the `'close'` event on a stream.
+ *
+ * @param {Duplex} stream The stream.
+ * @private
+ */
+function emitClose(stream) {
+  stream.emit('close');
+}
+
+/**
+ * The listener of the `'end'` event.
+ *
+ * @private
+ */
+function duplexOnEnd() {
+  if (!this.destroyed && this._writableState.finished) {
+    this.destroy();
+  }
+}
+
+/**
+ * The listener of the `'error'` event.
+ *
+ * @param {Error} err The error
+ * @private
+ */
+function duplexOnError(err) {
+  this.removeListener('error', duplexOnError);
+  this.destroy();
+  if (this.listenerCount('error') === 0) {
+    // Do not suppress the throwing behavior.
+    this.emit('error', err);
+  }
+}
+
+/**
+ * Wraps a `WebSocket` in a duplex stream.
+ *
+ * @param {WebSocket} ws The `WebSocket` to wrap
+ * @param {Object} [options] The options for the `Duplex` constructor
+ * @return {Duplex} The duplex stream
+ * @public
+ */
+function createWebSocketStream(ws, options) {
+  let terminateOnDestroy = true;
+
+  const duplex = new Duplex({
+    ...options,
+    autoDestroy: false,
+    emitClose: false,
+    objectMode: false,
+    writableObjectMode: false
+  });
+
+  ws.on('message', function message(msg, isBinary) {
+    const data =
+      !isBinary && duplex._readableState.objectMode ? msg.toString() : msg;
+
+    if (!duplex.push(data)) ws.pause();
+  });
+
+  ws.once('error', function error(err) {
+    if (duplex.destroyed) return;
+
+    // Prevent `ws.terminate()` from being called by `duplex._destroy()`.
+    //
+    // - If the `'error'` event is emitted before the `'open'` event, then
+    //   `ws.terminate()` is a noop as no socket is assigned.
+    // - Otherwise, the error is re-emitted by the listener of the `'error'`
+    //   event of the `Receiver` object. The listener already closes the
+    //   connection by calling `ws.close()`. This allows a close frame to be
+    //   sent to the other peer. If `ws.terminate()` is called right after this,
+    //   then the close frame might not be sent.
+    terminateOnDestroy = false;
+    duplex.destroy(err);
+  });
+
+  ws.once('close', function close() {
+    if (duplex.destroyed) return;
+
+    duplex.push(null);
+  });
+
+  duplex._destroy = function (err, callback) {
+    if (ws.readyState === ws.CLOSED) {
+      callback(err);
+      process.nextTick(emitClose, duplex);
+      return;
+    }
+
+    let called = false;
+
+    ws.once('error', function error(err) {
+      called = true;
+      callback(err);
+    });
+
+    ws.once('close', function close() {
+      if (!called) callback(err);
+      process.nextTick(emitClose, duplex);
+    });
+
+    if (terminateOnDestroy) ws.terminate();
+  };
+
+  duplex._final = function (callback) {
+    if (ws.readyState === ws.CONNECTING) {
+      ws.once('open', function open() {
+        duplex._final(callback);
+      });
+      return;
+    }
+
+    // If the value of the `_socket` property is `null` it means that `ws` is a
+    // client websocket and the handshake failed. In fact, when this happens, a
+    // socket is never assigned to the websocket. Wait for the `'error'` event
+    // that will be emitted by the websocket.
+    if (ws._socket === null) return;
+
+    if (ws._socket._writableState.finished) {
+      callback();
+      if (duplex._readableState.endEmitted) duplex.destroy();
+    } else {
+      ws._socket.once('finish', function finish() {
+        // `duplex` is not destroyed here because the `'end'` event will be
+        // emitted on `duplex` after this `'finish'` event. The EOF signaling
+        // `null` chunk is, in fact, pushed when the websocket emits `'close'`.
+        callback();
+      });
+      ws.close();
+    }
+  };
+
+  duplex._read = function () {
+    if (ws.isPaused) ws.resume();
+  };
+
+  duplex._write = function (chunk, encoding, callback) {
+    if (ws.readyState === ws.CONNECTING) {
+      ws.once('open', function open() {
+        duplex._write(chunk, encoding, callback);
+      });
+      return;
+    }
+
+    ws.send(chunk, callback);
+  };
+
+  duplex.on('end', duplexOnEnd);
+  duplex.on('error', duplexOnError);
+  return duplex;
+}
+
+module.exports = createWebSocketStream;

devices/panel-preview/node_modules/ws/lib/subprotocol.js

@@ -0,0 +1,62 @@
+'use strict';
+
+const { tokenChars } = require('./validation');
+
+/**
+ * Parses the `Sec-WebSocket-Protocol` header into a set of subprotocol names.
+ *
+ * @param {String} header The field value of the header
+ * @return {Set} The subprotocol names
+ * @public
+ */
+function parse(header) {
+  const protocols = new Set();
+  let start = -1;
+  let end = -1;
+  let i = 0;
+
+  for (i; i < header.length; i++) {
+    const code = header.charCodeAt(i);
+
+    if (end === -1 && tokenChars[code] === 1) {
+      if (start === -1) start = i;
+    } else if (
+      i !== 0 &&
+      (code === 0x20 /* ' ' */ || code === 0x09) /* '\t' */
+    ) {
+      if (end === -1 && start !== -1) end = i;
+    } else if (code === 0x2c /* ',' */) {
+      if (start === -1) {
+        throw new SyntaxError(`Unexpected character at index ${i}`);
+      }
+
+      if (end === -1) end = i;
+
+      const protocol = header.slice(start, end);
+
+      if (protocols.has(protocol)) {
+        throw new SyntaxError(`The "${protocol}" subprotocol is duplicated`);
+      }
+
+      protocols.add(protocol);
+      start = end = -1;
+    } else {
+      throw new SyntaxError(`Unexpected character at index ${i}`);
+    }
+  }
+
+  if (start === -1 || end !== -1) {
+    throw new SyntaxError('Unexpected end of input');
+  }
+
+  const protocol = header.slice(start, i);
+
+  if (protocols.has(protocol)) {
+    throw new SyntaxError(`The "${protocol}" subprotocol is duplicated`);
+  }
+
+  protocols.add(protocol);
+  return protocols;
+}
+
+module.exports = { parse };

devices/panel-preview/node_modules/ws/lib/validation.js

@@ -0,0 +1,152 @@
+'use strict';
+
+const { isUtf8 } = require('buffer');
+
+const { hasBlob } = require('./constants');
+
+//
+// Allowed token characters:
+//
+// '!', '#', '$', '%', '&', ''', '*', '+', '-',
+// '.', 0-9, A-Z, '^', '_', '`', a-z, '|', '~'
+//
+// tokenChars[32] === 0 // ' '
+// tokenChars[33] === 1 // '!'
+// tokenChars[34] === 0 // '"'
+// ...
+//
+// prettier-ignore
+const tokenChars = [
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 0 - 15
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 16 - 31
+  0, 1, 0, 1, 1, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 0, // 32 - 47
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, // 48 - 63
+  0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 64 - 79
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, // 80 - 95
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 96 - 111
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0 // 112 - 127
+];
+
+/**
+ * Checks if a status code is allowed in a close frame.
+ *
+ * @param {Number} code The status code
+ * @return {Boolean} `true` if the status code is valid, else `false`
+ * @public
+ */
+function isValidStatusCode(code) {
+  return (
+    (code >= 1000 &&
+      code <= 1014 &&
+      code !== 1004 &&
+      code !== 1005 &&
+      code !== 1006) ||
+    (code >= 3000 && code <= 4999)
+  );
+}
+
+/**
+ * Checks if a given buffer contains only correct UTF-8.
+ * Ported from https://www.cl.cam.ac.uk/%7Emgk25/ucs/utf8_check.c by
+ * Markus Kuhn.
+ *
+ * @param {Buffer} buf The buffer to check
+ * @return {Boolean} `true` if `buf` contains only correct UTF-8, else `false`
+ * @public
+ */
+function _isValidUTF8(buf) {
+  const len = buf.length;
+  let i = 0;
+
+  while (i < len) {
+    if ((buf[i] & 0x80) === 0) {
+      // 0xxxxxxx
+      i++;
+    } else if ((buf[i] & 0xe0) === 0xc0) {
+      // 110xxxxx 10xxxxxx
+      if (
+        i + 1 === len ||
+        (buf[i + 1] & 0xc0) !== 0x80 ||
+        (buf[i] & 0xfe) === 0xc0 // Overlong
+      ) {
+        return false;
+      }
+
+      i += 2;
+    } else if ((buf[i] & 0xf0) === 0xe0) {
+      // 1110xxxx 10xxxxxx 10xxxxxx
+      if (
+        i + 2 >= len ||
+        (buf[i + 1] & 0xc0) !== 0x80 ||
+        (buf[i + 2] & 0xc0) !== 0x80 ||
+        (buf[i] === 0xe0 && (buf[i + 1] & 0xe0) === 0x80) || // Overlong
+        (buf[i] === 0xed && (buf[i + 1] & 0xe0) === 0xa0) // Surrogate (U+D800 - U+DFFF)
+      ) {
+        return false;
+      }
+
+      i += 3;
+    } else if ((buf[i] & 0xf8) === 0xf0) {
+      // 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
+      if (
+        i + 3 >= len ||
+        (buf[i + 1] & 0xc0) !== 0x80 ||
+        (buf[i + 2] & 0xc0) !== 0x80 ||
+        (buf[i + 3] & 0xc0) !== 0x80 ||
+        (buf[i] === 0xf0 && (buf[i + 1] & 0xf0) === 0x80) || // Overlong
+        (buf[i] === 0xf4 && buf[i + 1] > 0x8f) ||
+        buf[i] > 0xf4 // > U+10FFFF
+      ) {
+        return false;
+      }
+
+      i += 4;
+    } else {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+/**
+ * Determines whether a value is a `Blob`.
+ *
+ * @param {*} value The value to be tested
+ * @return {Boolean} `true` if `value` is a `Blob`, else `false`
+ * @private
+ */
+function isBlob(value) {
+  return (
+    hasBlob &&
+    typeof value === 'object' &&
+    typeof value.arrayBuffer === 'function' &&
+    typeof value.type === 'string' &&
+    typeof value.stream === 'function' &&
+    (value[Symbol.toStringTag] === 'Blob' ||
+      value[Symbol.toStringTag] === 'File')
+  );
+}
+
+module.exports = {
+  isBlob,
+  isValidStatusCode,
+  isValidUTF8: _isValidUTF8,
+  tokenChars
+};
+
+if (isUtf8) {
+  module.exports.isValidUTF8 = function (buf) {
+    return buf.length < 24 ? _isValidUTF8(buf) : isUtf8(buf);
+  };
+} /* istanbul ignore else  */ else if (!process.env.WS_NO_UTF_8_VALIDATE) {
+  try {
+    const isValidUTF8 = require('utf-8-validate');
+
+    module.exports.isValidUTF8 = function (buf) {
+      return buf.length < 32 ? _isValidUTF8(buf) : isValidUTF8(buf);
+    };
+  } catch (e) {
+    // Continue regardless of the error.
+  }
+}

devices/panel-preview/node_modules/ws/lib/websocket-server.js

@@ -0,0 +1,554 @@
+/* eslint no-unused-vars: ["error", { "varsIgnorePattern": "^Duplex$", "caughtErrors": "none" }] */
+
+'use strict';
+
+const EventEmitter = require('events');
+const http = require('http');
+const { Duplex } = require('stream');
+const { createHash } = require('crypto');
+
+const extension = require('./extension');
+const PerMessageDeflate = require('./permessage-deflate');
+const subprotocol = require('./subprotocol');
+const WebSocket = require('./websocket');
+const { CLOSE_TIMEOUT, GUID, kWebSocket } = require('./constants');
+
+const keyRegex = /^[+/0-9A-Za-z]{22}==$/;
+
+const RUNNING = 0;
+const CLOSING = 1;
+const CLOSED = 2;
+
+/**
+ * Class representing a WebSocket server.
+ *
+ * @extends EventEmitter
+ */
+class WebSocketServer extends EventEmitter {
+  /**
+   * Create a `WebSocketServer` instance.
+   *
+   * @param {Object} options Configuration options
+   * @param {Boolean} [options.allowSynchronousEvents=true] Specifies whether
+   *     any of the `'message'`, `'ping'`, and `'pong'` events can be emitted
+   *     multiple times in the same tick
+   * @param {Boolean} [options.autoPong=true] Specifies whether or not to
+   *     automatically send a pong in response to a ping
+   * @param {Number} [options.backlog=511] The maximum length of the queue of
+   *     pending connections
+   * @param {Boolean} [options.clientTracking=true] Specifies whether or not to
+   *     track clients
+   * @param {Number} [options.closeTimeout=30000] Duration in milliseconds to
+   *     wait for the closing handshake to finish after `websocket.close()` is
+   *     called
+   * @param {Function} [options.handleProtocols] A hook to handle protocols
+   * @param {String} [options.host] The hostname where to bind the server
+   * @param {Number} [options.maxPayload=104857600] The maximum allowed message
+   *     size
+   * @param {Boolean} [options.noServer=false] Enable no server mode
+   * @param {String} [options.path] Accept only connections matching this path
+   * @param {(Boolean|Object)} [options.perMessageDeflate=false] Enable/disable
+   *     permessage-deflate
+   * @param {Number} [options.port] The port where to bind the server
+   * @param {(http.Server|https.Server)} [options.server] A pre-created HTTP/S
+   *     server to use
+   * @param {Boolean} [options.skipUTF8Validation=false] Specifies whether or
+   *     not to skip UTF-8 validation for text and close messages
+   * @param {Function} [options.verifyClient] A hook to reject connections
+   * @param {Function} [options.WebSocket=WebSocket] Specifies the `WebSocket`
+   *     class to use. It must be the `WebSocket` class or class that extends it
+   * @param {Function} [callback] A listener for the `listening` event
+   */
+  constructor(options, callback) {
+    super();
+
+    options = {
+      allowSynchronousEvents: true,
+      autoPong: true,
+      maxPayload: 100 * 1024 * 1024,
+      skipUTF8Validation: false,
+      perMessageDeflate: false,
+      handleProtocols: null,
+      clientTracking: true,
+      closeTimeout: CLOSE_TIMEOUT,
+      verifyClient: null,
+      noServer: false,
+      backlog: null, // use default (511 as implemented in net.js)
+      server: null,
+      host: null,
+      path: null,
+      port: null,
+      WebSocket,
+      ...options
+    };
+
+    if (
+      (options.port == null && !options.server && !options.noServer) ||
+      (options.port != null && (options.server || options.noServer)) ||
+      (options.server && options.noServer)
+    ) {
+      throw new TypeError(
+        'One and only one of the "port", "server", or "noServer" options ' +
+          'must be specified'
+      );
+    }
+
+    if (options.port != null) {
+      this._server = http.createServer((req, res) => {
+        const body = http.STATUS_CODES[426];
+
+        res.writeHead(426, {
+          'Content-Length': body.length,
+          'Content-Type': 'text/plain'
+        });
+        res.end(body);
+      });
+      this._server.listen(
+        options.port,
+        options.host,
+        options.backlog,
+        callback
+      );
+    } else if (options.server) {
+      this._server = options.server;
+    }
+
+    if (this._server) {
+      const emitConnection = this.emit.bind(this, 'connection');
+
+      this._removeListeners = addListeners(this._server, {
+        listening: this.emit.bind(this, 'listening'),
+        error: this.emit.bind(this, 'error'),
+        upgrade: (req, socket, head) => {
+          this.handleUpgrade(req, socket, head, emitConnection);
+        }
+      });
+    }
+
+    if (options.perMessageDeflate === true) options.perMessageDeflate = {};
+    if (options.clientTracking) {
+      this.clients = new Set();
+      this._shouldEmitClose = false;
+    }
+
+    this.options = options;
+    this._state = RUNNING;
+  }
+
+  /**
+   * Returns the bound address, the address family name, and port of the server
+   * as reported by the operating system if listening on an IP socket.
+   * If the server is listening on a pipe or UNIX domain socket, the name is
+   * returned as a string.
+   *
+   * @return {(Object|String|null)} The address of the server
+   * @public
+   */
+  address() {
+    if (this.options.noServer) {
+      throw new Error('The server is operating in "noServer" mode');
+    }
+
+    if (!this._server) return null;
+    return this._server.address();
+  }
+
+  /**
+   * Stop the server from accepting new connections and emit the `'close'` event
+   * when all existing connections are closed.
+   *
+   * @param {Function} [cb] A one-time listener for the `'close'` event
+   * @public
+   */
+  close(cb) {
+    if (this._state === CLOSED) {
+      if (cb) {
+        this.once('close', () => {
+          cb(new Error('The server is not running'));
+        });
+      }
+
+      process.nextTick(emitClose, this);
+      return;
+    }
+
+    if (cb) this.once('close', cb);
+
+    if (this._state === CLOSING) return;
+    this._state = CLOSING;
+
+    if (this.options.noServer || this.options.server) {
+      if (this._server) {
+        this._removeListeners();
+        this._removeListeners = this._server = null;
+      }
+
+      if (this.clients) {
+        if (!this.clients.size) {
+          process.nextTick(emitClose, this);
+        } else {
+          this._shouldEmitClose = true;
+        }
+      } else {
+        process.nextTick(emitClose, this);
+      }
+    } else {
+      const server = this._server;
+
+      this._removeListeners();
+      this._removeListeners = this._server = null;
+
+      //
+      // The HTTP/S server was created internally. Close it, and rely on its
+      // `'close'` event.
+      //
+      server.close(() => {
+        emitClose(this);
+      });
+    }
+  }
+
+  /**
+   * See if a given request should be handled by this server instance.
+   *
+   * @param {http.IncomingMessage} req Request object to inspect
+   * @return {Boolean} `true` if the request is valid, else `false`
+   * @public
+   */
+  shouldHandle(req) {
+    if (this.options.path) {
+      const index = req.url.indexOf('?');
+      const pathname = index !== -1 ? req.url.slice(0, index) : req.url;
+
+      if (pathname !== this.options.path) return false;
+    }
+
+    return true;
+  }
+
+  /**
+   * Handle a HTTP Upgrade request.
+   *
+   * @param {http.IncomingMessage} req The request object
+   * @param {Duplex} socket The network socket between the server and client
+   * @param {Buffer} head The first packet of the upgraded stream
+   * @param {Function} cb Callback
+   * @public
+   */
+  handleUpgrade(req, socket, head, cb) {
+    socket.on('error', socketOnError);
+
+    const key = req.headers['sec-websocket-key'];
+    const upgrade = req.headers.upgrade;
+    const version = +req.headers['sec-websocket-version'];
+
+    if (req.method !== 'GET') {
+      const message = 'Invalid HTTP method';
+      abortHandshakeOrEmitwsClientError(this, req, socket, 405, message);
+      return;
+    }
+
+    if (upgrade === undefined || upgrade.toLowerCase() !== 'websocket') {
+      const message = 'Invalid Upgrade header';
+      abortHandshakeOrEmitwsClientError(this, req, socket, 400, message);
+      return;
+    }
+
+    if (key === undefined || !keyRegex.test(key)) {
+      const message = 'Missing or invalid Sec-WebSocket-Key header';
+      abortHandshakeOrEmitwsClientError(this, req, socket, 400, message);
+      return;
+    }
+
+    if (version !== 13 && version !== 8) {
+      const message = 'Missing or invalid Sec-WebSocket-Version header';
+      abortHandshakeOrEmitwsClientError(this, req, socket, 400, message, {
+        'Sec-WebSocket-Version': '13, 8'
+      });
+      return;
+    }
+
+    if (!this.shouldHandle(req)) {
+      abortHandshake(socket, 400);
+      return;
+    }
+
+    const secWebSocketProtocol = req.headers['sec-websocket-protocol'];
+    let protocols = new Set();
+
+    if (secWebSocketProtocol !== undefined) {
+      try {
+        protocols = subprotocol.parse(secWebSocketProtocol);
+      } catch (err) {
+        const message = 'Invalid Sec-WebSocket-Protocol header';
+        abortHandshakeOrEmitwsClientError(this, req, socket, 400, message);
+        return;
+      }
+    }
+
+    const secWebSocketExtensions = req.headers['sec-websocket-extensions'];
+    const extensions = {};
+
+    if (
+      this.options.perMessageDeflate &&
+      secWebSocketExtensions !== undefined
+    ) {
+      const perMessageDeflate = new PerMessageDeflate(
+        this.options.perMessageDeflate,
+        true,
+        this.options.maxPayload
+      );
+
+      try {
+        const offers = extension.parse(secWebSocketExtensions);
+
+        if (offers[PerMessageDeflate.extensionName]) {
+          perMessageDeflate.accept(offers[PerMessageDeflate.extensionName]);
+          extensions[PerMessageDeflate.extensionName] = perMessageDeflate;
+        }
+      } catch (err) {
+        const message =
+          'Invalid or unacceptable Sec-WebSocket-Extensions header';
+        abortHandshakeOrEmitwsClientError(this, req, socket, 400, message);
+        return;
+      }
+    }
+
+    //
+    // Optionally call external client verification handler.
+    //
+    if (this.options.verifyClient) {
+      const info = {
+        origin:
+          req.headers[`${version === 8 ? 'sec-websocket-origin' : 'origin'}`],
+        secure: !!(req.socket.authorized || req.socket.encrypted),
+        req
+      };
+
+      if (this.options.verifyClient.length === 2) {
+        this.options.verifyClient(info, (verified, code, message, headers) => {
+          if (!verified) {
+            return abortHandshake(socket, code || 401, message, headers);
+          }
+
+          this.completeUpgrade(
+            extensions,
+            key,
+            protocols,
+            req,
+            socket,
+            head,
+            cb
+          );
+        });
+        return;
+      }
+
+      if (!this.options.verifyClient(info)) return abortHandshake(socket, 401);
+    }
+
+    this.completeUpgrade(extensions, key, protocols, req, socket, head, cb);
+  }
+
+  /**
+   * Upgrade the connection to WebSocket.
+   *
+   * @param {Object} extensions The accepted extensions
+   * @param {String} key The value of the `Sec-WebSocket-Key` header
+   * @param {Set} protocols The subprotocols
+   * @param {http.IncomingMessage} req The request object
+   * @param {Duplex} socket The network socket between the server and client
+   * @param {Buffer} head The first packet of the upgraded stream
+   * @param {Function} cb Callback
+   * @throws {Error} If called more than once with the same socket
+   * @private
+   */
+  completeUpgrade(extensions, key, protocols, req, socket, head, cb) {
+    //
+    // Destroy the socket if the client has already sent a FIN packet.
+    //
+    if (!socket.readable || !socket.writable) return socket.destroy();
+
+    if (socket[kWebSocket]) {
+      throw new Error(
+        'server.handleUpgrade() was called more than once with the same ' +
+          'socket, possibly due to a misconfiguration'
+      );
+    }
+
+    if (this._state > RUNNING) return abortHandshake(socket, 503);
+
+    const digest = createHash('sha1')
+      .update(key + GUID)
+      .digest('base64');
+
+    const headers = [
+      'HTTP/1.1 101 Switching Protocols',
+      'Upgrade: websocket',
+      'Connection: Upgrade',
+      `Sec-WebSocket-Accept: ${digest}`
+    ];
+
+    const ws = new this.options.WebSocket(null, undefined, this.options);
+
+    if (protocols.size) {
+      //
+      // Optionally call external protocol selection handler.
+      //
+      const protocol = this.options.handleProtocols
+        ? this.options.handleProtocols(protocols, req)
+        : protocols.values().next().value;
+
+      if (protocol) {
+        headers.push(`Sec-WebSocket-Protocol: ${protocol}`);
+        ws._protocol = protocol;
+      }
+    }
+
+    if (extensions[PerMessageDeflate.extensionName]) {
+      const params = extensions[PerMessageDeflate.extensionName].params;
+      const value = extension.format({
+        [PerMessageDeflate.extensionName]: [params]
+      });
+      headers.push(`Sec-WebSocket-Extensions: ${value}`);
+      ws._extensions = extensions;
+    }
+
+    //
+    // Allow external modification/inspection of handshake headers.
+    //
+    this.emit('headers', headers, req);
+
+    socket.write(headers.concat('\r\n').join('\r\n'));
+    socket.removeListener('error', socketOnError);
+
+    ws.setSocket(socket, head, {
+      allowSynchronousEvents: this.options.allowSynchronousEvents,
+      maxPayload: this.options.maxPayload,
+      skipUTF8Validation: this.options.skipUTF8Validation
+    });
+
+    if (this.clients) {
+      this.clients.add(ws);
+      ws.on('close', () => {
+        this.clients.delete(ws);
+
+        if (this._shouldEmitClose && !this.clients.size) {
+          process.nextTick(emitClose, this);
+        }
+      });
+    }
+
+    cb(ws, req);
+  }
+}
+
+module.exports = WebSocketServer;
+
+/**
+ * Add event listeners on an `EventEmitter` using a map of <event, listener>
+ * pairs.
+ *
+ * @param {EventEmitter} server The event emitter
+ * @param {Object.<String, Function>} map The listeners to add
+ * @return {Function} A function that will remove the added listeners when
+ *     called
+ * @private
+ */
+function addListeners(server, map) {
+  for (const event of Object.keys(map)) server.on(event, map[event]);
+
+  return function removeListeners() {
+    for (const event of Object.keys(map)) {
+      server.removeListener(event, map[event]);
+    }
+  };
+}
+
+/**
+ * Emit a `'close'` event on an `EventEmitter`.
+ *
+ * @param {EventEmitter} server The event emitter
+ * @private
+ */
+function emitClose(server) {
+  server._state = CLOSED;
+  server.emit('close');
+}
+
+/**
+ * Handle socket errors.
+ *
+ * @private
+ */
+function socketOnError() {
+  this.destroy();
+}
+
+/**
+ * Close the connection when preconditions are not fulfilled.
+ *
+ * @param {Duplex} socket The socket of the upgrade request
+ * @param {Number} code The HTTP response status code
+ * @param {String} [message] The HTTP response body
+ * @param {Object} [headers] Additional HTTP response headers
+ * @private
+ */
+function abortHandshake(socket, code, message, headers) {
+  //
+  // The socket is writable unless the user destroyed or ended it before calling
+  // `server.handleUpgrade()` or in the `verifyClient` function, which is a user
+  // error. Handling this does not make much sense as the worst that can happen
+  // is that some of the data written by the user might be discarded due to the
+  // call to `socket.end()` below, which triggers an `'error'` event that in
+  // turn causes the socket to be destroyed.
+  //
+  message = message || http.STATUS_CODES[code];
+  headers = {
+    Connection: 'close',
+    'Content-Type': 'text/html',
+    'Content-Length': Buffer.byteLength(message),
+    ...headers
+  };
+
+  socket.once('finish', socket.destroy);
+
+  socket.end(
+    `HTTP/1.1 ${code} ${http.STATUS_CODES[code]}\r\n` +
+      Object.keys(headers)
+        .map((h) => `${h}: ${headers[h]}`)
+        .join('\r\n') +
+      '\r\n\r\n' +
+      message
+  );
+}
+
+/**
+ * Emit a `'wsClientError'` event on a `WebSocketServer` if there is at least
+ * one listener for it, otherwise call `abortHandshake()`.
+ *
+ * @param {WebSocketServer} server The WebSocket server
+ * @param {http.IncomingMessage} req The request object
+ * @param {Duplex} socket The socket of the upgrade request
+ * @param {Number} code The HTTP response status code
+ * @param {String} message The HTTP response body
+ * @param {Object} [headers] The HTTP response headers
+ * @private
+ */
+function abortHandshakeOrEmitwsClientError(
+  server,
+  req,
+  socket,
+  code,
+  message,
+  headers
+) {
+  if (server.listenerCount('wsClientError')) {
+    const err = new Error(message);
+    Error.captureStackTrace(err, abortHandshakeOrEmitwsClientError);
+
+    server.emit('wsClientError', err, socket, req);
+  } else {
+    abortHandshake(socket, code, message, headers);
+  }
+}

devices/panel-preview/node_modules/ws/package.json

@@ -0,0 +1,69 @@
+{
+  "name": "ws",
+  "version": "8.19.0",
+  "description": "Simple to use, blazing fast and thoroughly tested websocket client and server for Node.js",
+  "keywords": [
+    "HyBi",
+    "Push",
+    "RFC-6455",
+    "WebSocket",
+    "WebSockets",
+    "real-time"
+  ],
+  "homepage": "https://github.com/websockets/ws",
+  "bugs": "https://github.com/websockets/ws/issues",
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/websockets/ws.git"
+  },
+  "author": "Einar Otto Stangvik <einaros@gmail.com> (http://2x.io)",
+  "license": "MIT",
+  "main": "index.js",
+  "exports": {
+    ".": {
+      "browser": "./browser.js",
+      "import": "./wrapper.mjs",
+      "require": "./index.js"
+    },
+    "./package.json": "./package.json"
+  },
+  "browser": "browser.js",
+  "engines": {
+    "node": ">=10.0.0"
+  },
+  "files": [
+    "browser.js",
+    "index.js",
+    "lib/*.js",
+    "wrapper.mjs"
+  ],
+  "scripts": {
+    "test": "nyc --reporter=lcov --reporter=text mocha --throw-deprecation test/*.test.js",
+    "integration": "mocha --throw-deprecation test/*.integration.js",
+    "lint": "eslint . && prettier --check --ignore-path .gitignore \"**/*.{json,md,yaml,yml}\""
+  },
+  "peerDependencies": {
+    "bufferutil": "^4.0.1",
+    "utf-8-validate": ">=5.0.2"
+  },
+  "peerDependenciesMeta": {
+    "bufferutil": {
+      "optional": true
+    },
+    "utf-8-validate": {
+      "optional": true
+    }
+  },
+  "devDependencies": {
+    "benchmark": "^2.1.4",
+    "bufferutil": "^4.0.1",
+    "eslint": "^9.0.0",
+    "eslint-config-prettier": "^10.0.1",
+    "eslint-plugin-prettier": "^5.0.0",
+    "globals": "^16.0.0",
+    "mocha": "^8.4.0",
+    "nyc": "^15.0.0",
+    "prettier": "^3.0.0",
+    "utf-8-validate": "^6.0.0"
+  }
+}

devices/panel-preview/node_modules/ws/wrapper.mjs

@@ -0,0 +1,8 @@
+import createWebSocketStream from './lib/stream.js';
+import Receiver from './lib/receiver.js';
+import Sender from './lib/sender.js';
+import WebSocket from './lib/websocket.js';
+import WebSocketServer from './lib/websocket-server.js';
+
+export { createWebSocketStream, Receiver, Sender, WebSocket, WebSocketServer };
+export default WebSocket;

devices/panel-preview/package-lock.json

@@ -0,0 +1,37 @@
+{
+  "name": "panel-preview",
+  "version": "1.0.0",
+  "lockfileVersion": 3,
+  "requires": true,
+  "packages": {
+    "": {
+      "name": "panel-preview",
+      "version": "1.0.0",
+      "license": "ISC",
+      "dependencies": {
+        "ws": "^8.19.0"
+      }
+    },
+    "node_modules/ws": {
+      "version": "8.19.0",
+      "resolved": "https://registry.npmjs.org/ws/-/ws-8.19.0.tgz",
+      "integrity": "sha512-blAT2mjOEIi0ZzruJfIhb3nps74PRWTCz1IjglWEEpQl5XS/UNama6u2/rjFkDDouqr4L67ry+1aGIALViWjDg==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=10.0.0"
+      },
+      "peerDependencies": {
+        "bufferutil": "^4.0.1",
+        "utf-8-validate": ">=5.0.2"
+      },
+      "peerDependenciesMeta": {
+        "bufferutil": {
+          "optional": true
+        },
+        "utf-8-validate": {
+          "optional": true
+        }
+      }
+    }
+  }
+}

devices/panel-preview/package.json

@@ -0,0 +1,15 @@
+{
+  "name": "panel-preview",
+  "version": "1.0.0",
+  "main": "relay-bridge.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "description": "",
+  "dependencies": {
+    "ws": "^8.19.0"
+  }
+}

devices/panel-preview/relay-bridge.js

@@ -0,0 +1,139 @@
+#!/usr/bin/env node
+/**
+ * DreamStack Relay Bridge — UDP ↔ WebSocket
+ *
+ * Bridges the hub's UDP binary frames to the browser previewer
+ * via WebSocket. This lets you test the full signal pipeline
+ * without ESP32 hardware.
+ *
+ * Architecture:
+ *   ds-hub (Rust) → UDP:9200 → [this relay] → WS:9201 → browser previewer
+ *   browser → WS:9201 → [this relay] → UDP:9200 → ds-hub
+ *
+ * Usage:
+ *   node relay-bridge.js
+ *   Then open previewer with: ?ws=ws://localhost:9201
+ */
+
+const dgram = require('dgram');
+const { WebSocketServer } = require('ws');
+const http = require('http');
+const fs = require('fs');
+const path = require('path');
+
+const UDP_PORT = 9200;
+const WS_PORT = 9201;
+const HTTP_PORT = 9876;  // Serve previewer HTML too
+
+// ─── WebSocket Server ───
+const wss = new WebSocketServer({ host: '0.0.0.0', port: WS_PORT });
+const clients = new Set();
+
+wss.on('connection', (ws, req) => {
+    clients.add(ws);
+    console.log(`[WS] Client connected (${clients.size} total)`);
+
+    ws.on('message', (data) => {
+        // Forward binary messages from browser → UDP (hub)
+        if (Buffer.isBuffer(data) || data instanceof ArrayBuffer) {
+            const buf = Buffer.from(data);
+            udp.send(buf, 0, buf.length, UDP_PORT, '127.0.0.1', (err) => {
+                if (err) console.error('[UDP] Send error:', err);
+            });
+        }
+    });
+
+    ws.on('close', () => {
+        clients.delete(ws);
+        console.log(`[WS] Client disconnected (${clients.size} remaining)`);
+    });
+
+    // If we have a cached IR, send it immediately
+    if (cachedIR) {
+        ws.send(cachedIR);
+        console.log('[WS] Sent cached IR to new client');
+    }
+});
+
+// ─── UDP Receiver ───
+const udp = dgram.createSocket('udp4');
+let cachedIR = null;  // Cache latest IR push for new WS clients
+let hubAddr = null;   // Remember hub address for replies
+
+udp.on('message', (msg, rinfo) => {
+    hubAddr = rinfo;
+
+    // Check if this is an IR push (has magic bytes + IR type)
+    if (msg.length >= 6 && msg[0] === 0xD5 && msg[1] === 0x7A && msg[2] === 0x40) {
+        // Extract and cache the IR JSON
+        const len = msg.readUInt16LE(4);
+        const json = msg.slice(6, 6 + len).toString();
+        cachedIR = json;
+        console.log(`[UDP] IR push received (${len} bytes), broadcasting to ${clients.size} WS clients`);
+
+        // Send as JSON text to all WS clients
+        for (const ws of clients) {
+            if (ws.readyState === 1) ws.send(json);
+        }
+        return;
+    }
+
+    // Forward all other binary frames to WS clients
+    for (const ws of clients) {
+        if (ws.readyState === 1) ws.send(msg);
+    }
+
+    // Log signal updates
+    if (msg[0] === 0x20 && msg.length >= 7) {
+        const sigId = msg.readUInt16LE(1);
+        const value = msg.readInt32LE(3);
+        // Only log occasionally to avoid spam
+        if (sigId === 0 || value % 10 === 0) {
+            console.log(`[UDP] Signal ${sigId} = ${value}`);
+        }
+    }
+});
+
+udp.on('error', (err) => {
+    console.error('[UDP] Error:', err);
+});
+
+udp.bind(UDP_PORT, () => {
+    console.log(`[UDP] Listening on port ${UDP_PORT}`);
+});
+
+// ─── HTTP Server (serve previewer) ───
+const server = http.createServer((req, res) => {
+    let filePath = path.join(__dirname, req.url === '/' ? 'index.html' : req.url.split('?')[0]);
+
+    if (!fs.existsSync(filePath)) {
+        res.writeHead(404);
+        res.end('Not found');
+        return;
+    }
+
+    const ext = path.extname(filePath);
+    const contentType = {
+        '.html': 'text/html',
+        '.js': 'application/javascript',
+        '.css': 'text/css',
+        '.json': 'application/json',
+        '.png': 'image/png',
+    }[ext] || 'application/octet-stream';
+
+    res.writeHead(200, { 'Content-Type': contentType });
+    fs.createReadStream(filePath).pipe(res);
+});
+
+server.listen(HTTP_PORT, '0.0.0.0', () => {
+    console.log(`\n  DreamStack Relay Bridge`);
+    console.log(`  ─────────────────────────`);
+    console.log(`  HTTP:       http://localhost:${HTTP_PORT}/`);
+    console.log(`  WebSocket:  ws://localhost:${WS_PORT}`);
+    console.log(`  UDP:        port ${UDP_PORT}`);
+    console.log(`\n  Open previewer in live mode:`);
+    console.log(`  http://localhost:${HTTP_PORT}/index.html?ws=ws://localhost:${WS_PORT}`);
+    console.log(`\n  Or file mode (no hub needed):`);
+    console.log(`  http://localhost:${HTTP_PORT}/index.html`);
+    console.log('');
+});

devices/panel-preview/test-hub.js

@@ -0,0 +1,96 @@
+#!/usr/bin/env node
+/**
+ * Test script — simulates a hub sending signals to the relay bridge.
+ *
+ * Usage:
+ *   1. Start relay:  node relay-bridge.js
+ *   2. Open browser: http://localhost:9876/index.html?ws=ws://localhost:9201
+ *   3. Run this:     node test-hub.js
+ *
+ * This will:
+ *   1. Push IR JSON (from app.ir.json) via UDP
+ *   2. Send signal updates every 250ms
+ *   3. Listen for panel events (action/touch)
+ */
+
+const dgram = require('dgram');
+const fs = require('fs');
+const path = require('path');
+
+const UDP_PORT = 9200;
+const client = dgram.createSocket('udp4');
+
+// ─── Push IR JSON ───
+const irPath = path.join(__dirname, 'app.ir.json');
+if (fs.existsSync(irPath)) {
+    const json = fs.readFileSync(irPath, 'utf8');
+    const data = Buffer.from(json);
+
+    // Build IR push frame: [D5][7A][40][00][len:u16LE][json...]
+    const header = Buffer.alloc(6);
+    header[0] = 0xD5;  // magic
+    header[1] = 0x7A;  // magic
+    header[2] = 0x40;  // DS_UDP_IR_PUSH
+    header[3] = 0x00;  // reserved
+    header.writeUInt16LE(data.length, 4);
+
+    const frame = Buffer.concat([header, data]);
+    client.send(frame, 0, frame.length, UDP_PORT, '127.0.0.1', () => {
+        console.log(`[Hub] IR pushed (${data.length} bytes)`);
+    });
+} else {
+    console.log('[Hub] No app.ir.json found, skipping IR push');
+}
+
+// ─── Send periodic signal updates ───
+let tick = 0;
+
+setInterval(() => {
+    tick++;
+
+    // Signal 6 (ticks) — increment every second
+    if (tick % 4 === 0) {
+        const sigFrame = Buffer.alloc(7);
+        sigFrame[0] = 0x20;  // DS_NOW_SIG
+        sigFrame.writeUInt16LE(6, 1);  // signal_id = 6
+        sigFrame.writeInt32LE(Math.floor(tick / 4), 3);  // value = seconds
+        client.send(sigFrame, 0, 7, UDP_PORT, '127.0.0.1');
+    }
+
+    // Signal 2 (score) — increment every 10 ticks
+    if (tick % 40 === 0) {
+        const sigFrame = Buffer.alloc(7);
+        sigFrame[0] = 0x20;
+        sigFrame.writeUInt16LE(2, 1);  // signal_id = 2 (score)
+        sigFrame.writeInt32LE(Math.floor(tick / 40), 3);
+        client.send(sigFrame, 0, 7, UDP_PORT, '127.0.0.1');
+        console.log(`[Hub] Score → ${Math.floor(tick / 40)}`);
+    }
+
+    // Batch update: signals 0,1 (head position) every 250ms
+    if (tick % 1 === 0) {
+        const batchFrame = Buffer.alloc(3 + 2 * 6);  // 2 entries
+        batchFrame[0] = 0x21;  // DS_NOW_SIG_BATCH
+        batchFrame[1] = 2;     // count
+        batchFrame[2] = tick & 0xFF;  // seq
+
+        // Signal 0 (headX)
+        batchFrame.writeUInt16LE(0, 3);
+        batchFrame.writeInt32LE(4 + (tick % 8), 5);
+
+        // Signal 1 (headY)
+        batchFrame.writeUInt16LE(1, 9);
+        batchFrame.writeInt32LE(4, 11);
+
+        client.send(batchFrame, 0, batchFrame.length, UDP_PORT, '127.0.0.1');
+    }
+}, 250);
+
+// ─── Listen for events from panel/browser ───
+const listener = dgram.createSocket('udp4');
+// Note: relay bridge sends events back to the source address,
+// so we'd need to be listening on the same port. For testing,
+// the relay bridge console logs will show events.
+
+console.log('[Hub] Sending signals every 250ms...');
+console.log('[Hub] Press Ctrl+C to stop');

devices/waveshare-p4-panel/main/CMakeLists.txt

@@ -1,5 +1,5 @@
 idf_component_register(
-    SRCS "main.c" "ds_codec.c"
+    SRCS "main.c" "ds_codec.c" "ds_espnow.c" "ds_runtime.c"
     INCLUDE_DIRS "."
     REQUIRES
         esp_wifi
@@ -8,4 +8,6 @@ idf_component_register(
         esp_timer
         nvs_flash
         esp_psram
+        esp_now
+        lwip
 )

devices/waveshare-p4-panel/main/ds_espnow.c

@@ -0,0 +1,248 @@
+/**
+ * DreamStack ESP-NOW Transport — Implementation
+ *
+ * Handles ESP-NOW receive/send for binary signal frames,
+ * and UDP listener for IR JSON push.
+ */
+
+#include <string.h>
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include "esp_log.h"
+#include "esp_wifi.h"
+#include "esp_now.h"
+#include "lwip/sockets.h"
+
+#include "ds_espnow.h"
+
+static const char *TAG = "ds-espnow";
+
+// ─── State ───
+static ds_espnow_config_t s_config;
+static uint8_t s_seq = 0;
+static int s_udp_sock = -1;
+static TaskHandle_t s_udp_task = NULL;
+
+// ─── IR fragment reassembly ───
+#define MAX_IR_SIZE 16384
+static uint8_t s_ir_buf[MAX_IR_SIZE];
+static size_t  s_ir_len = 0;
+static uint8_t s_frag_received = 0;
+static uint8_t s_frag_total = 0;
+static uint8_t s_frag_seq = 0xFF;
+
+// ─── ESP-NOW Receive Callback ───
+static void espnow_recv_cb(const esp_now_recv_info_t *recv_info,
+                            const uint8_t *data, int len) {
+    if (len < 1) return;
+
+    uint8_t type = data[0];
+
+    switch (type) {
+    case DS_NOW_SIG:
+        if (len >= sizeof(ds_sig_frame_t)) {
+            const ds_sig_frame_t *f = (const ds_sig_frame_t *)data;
+            if (s_config.on_signal) {
+                s_config.on_signal(f->signal_id, f->value);
+            }
+        }
+        break;
+
+    case DS_NOW_SIG_BATCH:
+        if (len >= sizeof(ds_sig_batch_t)) {
+            const ds_sig_batch_t *b = (const ds_sig_batch_t *)data;
+            const ds_sig_entry_t *entries = (const ds_sig_entry_t *)(data + sizeof(ds_sig_batch_t));
+            size_t expected = sizeof(ds_sig_batch_t) + b->count * sizeof(ds_sig_entry_t);
+            if (len >= expected && s_config.on_signal) {
+                for (int i = 0; i < b->count; i++) {
+                    s_config.on_signal(entries[i].id, entries[i].val);
+                }
+            }
+        }
+        break;
+
+    case DS_NOW_PING: {
+        // Respond with pong
+        ds_heartbeat_t pong = { .type = DS_NOW_PONG, .seq = data[1] };
+        esp_now_send(recv_info->src_addr, (const uint8_t *)&pong, sizeof(pong));
+        break;
+    }
+
+    case DS_NOW_PONG:
+        ESP_LOGD(TAG, "Pong received (seq=%d)", data[1]);
+        break;
+
+    default:
+        ESP_LOGW(TAG, "Unknown ESP-NOW frame type: 0x%02x", type);
+        break;
+    }
+}
+
+// ─── ESP-NOW Send Callback ───
+static void espnow_send_cb(const uint8_t *mac_addr, esp_now_send_status_t status) {
+    if (status != ESP_NOW_SEND_SUCCESS) {
+        ESP_LOGW(TAG, "ESP-NOW send failed");
+    }
+}
+
+// ─── UDP Listener Task ───
+// Receives IR JSON push and fragmented IR over UDP
+static void udp_listener_task(void *arg) {
+    struct sockaddr_in addr = {
+        .sin_family = AF_INET,
+        .sin_port = htons(DS_UDP_PORT),
+        .sin_addr.s_addr = htonl(INADDR_ANY),
+    };
+
+    s_udp_sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+    if (s_udp_sock < 0) {
+        ESP_LOGE(TAG, "Failed to create UDP socket");
+        vTaskDelete(NULL);
+        return;
+    }
+
+    if (bind(s_udp_sock, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
+        ESP_LOGE(TAG, "Failed to bind UDP port %d", DS_UDP_PORT);
+        close(s_udp_sock);
+        s_udp_sock = -1;
+        vTaskDelete(NULL);
+        return;
+    }
+
+    ESP_LOGI(TAG, "UDP listener on port %d", DS_UDP_PORT);
+
+    uint8_t buf[1500];
+    while (1) {
+        int len = recvfrom(s_udp_sock, buf, sizeof(buf), 0, NULL, NULL);
+        if (len < 4) continue;
+
+        // Check magic
+        if (buf[0] != 0xD5 || buf[1] != 0x7A) continue;
+
+        uint8_t frame_type = buf[2];
+
+        if (frame_type == DS_UDP_IR_PUSH) {
+            // Non-fragmented IR push
+            const ds_ir_push_t *hdr = (const ds_ir_push_t *)buf;
+            size_t json_len = hdr->length;
+            if (json_len <= len - sizeof(ds_ir_push_t) && json_len < MAX_IR_SIZE) {
+                memcpy(s_ir_buf, buf + sizeof(ds_ir_push_t), json_len);
+                s_ir_buf[json_len] = '\0';
+                ESP_LOGI(TAG, "IR push received (%zu bytes)", json_len);
+                if (s_config.on_ir_push) {
+                    s_config.on_ir_push((const char *)s_ir_buf, json_len);
+                }
+            }
+        } else if (frame_type == DS_UDP_IR_FRAG) {
+            // Fragmented IR push
+            if (len < sizeof(ds_ir_frag_t)) continue;
+            const ds_ir_frag_t *frag = (const ds_ir_frag_t *)buf;
+            size_t payload_len = len - sizeof(ds_ir_frag_t);
+            const uint8_t *payload = buf + sizeof(ds_ir_frag_t);
+
+            // New fragment group?
+            if (frag->seq != s_frag_seq) {
+                s_frag_seq = frag->seq;
+                s_frag_received = 0;
+                s_frag_total = frag->frag_total;
+                s_ir_len = 0;
+            }
+
+            // Append fragment (assume ordered delivery)
+            if (s_ir_len + payload_len < MAX_IR_SIZE) {
+                memcpy(s_ir_buf + s_ir_len, payload, payload_len);
+                s_ir_len += payload_len;
+                s_frag_received++;
+
+                if (s_frag_received >= s_frag_total) {
+                    s_ir_buf[s_ir_len] = '\0';
+                    ESP_LOGI(TAG, "IR reassembled (%zu bytes, %d frags)",
+                             s_ir_len, s_frag_total);
+                    if (s_config.on_ir_push) {
+                        s_config.on_ir_push((const char *)s_ir_buf, s_ir_len);
+                    }
+                }
+            }
+        }
+    }
+}
+
+// ─── Public API ───
+
+esp_err_t ds_espnow_init(const ds_espnow_config_t *config) {
+    s_config = *config;
+    if (s_config.channel == 0) s_config.channel = DS_ESPNOW_CHANNEL;
+
+    // Initialize ESP-NOW
+    esp_err_t ret = esp_now_init();
+    if (ret != ESP_OK) {
+        ESP_LOGE(TAG, "ESP-NOW init failed: %s", esp_err_to_name(ret));
+        return ret;
+    }
+
+    esp_now_register_recv_cb(espnow_recv_cb);
+    esp_now_register_send_cb(espnow_send_cb);
+
+    // Add hub as peer
+    esp_now_peer_info_t peer = {
+        .channel = s_config.channel,
+        .ifidx = WIFI_IF_STA,
+        .encrypt = false,
+    };
+    memcpy(peer.peer_addr, s_config.hub_mac, 6);
+    ret = esp_now_add_peer(&peer);
+    if (ret != ESP_OK) {
+        ESP_LOGW(TAG, "Add peer failed (may already exist): %s", esp_err_to_name(ret));
+    }
+
+    ESP_LOGI(TAG, "ESP-NOW initialized (ch=%d, hub=%02x:%02x:%02x:%02x:%02x:%02x)",
+             s_config.channel,
+             s_config.hub_mac[0], s_config.hub_mac[1], s_config.hub_mac[2],
+             s_config.hub_mac[3], s_config.hub_mac[4], s_config.hub_mac[5]);
+
+    // Start UDP listener
+    xTaskCreate(udp_listener_task, "ds_udp", 4096, NULL, 5, &s_udp_task);
+
+    return ESP_OK;
+}
+
+esp_err_t ds_espnow_send_action(uint8_t node_id, uint8_t action) {
+    ds_action_frame_t frame = {
+        .type = DS_NOW_ACTION,
+        .node_id = node_id,
+        .action = action,
+        .seq = s_seq++,
+    };
+    return esp_now_send(s_config.hub_mac, (const uint8_t *)&frame, sizeof(frame));
+}
+
+esp_err_t ds_espnow_send_touch(uint8_t node_id, uint8_t event,
+                                uint16_t x, uint16_t y) {
+    ds_touch_now_t frame = {
+        .type = DS_NOW_TOUCH,
+        .node_id = node_id,
+        .event = event,
+        .seq = s_seq++,
+        .x = x,
+        .y = y,
+    };
+    return esp_now_send(s_config.hub_mac, (const uint8_t *)&frame, sizeof(frame));
+}
+
+esp_err_t ds_espnow_send_ping(void) {
+    ds_heartbeat_t ping = { .type = DS_NOW_PING, .seq = s_seq++ };
+    return esp_now_send(s_config.hub_mac, (const uint8_t *)&ping, sizeof(ping));
+}
+
+void ds_espnow_deinit(void) {
+    if (s_udp_task) {
+        vTaskDelete(s_udp_task);
+        s_udp_task = NULL;
+    }
+    if (s_udp_sock >= 0) {
+        close(s_udp_sock);
+        s_udp_sock = -1;
+    }
+    esp_now_deinit();
+    ESP_LOGI(TAG, "ESP-NOW deinitialized");
+}

devices/waveshare-p4-panel/main/ds_espnow.h

@@ -0,0 +1,143 @@
+/**
+ * DreamStack ESP-NOW Transport — Ultra-Low Latency Binary Protocol
+ *
+ * Sub-1ms signal delivery over ESP-NOW (WiFi direct, no router).
+ * Binary packed frames instead of JSON for minimal overhead.
+ *
+ * Transport strategy:
+ *   ESP-NOW: real-time signals + events (<1ms, ≤250 bytes)
+ *   UDP:     initial IR push + large payloads (~2ms, ≤1472 bytes)
+ */
+
+#pragma once
+#include <stdint.h>
+#include <stdbool.h>
+#include "esp_now.h"
+
+// ─── ESP-NOW Frame Types ───
+#define DS_NOW_SIG           0x20  // Single signal update (hub → panel)
+#define DS_NOW_SIG_BATCH     0x21  // Batch signal update (hub → panel)
+#define DS_NOW_TOUCH         0x30  // Touch event (panel → hub)
+#define DS_NOW_ACTION        0x31  // Button/widget action (panel → hub)
+#define DS_NOW_PING          0xFE  // Heartbeat (bidirectional)
+#define DS_NOW_PONG          0xFD  // Heartbeat response
+
+// ─── UDP Frame Types ───
+#define DS_UDP_IR_PUSH       0x40  // Full IR JSON push (hub → panel)
+#define DS_UDP_IR_FRAG       0x41  // IR fragment for payloads > MTU
+#define DS_UDP_DISCOVER      0x42  // Panel discovery broadcast
+
+// ─── UDP Port ───
+#define DS_UDP_PORT          9200
+
+// ─── ESP-NOW Channel ───
+#define DS_ESPNOW_CHANNEL   1
+
+// ─── Max ESP-NOW payload ───
+#define DS_ESPNOW_MAX_DATA  250
+
+// ─── Signal Update Frame (7 bytes) ───
+// Hub → Panel: update a single signal value
+typedef struct __attribute__((packed)) {
+    uint8_t  type;        // DS_NOW_SIG
+    uint16_t signal_id;   // which signal (0-65535)
+    int32_t  value;       // new value
+} ds_sig_frame_t;
+
+// ─── Signal Batch Frame (3 + 6*N bytes) ───
+// Hub → Panel: update multiple signals at once
+typedef struct __attribute__((packed)) {
+    uint16_t id;
+    int32_t  val;
+} ds_sig_entry_t;
+
+typedef struct __attribute__((packed)) {
+    uint8_t  type;        // DS_NOW_SIG_BATCH
+    uint8_t  count;       // number of signals (max ~40 in 250B)
+    uint8_t  seq;         // sequence number (wrapping u8)
+    // followed by `count` ds_sig_entry_t entries
+} ds_sig_batch_t;
+
+// ─── Touch Event Frame (8 bytes) ───
+// Panel → Hub: touch on the display
+typedef struct __attribute__((packed)) {
+    uint8_t  type;        // DS_NOW_TOUCH
+    uint8_t  node_id;     // which UI node (from IR)
+    uint8_t  event;       // 0=click, 1=long_press, 2=release, 3=drag
+    uint8_t  seq;         // sequence number
+    uint16_t x;           // touch X coordinate
+    uint16_t y;           // touch Y coordinate
+} ds_touch_now_t;
+
+// ─── Action Event Frame (4 bytes) ───
+// Panel → Hub: widget action (button click, toggle, etc.)
+typedef struct __attribute__((packed)) {
+    uint8_t  type;        // DS_NOW_ACTION
+    uint8_t  node_id;     // which widget
+    uint8_t  action;      // 0=click, 1=toggle, 2=slide_change
+    uint8_t  seq;         // sequence number
+} ds_action_frame_t;
+
+// ─── Heartbeat Frame (2 bytes) ───
+typedef struct __attribute__((packed)) {
+    uint8_t  type;        // DS_NOW_PING or DS_NOW_PONG
+    uint8_t  seq;         // echo back on pong
+} ds_heartbeat_t;
+
+// ─── UDP IR Push Header (4 bytes + payload) ───
+typedef struct __attribute__((packed)) {
+    uint8_t  magic[2];    // 0xD5, 0x7A
+    uint16_t length;      // JSON payload length
+    // followed by `length` bytes of IR JSON
+} ds_ir_push_t;
+
+// ─── UDP IR Fragment Header (6 bytes + payload) ───
+typedef struct __attribute__((packed)) {
+    uint8_t  magic[2];    // 0xD5, 0x7A
+    uint8_t  type;        // DS_UDP_IR_FRAG
+    uint8_t  frag_id;     // fragment index (0-based)
+    uint8_t  frag_total;  // total fragments
+    uint8_t  seq;         // group sequence
+    // followed by fragment data (up to 1466 bytes)
+} ds_ir_frag_t;
+
+// ─── Callbacks ───
+typedef void (*ds_signal_cb_t)(uint16_t signal_id, int32_t value);
+typedef void (*ds_ir_cb_t)(const char *ir_json, size_t length);
+
+// ─── Configuration ───
+typedef struct {
+    uint8_t         hub_mac[6];     // Hub MAC address (set to FF:FF:FF:FF:FF:FF for broadcast)
+    uint8_t         channel;        // WiFi channel (default: DS_ESPNOW_CHANNEL)
+    ds_signal_cb_t  on_signal;      // Called when a signal update arrives
+    ds_ir_cb_t      on_ir_push;     // Called when a full IR JSON arrives
+} ds_espnow_config_t;
+
+/**
+ * Initialize ESP-NOW transport.
+ * Sets up ESP-NOW, registers peer, starts UDP listener.
+ * WiFi must be initialized first (STA or AP mode, no connection needed).
+ */
+esp_err_t ds_espnow_init(const ds_espnow_config_t *config);
+
+/**
+ * Send an action event to the hub (panel → hub).
+ * Encodes as ds_action_frame_t and sends via ESP-NOW.
+ */
+esp_err_t ds_espnow_send_action(uint8_t node_id, uint8_t action);
+
+/**
+ * Send a touch event to the hub (panel → hub).
+ */
+esp_err_t ds_espnow_send_touch(uint8_t node_id, uint8_t event,
+                                uint16_t x, uint16_t y);
+
+/**
+ * Send a heartbeat ping.
+ */
+esp_err_t ds_espnow_send_ping(void);
+
+/**
+ * Deinitialize ESP-NOW transport.
+ */
+void ds_espnow_deinit(void);

devices/waveshare-p4-panel/main/ds_runtime.c

@@ -0,0 +1,458 @@
+/**
+ * DreamStack Panel IR Runtime — Implementation
+ *
+ * Parses Panel IR JSON (using cJSON) and creates LVGL 9 widgets.
+ * This is the C port of the browser-based panel previewer logic.
+ *
+ * Key features:
+ *   - Signal table with text template expansion ({0} → value)
+ *   - Reactive updates: signal change → refresh bound labels
+ *   - Event dispatch: button click → action opcode → ESP-NOW
+ *   - Timer execution from IR timers[] array
+ */
+
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include "esp_log.h"
+#include "cJSON.h"
+#include "lvgl.h"
+
+#include "ds_runtime.h"
+
+static const char *TAG = "ds-runtime";
+
+// ─── Signal Table ───
+static ds_signal_t s_signals[DS_MAX_SIGNALS];
+static uint16_t    s_signal_count = 0;
+
+// ─── Timer Table ───
+static ds_timer_t  s_timers[DS_MAX_TIMERS];
+static uint8_t     s_timer_count = 0;
+
+// ─── Text Binding Table ───
+// Maps LVGL label objects to their IR text templates
+typedef struct {
+    lv_obj_t   *label;       // LVGL label widget
+    char        template[128]; // Text template with {N} placeholders
+    bool        used;
+} ds_binding_t;
+
+static ds_binding_t s_bindings[DS_MAX_BINDINGS];
+static uint16_t     s_binding_count = 0;
+
+// ─── Parent and Callback ───
+static lv_obj_t      *s_parent = NULL;
+static lv_obj_t      *s_root = NULL;
+static ds_action_cb_t s_action_cb = NULL;
+
+// ─── Forward Declarations ───
+static lv_obj_t *build_node(cJSON *node, lv_obj_t *parent);
+static void expand_template(const char *tpl, char *out, size_t out_len);
+static void execute_action(cJSON *action);
+static void refresh_bindings(void);
+
+// ─── Action opcodes (match IR spec) ───
+#define OP_INC     1
+#define OP_DEC     2
+#define OP_ADD     3
+#define OP_SUB     4
+#define OP_SET     5
+#define OP_TOGGLE  6
+
+static uint8_t parse_op(const char *op_str) {
+    if (strcmp(op_str, "inc") == 0) return OP_INC;
+    if (strcmp(op_str, "dec") == 0) return OP_DEC;
+    if (strcmp(op_str, "add") == 0) return OP_ADD;
+    if (strcmp(op_str, "sub") == 0) return OP_SUB;
+    if (strcmp(op_str, "set") == 0) return OP_SET;
+    if (strcmp(op_str, "toggle") == 0) return OP_TOGGLE;
+    return 0;
+}
+
+// ─── Timer Callback ───
+static void timer_cb(lv_timer_t *timer) {
+    ds_timer_t *t = (ds_timer_t *)lv_timer_get_user_data(timer);
+    if (!t) return;
+
+    int32_t val = s_signals[t->action_sig].i;
+    switch (t->action_op) {
+        case OP_INC: val++; break;
+        case OP_DEC: val--; break;
+        case OP_ADD: val += t->action_val; break;
+        case OP_SUB: val -= t->action_val; break;
+        case OP_SET: val = t->action_val; break;
+        case OP_TOGGLE: val = val ? 0 : 1; break;
+    }
+    ds_signal_update(t->action_sig, val);
+}
+
+// ─── Button Event Handler ───
+typedef struct {
+    cJSON *action;   // JSON action object (kept alive while UI exists)
+    uint8_t node_id;
+} btn_user_data_t;
+
+static void btn_click_cb(lv_event_t *e) {
+    btn_user_data_t *ud = (btn_user_data_t *)lv_event_get_user_data(e);
+    if (ud && ud->action) {
+        execute_action(ud->action);
+        if (s_action_cb) {
+            s_action_cb(ud->node_id, 0); // notify ESP-NOW
+        }
+    }
+}
+
+// ─── Build Helpers ───
+
+static lv_obj_t *build_container(cJSON *node, lv_obj_t *parent, bool is_row) {
+    lv_obj_t *cont = lv_obj_create(parent);
+    lv_obj_set_size(cont, LV_PCT(100), LV_SIZE_CONTENT);
+    lv_obj_set_flex_flow(cont, is_row ? LV_FLEX_FLOW_ROW : LV_FLEX_FLOW_COLUMN);
+    lv_obj_set_style_bg_opa(cont, LV_OPA_TRANSP, 0);
+    lv_obj_set_style_border_width(cont, 0, 0);
+    lv_obj_set_style_pad_all(cont, 4, 0);
+
+    cJSON *gap = cJSON_GetObjectItem(node, "gap");
+    if (gap) {
+        lv_obj_set_style_pad_gap(cont, gap->valueint, 0);
+    }
+
+    cJSON *children = cJSON_GetObjectItem(node, "c");
+    if (children && cJSON_IsArray(children)) {
+        cJSON *child;
+        cJSON_ArrayForEach(child, children) {
+            build_node(child, cont);
+        }
+    }
+    return cont;
+}
+
+static lv_obj_t *build_label(cJSON *node, lv_obj_t *parent) {
+    lv_obj_t *lbl = lv_label_create(parent);
+    cJSON *text = cJSON_GetObjectItem(node, "text");
+    if (text && text->valuestring) {
+        char expanded[256];
+        expand_template(text->valuestring, expanded, sizeof(expanded));
+        lv_label_set_text(lbl, expanded);
+
+        // Register binding if template contains {N}
+        if (strchr(text->valuestring, '{') && s_binding_count < DS_MAX_BINDINGS) {
+            ds_binding_t *b = &s_bindings[s_binding_count++];
+            b->label = lbl;
+            strncpy(b->template, text->valuestring, sizeof(b->template) - 1);
+            b->used = true;
+        }
+    }
+
+    cJSON *size = cJSON_GetObjectItem(node, "size");
+    if (size) {
+        lv_obj_set_style_text_font(lbl,
+            size->valueint >= 24 ? &lv_font_montserrat_24 :
+            size->valueint >= 18 ? &lv_font_montserrat_18 :
+            size->valueint >= 14 ? &lv_font_montserrat_14 :
+            &lv_font_montserrat_12, 0);
+    }
+
+    return lbl;
+}
+
+static lv_obj_t *build_button(cJSON *node, lv_obj_t *parent) {
+    lv_obj_t *btn = lv_btn_create(parent);
+    lv_obj_t *lbl = lv_label_create(btn);
+
+    cJSON *text = cJSON_GetObjectItem(node, "text");
+    if (text && text->valuestring) {
+        char expanded[256];
+        expand_template(text->valuestring, expanded, sizeof(expanded));
+        lv_label_set_text(lbl, expanded);
+
+        // Register binding for button text too
+        if (strchr(text->valuestring, '{') && s_binding_count < DS_MAX_BINDINGS) {
+            ds_binding_t *b = &s_bindings[s_binding_count++];
+            b->label = lbl;
+            strncpy(b->template, text->valuestring, sizeof(b->template) - 1);
+            b->used = true;
+        }
+    }
+
+    cJSON *on = cJSON_GetObjectItem(node, "on");
+    if (on) {
+        cJSON *click = cJSON_GetObjectItem(on, "click");
+        if (click) {
+            btn_user_data_t *ud = malloc(sizeof(btn_user_data_t));
+            ud->action = click;  // keep reference (IR JSON stays in memory)
+            cJSON *id_obj = cJSON_GetObjectItem(node, "id");
+            ud->node_id = id_obj ? id_obj->valueint : 0;
+            lv_obj_add_event_cb(btn, btn_click_cb, LV_EVENT_CLICKED, ud);
+        }
+    }
+
+    return btn;
+}
+
+static lv_obj_t *build_slider(cJSON *node, lv_obj_t *parent) {
+    lv_obj_t *slider = lv_slider_create(parent);
+    lv_obj_set_width(slider, LV_PCT(80));
+
+    cJSON *min = cJSON_GetObjectItem(node, "min");
+    cJSON *max = cJSON_GetObjectItem(node, "max");
+    if (min) lv_slider_set_range(slider, min->valueint, max ? max->valueint : 100);
+
+    cJSON *bind = cJSON_GetObjectItem(node, "bind");
+    if (bind) {
+        int sid = bind->valueint;
+        lv_slider_set_value(slider, s_signals[sid].i, LV_ANIM_OFF);
+        // TODO: add slider change event → ds_signal_update
+    }
+
+    return slider;
+}
+
+static lv_obj_t *build_panel(cJSON *node, lv_obj_t *parent) {
+    lv_obj_t *pnl = lv_obj_create(parent);
+    lv_obj_set_size(pnl, LV_PCT(100), LV_SIZE_CONTENT);
+    lv_obj_set_flex_flow(pnl, LV_FLEX_FLOW_COLUMN);
+    lv_obj_set_style_pad_all(pnl, 12, 0);
+    lv_obj_set_style_radius(pnl, 8, 0);
+
+    cJSON *title = cJSON_GetObjectItem(node, "text");
+    if (title && title->valuestring) {
+        lv_obj_t *t = lv_label_create(pnl);
+        lv_label_set_text(t, title->valuestring);
+        lv_obj_set_style_text_font(t, &lv_font_montserrat_14, 0);
+    }
+
+    cJSON *children = cJSON_GetObjectItem(node, "c");
+    if (children && cJSON_IsArray(children)) {
+        cJSON *child;
+        cJSON_ArrayForEach(child, children) {
+            build_node(child, pnl);
+        }
+    }
+
+    return pnl;
+}
+
+// ─── Node Dispatcher ───
+static lv_obj_t *build_node(cJSON *node, lv_obj_t *parent) {
+    if (!node) return NULL;
+
+    cJSON *type = cJSON_GetObjectItem(node, "t");
+    if (!type || !type->valuestring) return NULL;
+
+    const char *t = type->valuestring;
+
+    if (strcmp(t, "col") == 0) return build_container(node, parent, false);
+    if (strcmp(t, "row") == 0) return build_container(node, parent, true);
+    if (strcmp(t, "lbl") == 0) return build_label(node, parent);
+    if (strcmp(t, "btn") == 0) return build_button(node, parent);
+    if (strcmp(t, "sld") == 0) return build_slider(node, parent);
+    if (strcmp(t, "pnl") == 0) return build_panel(node, parent);
+    // stk, inp, sw, bar, img — add as needed
+
+    ESP_LOGW(TAG, "Unknown node type: %s", t);
+    return NULL;
+}
+
+// ─── Template Expansion ───
+// Replace {N} with signal values: "{2}: {0}°F" → "Kitchen: 72°F"
+static void expand_template(const char *tpl, char *out, size_t out_len) {
+    size_t pos = 0;
+    while (*tpl && pos < out_len - 1) {
+        if (*tpl == '{') {
+            tpl++;
+            int sig_id = 0;
+            while (*tpl >= '0' && *tpl <= '9') {
+                sig_id = sig_id * 10 + (*tpl - '0');
+                tpl++;
+            }
+            if (*tpl == '}') tpl++;
+
+            if (sig_id < DS_MAX_SIGNALS && s_signals[sig_id].used) {
+                int written = snprintf(out + pos, out_len - pos, "%d",
+                                       (int)s_signals[sig_id].i);
+                if (written > 0) pos += written;
+            }
+        } else {
+            out[pos++] = *tpl++;
+        }
+    }
+    out[pos] = '\0';
+}
+
+// ─── Action Executor ───
+static void execute_action(cJSON *action) {
+    if (!action) return;
+
+    // Handle arrays of actions
+    if (cJSON_IsArray(action)) {
+        cJSON *item;
+        cJSON_ArrayForEach(item, action) {
+            execute_action(item);
+        }
+        return;
+    }
+
+    cJSON *op_json = cJSON_GetObjectItem(action, "op");
+    cJSON *s_json = cJSON_GetObjectItem(action, "s");
+    if (!op_json || !s_json) return;
+
+    uint8_t op = parse_op(op_json->valuestring);
+    uint16_t sid = s_json->valueint;
+    if (sid >= DS_MAX_SIGNALS) return;
+
+    int32_t val = s_signals[sid].i;
+    cJSON *v_json = cJSON_GetObjectItem(action, "v");
+    int32_t v = v_json ? v_json->valueint : 0;
+
+    switch (op) {
+        case OP_INC: val++; break;
+        case OP_DEC: val--; break;
+        case OP_ADD: val += v; break;
+        case OP_SUB: val -= v; break;
+        case OP_SET: val = v; break;
+        case OP_TOGGLE: val = val ? 0 : 1; break;
+    }
+
+    ds_signal_update(sid, val);
+}
+
+// ─── Refresh Bindings ───
+// Called after any signal change to update bound labels
+static void refresh_bindings(void) {
+    for (int i = 0; i < s_binding_count; i++) {
+        if (!s_bindings[i].used) continue;
+        char expanded[256];
+        expand_template(s_bindings[i].template, expanded, sizeof(expanded));
+        lv_label_set_text(s_bindings[i].label, expanded);
+    }
+}
+
+// ─── Public API ───
+
+esp_err_t ds_runtime_init(void *parent, ds_action_cb_t action_cb) {
+    s_parent = (lv_obj_t *)parent;
+    s_action_cb = action_cb;
+    s_root = NULL;
+    s_signal_count = 0;
+    s_binding_count = 0;
+    s_timer_count = 0;
+    memset(s_signals, 0, sizeof(s_signals));
+    memset(s_bindings, 0, sizeof(s_bindings));
+    memset(s_timers, 0, sizeof(s_timers));
+
+    ESP_LOGI(TAG, "Runtime initialized");
+    return ESP_OK;
+}
+
+esp_err_t ds_ui_build(const char *ir_json, size_t length) {
+    // Destroy previous UI
+    ds_ui_destroy();
+
+    cJSON *ir = cJSON_ParseWithLength(ir_json, length);
+    if (!ir) {
+        ESP_LOGE(TAG, "Failed to parse IR JSON");
+        return ESP_ERR_INVALID_ARG;
+    }
+
+    // Load signals
+    cJSON *signals = cJSON_GetObjectItem(ir, "signals");
+    if (signals && cJSON_IsArray(signals)) {
+        cJSON *sig;
+        cJSON_ArrayForEach(sig, signals) {
+            cJSON *id = cJSON_GetObjectItem(sig, "id");
+            cJSON *v = cJSON_GetObjectItem(sig, "v");
+            if (id && id->valueint < DS_MAX_SIGNALS) {
+                int sid = id->valueint;
+                s_signals[sid].i = v ? v->valueint : 0;
+                s_signals[sid].type = DS_SIG_INT;
+                s_signals[sid].used = true;
+                s_signal_count++;
+            }
+        }
+    }
+
+    // Build UI tree
+    cJSON *root = cJSON_GetObjectItem(ir, "root");
+    if (root) {
+        s_root = build_node(root, s_parent);
+    }
+
+    // Load timers
+    cJSON *timers = cJSON_GetObjectItem(ir, "timers");
+    if (timers && cJSON_IsArray(timers)) {
+        cJSON *t;
+        cJSON_ArrayForEach(t, timers) {
+            if (s_timer_count >= DS_MAX_TIMERS) break;
+            cJSON *ms = cJSON_GetObjectItem(t, "ms");
+            cJSON *action = cJSON_GetObjectItem(t, "action");
+            if (ms && action) {
+                ds_timer_t *timer = &s_timers[s_timer_count];
+                timer->ms = ms->valueint;
+
+                cJSON *op = cJSON_GetObjectItem(action, "op");
+                cJSON *s = cJSON_GetObjectItem(action, "s");
+                cJSON *v = cJSON_GetObjectItem(action, "v");
+                timer->action_op = op ? parse_op(op->valuestring) : 0;
+                timer->action_sig = s ? s->valueint : 0;
+                timer->action_val = v ? v->valueint : 0;
+
+                timer->timer = lv_timer_create(timer_cb, timer->ms, timer);
+                s_timer_count++;
+                ESP_LOGI(TAG, "Timer: every %dms → op %d on s%d",
+                         (int)timer->ms, timer->action_op, timer->action_sig);
+            }
+        }
+    }
+
+    ESP_LOGI(TAG, "UI built: %d signals, %d bindings, %d timers",
+             s_signal_count, s_binding_count, s_timer_count);
+
+    // Keep IR JSON alive for button action references
+    // (cJSON_Delete would invalidate action pointers)
+    // TODO: deep-copy actions to avoid this leak
+
+    return ESP_OK;
+}
+
+void ds_ui_destroy(void) {
+    // Stop timers
+    for (int i = 0; i < s_timer_count; i++) {
+        if (s_timers[i].timer) {
+            lv_timer_delete((lv_timer_t *)s_timers[i].timer);
+            s_timers[i].timer = NULL;
+        }
+    }
+    s_timer_count = 0;
+
+    // Clear bindings
+    s_binding_count = 0;
+    memset(s_bindings, 0, sizeof(s_bindings));
+
+    // Destroy LVGL tree
+    if (s_root) {
+        lv_obj_del(s_root);
+        s_root = NULL;
+    }
+
+    ESP_LOGI(TAG, "UI destroyed");
+}
+
+void ds_signal_update(uint16_t signal_id, int32_t value) {
+    if (signal_id >= DS_MAX_SIGNALS) return;
+    s_signals[signal_id].i = value;
+    s_signals[signal_id].used = true;
+
+    // Refresh all bound labels
+    refresh_bindings();
+}
+
+uint16_t ds_signal_count(void) {
+    return s_signal_count;
+}
+
+int32_t ds_signal_get(uint16_t signal_id) {
+    if (signal_id >= DS_MAX_SIGNALS) return 0;
+    return s_signals[signal_id].i;
+}

devices/waveshare-p4-panel/main/ds_runtime.h

@@ -0,0 +1,90 @@
+/**
+ * DreamStack Panel IR Runtime — LVGL Widget Builder
+ *
+ * Parses Panel IR JSON and creates LVGL widgets.
+ * Handles signal binding, text template expansion,
+ * event dispatch, and timer execution.
+ *
+ * This is the C equivalent of the browser-based panel previewer.
+ */
+
+#pragma once
+#include <stdint.h>
+#include <stdbool.h>
+#include "esp_err.h"
+
+// ─── Limits ───
+#define DS_MAX_SIGNALS   64
+#define DS_MAX_NODES     128
+#define DS_MAX_TIMERS    8
+#define DS_MAX_BINDINGS  64
+
+// ─── Signal types ───
+typedef enum {
+    DS_SIG_INT = 0,
+    DS_SIG_BOOL,
+    DS_SIG_STRING,
+} ds_sig_type_t;
+
+// ─── Signal value ───
+typedef struct {
+    int32_t       i;        // integer value (also used for bool: 0/1)
+    char          s[32];    // string value (short strings only)
+    ds_sig_type_t type;
+    bool          used;
+} ds_signal_t;
+
+// ─── Timer entry ───
+typedef struct {
+    uint32_t    ms;         // interval in milliseconds
+    uint8_t     action_op;  // action opcode
+    uint16_t    action_sig; // target signal
+    int32_t     action_val; // value for set/add/sub
+    void       *timer;      // LVGL timer handle (lv_timer_t *)
+} ds_timer_t;
+
+// ─── Action callback (for forwarding to ESP-NOW) ───
+typedef void (*ds_action_cb_t)(uint8_t node_id, uint8_t action_type);
+
+/**
+ * Initialize the Panel IR runtime.
+ * Must be called after LVGL is initialized.
+ *
+ * @param parent     LVGL parent object (usually lv_scr_act())
+ * @param action_cb  Callback for widget actions (forwarded to ESP-NOW)
+ */
+esp_err_t ds_runtime_init(void *parent, ds_action_cb_t action_cb);
+
+/**
+ * Build the UI from Panel IR JSON.
+ * Parses the JSON, creates LVGL widgets, binds signals.
+ * Destroys any previously built UI first.
+ *
+ * @param ir_json  Panel IR JSON string
+ * @param length   Length of the JSON string
+ */
+esp_err_t ds_ui_build(const char *ir_json, size_t length);
+
+/**
+ * Destroy the current UI tree.
+ * Removes all LVGL widgets and clears signal bindings.
+ */
+void ds_ui_destroy(void);
+
+/**
+ * Update a signal value and refresh bound widgets.
+ *
+ * @param signal_id  Signal ID (0-based)
+ * @param value      New integer value
+ */
+void ds_signal_update(uint16_t signal_id, int32_t value);
+
+/**
+ * Get current signal count.
+ */
+uint16_t ds_signal_count(void);
+
+/**
+ * Get signal value by ID.
+ */
+int32_t ds_signal_get(uint16_t signal_id);

devices/waveshare-p4-panel/main/main.c

@@ -1,15 +1,12 @@
 /**
  * DreamStack Thin Client — Waveshare ESP32-P4 10.1" Panel
  *
- * Firmware that turns the panel into a dumb pixel display
+ * Dual transport firmware:
- * with touch input. All rendering happens on the source device.
+ *   1. ESP-NOW + Panel IR (primary) — sub-1ms signal delivery, LVGL native rendering
+ *   2. WebSocket + pixel streaming (fallback) — for non-DreamStack content
  *
- * Flow: WiFi → WebSocket → receive delta frames → blit to display
+ * Build with -DDS_USE_ESPNOW=1 for ESP-NOW mode (default)
- *       Touch → encode event → send over WebSocket
+ * Build with -DDS_USE_ESPNOW=0 for WebSocket-only pixel mode
- *
- * Dependencies (via ESP Component Registry):
- *   - waveshare/esp_lcd_jd9365_10_1  (10.1" MIPI DSI display driver)
- *   - espressif/esp_websocket_client (WebSocket client)
  */
 
 #include <stdio.h>
@@ -21,26 +18,39 @@
 #include "esp_event.h"
 #include "nvs_flash.h"
 #include "esp_lcd_panel_ops.h"
-#include "esp_websocket_client.h"
 
 #include "ds_codec.h"
 #include "ds_protocol.h"
 
+// ─── Transport selection ───
+#ifndef DS_USE_ESPNOW
+#define DS_USE_ESPNOW  1
+#endif
+
+#if DS_USE_ESPNOW
+#include "ds_espnow.h"
+#include "ds_runtime.h"
+#endif
+
 static const char *TAG = "ds-panel";
 
-// ─── Configuration (set via menuconfig or hardcode for POC) ───
+// ─── Configuration ───
 #define PANEL_WIDTH    800
 #define PANEL_HEIGHT   1280
 #define PIXEL_BYTES    2        // RGB565
-#define FB_SIZE        (PANEL_WIDTH * PANEL_HEIGHT * PIXEL_BYTES)  // ~2MB
+#define FB_SIZE        (PANEL_WIDTH * PANEL_HEIGHT * PIXEL_BYTES)
 
 #define WIFI_SSID      CONFIG_WIFI_SSID
 #define WIFI_PASS      CONFIG_WIFI_PASS
-#define RELAY_URL      CONFIG_RELAY_URL   // e.g. "ws://192.168.1.100:9100/stream/home"
 
-// ─── Framebuffers (in PSRAM) ───
+#if !DS_USE_ESPNOW
-static uint8_t *framebuffer;    // Current display state
+#define RELAY_URL      CONFIG_RELAY_URL
-static uint8_t *scratch_buf;    // Temp buffer for delta decode
+#include "esp_websocket_client.h"
+#endif
+
+// ─── Framebuffers (in PSRAM, for pixel mode) ───
+static uint8_t *framebuffer;
+static uint8_t *scratch_buf;
 
 // ─── Display handle ───
 static esp_lcd_panel_handle_t panel_handle = NULL;
@@ -48,7 +58,63 @@ static esp_lcd_panel_handle_t panel_handle = NULL;
 // ─── Touch state ───
 static uint16_t input_seq = 0;
 
-// ─── WebSocket event handler ───
+#if DS_USE_ESPNOW
+// ═══════════════════════════════════════════════════════
+// ESP-NOW + Panel IR Mode
+// ═══════════════════════════════════════════════════════
+
+static void on_signal(uint16_t signal_id, int32_t value) {
+    // Feed signal updates to the Panel IR runtime
+    ds_signal_update(signal_id, value);
+    ESP_LOGD(TAG, "Signal %d = %d", signal_id, (int)value);
+}
+
+static void on_ir_push(const char *ir_json, size_t length) {
+    // Build LVGL UI from Panel IR JSON
+    ESP_LOGI(TAG, "IR push received (%zu bytes), building UI...", length);
+    esp_err_t ret = ds_ui_build(ir_json, length);
+    if (ret == ESP_OK) {
+        ESP_LOGI(TAG, "UI built: %d signals", ds_signal_count());
+    } else {
+        ESP_LOGE(TAG, "Failed to build UI from IR");
+    }
+}
+
+static void on_action(uint8_t node_id, uint8_t action_type) {
+    // Forward widget actions to hub via ESP-NOW
+    ds_espnow_send_action(node_id, action_type);
+}
+
+static void espnow_init_and_run(void) {
+    // Initialize Panel IR runtime (LVGL must be ready)
+    // TODO: replace NULL with lv_scr_act() once LVGL is initialized
+    ds_runtime_init(NULL, on_action);
+
+    // Initialize ESP-NOW transport
+    ds_espnow_config_t config = {
+        .hub_mac = {0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF},  // broadcast
+        .channel = DS_ESPNOW_CHANNEL,
+        .on_signal = on_signal,
+        .on_ir_push = on_ir_push,
+    };
+    esp_err_t ret = ds_espnow_init(&config);
+    if (ret != ESP_OK) {
+        ESP_LOGE(TAG, "ESP-NOW init failed");
+        return;
+    }
+
+    // Send periodic pings so hub discovers us
+    while (1) {
+        ds_espnow_send_ping();
+        vTaskDelay(pdMS_TO_TICKS(5000));
+    }
+}
+
+#else
+// ═══════════════════════════════════════════════════════
+// WebSocket Pixel Streaming Mode (Legacy)
+// ═══════════════════════════════════════════════════════
+
 static void ws_event_handler(void *arg, esp_event_base_t base,
                              int32_t event_id, void *event_data) {
     esp_websocket_event_data_t *data = (esp_websocket_event_data_t *)event_data;
@@ -69,7 +135,6 @@ static void ws_event_handler(void *arg, esp_event_base_t base,
 
         switch (hdr.frame_type) {
         case DS_FRAME_PIXELS:
-            // Full keyframe — copy directly to framebuffer
             if (payload_len == FB_SIZE) {
                 memcpy(framebuffer, payload, FB_SIZE);
                 esp_lcd_panel_draw_bitmap(panel_handle,
@@ -79,7 +144,6 @@ static void ws_event_handler(void *arg, esp_event_base_t base,
             break;
 
         case DS_FRAME_DELTA:
-            // Delta frame — RLE decode + XOR apply
             if (ds_apply_delta_rle(framebuffer, FB_SIZE,
                                    payload, payload_len, scratch_buf) == 0) {
                 esp_lcd_panel_draw_bitmap(panel_handle,
@@ -90,7 +154,6 @@ static void ws_event_handler(void *arg, esp_event_base_t base,
             break;
 
         case DS_FRAME_PING:
-            // Respond with pong (same message back)
             break;
 
         case DS_FRAME_END:
@@ -109,7 +172,6 @@ static void ws_event_handler(void *arg, esp_event_base_t base,
     }
 }
 
-// ─── Send touch event over WebSocket ───
 static void send_touch_event(esp_websocket_client_handle_t ws,
                              uint8_t id, uint16_t x, uint16_t y, uint8_t phase) {
     uint8_t buf[DS_HEADER_SIZE + sizeof(ds_touch_event_t)];
@@ -120,52 +182,27 @@ static void send_touch_event(esp_websocket_client_handle_t ws,
     esp_websocket_client_send_bin(ws, (const char *)buf, len, portMAX_DELAY);
 }
 
-// ─── Touch polling task ───
+#endif // DS_USE_ESPNOW
-//
-// TODO: Replace with actual GT9271 I2C touch driver.
-// The Waveshare BSP should provide touch reading functions.
-// This is a placeholder showing the integration pattern.
-//
-static void touch_task(void *arg) {
-    esp_websocket_client_handle_t ws = (esp_websocket_client_handle_t)arg;
 
+// ─── Touch polling task ───
+static void touch_task(void *arg) {
     while (1) {
         // TODO: Read from GT9271 touch controller via I2C
-        // Example (pseudocode):
-        //
         // gt9271_touch_data_t td;
         // if (gt9271_read(&td) == ESP_OK && td.num_points > 0) {
-        //     for (int i = 0; i < td.num_points; i++) {
+        //     #if DS_USE_ESPNOW
-        //         send_touch_event(ws, td.points[i].id,
+        //         ds_espnow_send_touch(0, 0, td.points[0].x, td.points[0].y);
-        //                         td.points[i].x, td.points[i].y,
+        //     #else
-        //                         td.points[i].phase);
+        //         send_touch_event(ws, ...);
-        //     }
+        //     #endif
         // }
-
         vTaskDelay(pdMS_TO_TICKS(10));  // 100Hz touch polling
     }
 }
 
 // ─── Display initialization ───
-//
-// TODO: Initialize MIPI DSI display using Waveshare component.
-// Add `waveshare/esp_lcd_jd9365_10_1` to idf_component.yml
-//
 static esp_err_t display_init(void) {
-    // TODO: Configure MIPI DSI bus and JD9365 panel driver
+    // TODO: Initialize MIPI DSI display using Waveshare component
-    // Example (pseudocode):
-    //
-    // esp_lcd_dsi_bus_config_t bus_cfg = { ... };
-    // esp_lcd_new_dsi_bus(&bus_cfg, &dsi_bus);
-    //
-    // esp_lcd_panel_dev_config_t panel_cfg = {
-    //     .reset_gpio_num = ...,
-    //     .rgb_ele_order = LCD_RGB_ELEMENT_ORDER_RGB,
-    //     .bits_per_pixel = 16,  // RGB565
-    // };
-    // esp_lcd_new_panel_jd9365_10_1(dsi_bus, &panel_cfg, &panel_handle);
-    // esp_lcd_panel_init(panel_handle);
-
     ESP_LOGI(TAG, "Display initialized (%dx%d RGB565)", PANEL_WIDTH, PANEL_HEIGHT);
     return ESP_OK;
 }
@@ -188,48 +225,57 @@ static void wifi_init(void) {
     esp_wifi_set_mode(WIFI_MODE_STA);
     esp_wifi_set_config(WIFI_IF_STA, &wifi_cfg);
     esp_wifi_start();
-    esp_wifi_connect();
 
+#if DS_USE_ESPNOW
+    // For ESP-NOW: don't need to connect to AP, just start WiFi
+    ESP_LOGI(TAG, "WiFi started (ESP-NOW mode, no AP connection needed)");
+#else
+    esp_wifi_connect();
     ESP_LOGI(TAG, "WiFi connecting to %s...", WIFI_SSID);
+#endif
 }
 
 // ─── Main ───
 void app_main(void) {
-    ESP_LOGI(TAG, "DreamStack Thin Client v0.1");
+#if DS_USE_ESPNOW
-    ESP_LOGI(TAG, "Panel: %dx%d @ %d bpp = %d bytes",
+    ESP_LOGI(TAG, "DreamStack Panel v0.2 (ESP-NOW + Panel IR)");
+#else
+    ESP_LOGI(TAG, "DreamStack Panel v0.2 (WebSocket + Pixel)");
+#endif
+    ESP_LOGI(TAG, "Display: %dx%d @ %d bpp = %d bytes",
              PANEL_WIDTH, PANEL_HEIGHT, PIXEL_BYTES * 8, FB_SIZE);
 
-    // Initialize NVS (required for WiFi)
     nvs_flash_init();
 
-    // Allocate framebuffers in PSRAM
+    // Allocate framebuffers in PSRAM (needed for pixel mode, optional for IR mode)
     framebuffer = heap_caps_calloc(1, FB_SIZE, MALLOC_CAP_SPIRAM);
     scratch_buf = heap_caps_calloc(1, FB_SIZE, MALLOC_CAP_SPIRAM);
     if (!framebuffer || !scratch_buf) {
         ESP_LOGE(TAG, "Failed to allocate framebuffers in PSRAM (%d bytes each)", FB_SIZE);
         return;
     }
-    ESP_LOGI(TAG, "Framebuffers allocated in PSRAM (%d MB each)", FB_SIZE / (1024 * 1024));
 
-    // Initialize display
     display_init();
-
-    // Initialize WiFi
     wifi_init();
-    vTaskDelay(pdMS_TO_TICKS(3000));  // Wait for WiFi connection
+    vTaskDelay(pdMS_TO_TICKS(2000));
 
-    // Connect WebSocket to relay
+#if DS_USE_ESPNOW
+    // ESP-NOW mode: init transport + runtime, wait for IR push
+    espnow_init_and_run();
+#else
+    // WebSocket mode: connect to relay, receive pixel frames
     esp_websocket_client_config_t ws_cfg = {
         .uri = RELAY_URL,
-        .buffer_size = 64 * 1024,  // 64KB receive buffer
+        .buffer_size = 64 * 1024,
     };
     esp_websocket_client_handle_t ws = esp_websocket_client_init(&ws_cfg);
     esp_websocket_register_events(ws, WEBSOCKET_EVENT_ANY, ws_event_handler, NULL);
     esp_websocket_client_start(ws);
     ESP_LOGI(TAG, "WebSocket connecting to %s...", RELAY_URL);
 
-    // Start touch polling task
     xTaskCreate(touch_task, "touch", 4096, ws, 5, NULL);
+#endif
 
-    ESP_LOGI(TAG, "Thin client running. Waiting for frames...");
+    ESP_LOGI(TAG, "Panel running. Waiting for frames...");
 }
+

docs/explorations.md

@@ -0,0 +1,449 @@
+# DreamStack Hardware Explorations
+
+> Research notes on form factors, display technologies, and touch input methods for DreamStack-powered surfaces.
+
+---
+
+## 1. USB Dongle (Chromecast-like)
+
+The DreamStack relay protocol + delta codec already does 90% of the work. A dongle receives the bitstream and outputs to HDMI.
+
+### Path A: ESP32-S3 HDMI Dongle (~$15 DIY)
+
+| Component | Part | Cost |
+|-----------|------|------|
+| SoC | ESP32-S3-WROOM-1 (N16R8) | ~$4 |
+| HDMI output | CH7035B or ADV7513 HDMI encoder IC | ~$3 |
+| USB-C power | Standard power-only connector | ~$0.50 |
+| PCB + passives | Custom PCB (JLCPCB) | ~$5 for 5 boards |
+| HDMI connector | Type-A male or mini-HDMI | ~$1 |
+
+- ESP32-S3 LCD parallel interface → HDMI encoder IC → HDMI out
+- WiFi connects to DreamStack relay, receives delta-compressed frames
+- Resolution limit: ~480×320 smooth, 800×600 at lower FPS
+- Input via BLE HID remote or HDMI CEC (pin 13)
+
+### Path B: Linux Stick / Allwinner (~$25-40)
+
+MangoPi MQ-Pro / Radxa Zero form factor:
+
+| Component | Part | Cost |
+|-----------|------|------|
+| SoC | Allwinner H616/H618 (HDMI built-in) | ~$15 module |
+| RAM | 512MB DDR3 onboard | included |
+| WiFi | RTL8723CS | ~$3 |
+| Storage | 8GB eMMC or SD | ~$3 |
+
+- Runs minimal Linux (Buildroot), headless browser or C receiver writing to `/dev/fb0`
+- Native HDMI — no encoder IC needed
+- Full DreamStack JS runtime in headless Chromium/WPE-WebKit
+- CEC for remote control
+
+### Path C: Pi Zero 2 W (~$15, recommended MVP)
+
+Best for proving the concept immediately — $15, mini-HDMI out, WiFi, runs DreamStack natively.
+
+```
+Laptop                    WiFi/LAN           Pi Zero 2 W (in 3D-printed HDMI case)
+──────                    ─────────          ─────────────────────────────────────
+dreamstack dev app.ds                        headless browser / ds_runtime
+  → relay-bridge ──────── WebSocket ───────→   → HDMI out to TV
+                          ←── CEC/BLE ←────  remote control
+```
+
+### Off-the-shelf stick computers
+
+| Device | Price | HDMI | WiFi | Notes |
+|--------|-------|------|------|-------|
+| Raspberry Pi Zero 2 W | $15 | Mini-HDMI ✅ | ✅ | Best form factor |
+| MangoPi MQ-Pro (RISC-V) | $20 | HDMI ✅ | ✅ | Stick form factor |
+| Radxa Zero | $25 | Micro-HDMI ✅ | ✅ | Amlogic S905Y2 |
+| T-Dongle S3 (LilyGO) | $12 | No (LCD only) | ✅ | ESP32-S3, tiny LCD |
+
+---
+
+## 2. Projected Touch Wall
+
+### Architecture
+
+```
+SOURCE (laptop/Pi)              RELAY (:9100)              WALL
+───────────────                 ─────────────              ────
+DreamStack app                  WebSocket hub              UST Projector
+800×1280 canvas                                            + touch overlay
+
+pixels → XOR delta → RLE ────→ relay ─────────────────→   decode → project
+                                ←── touch {x,y,phase} ←── touch sensor
+```
+
+### Ultra-Short-Throw Projectors
+
+| Product | Price (new) | Price (used) | Notes |
+|---------|-------------|-------------|-------|
+| Xiaomi Laser Cinema 2 | ~$1,200 | ~$400 | Good value |
+| BenQ V7050i | ~$2,500 | ~$800 | 4K HDR |
+| JMGO U2 | ~$1,000 | ~$300 | Budget friendly |
+| Epson LS500 | ~$2,000 | ~$600 | Bright |
+
+Wall prep: screen paint (Silver Ticket / Rust-Oleum, ~$30).
+
+---
+
+## 3. Touch Input Technologies
+
+Ranked from fastest to slowest latency:
+
+### 3a. Piezoelectric Sensors (<1ms, ~$7)
+
+Stick 3-4 piezo discs on the **back** of the wall. Finger taps create vibrations; time-difference-of-arrival (TDOA) triangulates X,Y.
+
+| Part | Cost |
+|------|------|
+| 4× piezo disc (35mm) | ~$2 |
+| ESP32-S3 (built-in ADC, 40kHz+ sampling) | ~$5 |
+
+```
+Wall (drywall, glass, wood, whiteboard)
+┌───────────────────────────────────────┐
+│  P1 ●                       ● P2     │
+│               👆 TAP                 │
+│  P3 ●                       ● P4     │
+└───────────────────────────────────────┘
+       └────── ESP32 (TDOA → x,y) ─────┘
+```
+
+**Pros:** Near-instant, invisible, dirt cheap, works through paint
+**Cons:** Only detects **taps** (not drag/hover), needs hard surface
+
+---
+
+### 3b. Capacitive Wire/Paint Grid (1-3ms, ~$21 DIY)
+
+Grid of conductors (copper tape or conductive paint) behind the wall. Measures capacitance change when a finger approaches.
+
+| Part | Cost |
+|------|------|
+| Copper tape grid (30 channels) or graphite paint | ~$10 |
+| MPR121 capacitive controller ×3 | ~$6 |
+| ESP32 | ~$5 |
+
+**Supports:** Touch ✅ Drag ✅ Multi-touch ✅ Hover (~1-2cm) ✅
+**Resolution:** Depends on grid pitch — 3cm pitch ≈ 30×40 nodes over 100"
+
+#### How Mutual Capacitance Works
+
+Two layers of conductors (rows + columns) cross each other, separated by a thin insulator. Each intersection forms a capacitor. A finger near any intersection absorbs electric field, reducing measured capacitance.
+
+The controller scans one row at a time (AC drive), reads all columns simultaneously. Full scan of 30×40 grid: ~0.5-1ms. Continuous scanning gives automatic drag/swipe detection. Sub-pixel interpolation from adjacent node readings gives ~1mm accuracy from 5mm pitch.
+
+#### Recommended ICs
+
+| IC | Grid Size | Touch Points | Price |
+|----|-----------|-------------|-------|
+| MTCH6303 (Microchip) | 15×49 | 10 | ~$5 |
+| IQS7211A (Azoteq) | 15×22 | 5 | ~$3 |
+| GT911 (Goodix) | 26×14 | 5 | ~$2 |
+| FT5x06 (FocalTech) | 24×14 | 5 | ~$2 |
+
+---
+
+### 3c. FTIR — Frustrated Total Internal Reflection (3-8ms, ~$110-250)
+
+Acrylic sheet on wall with IR LEDs on edges (total internal reflection). Finger touch "frustrates" the reflection → bright spots detected by IR camera.
+
+| Part | Cost |
+|------|------|
+| 4mm acrylic sheet (100") | ~$80-150 |
+| IR LED strip (850nm) on edges | ~$10 |
+| IR camera (120fps, no IR filter) | ~$15 |
+| ESP32-S3 or Pi | ~$5-75 |
+
+**Pros:** Multi-touch, precise, pressure-sensitive (brighter blob = more pressure)
+**Cons:** Needs smooth flat surface (acrylic)
+
+---
+
+### 3d. IR Touch Frame (8-15ms, ~$250-500)
+
+Aluminum frame with IR LEDs + sensors on 4 edges. Finger breaks IR beams → X,Y.
+
+| Size | Price | Touch Points |
+|------|-------|-------------|
+| 65" | ~$250 | 6-10 pt |
+| 82" | ~$350 | 10-20 pt |
+| 100" | ~$500 | 10-20 pt |
+| 120"+ | ~$800+ | 20+ pt |
+
+Premium: Neonode zForce (~6-8ms, 200Hz). Budget: generic Chinese frames (~15-30ms, 100Hz).
+
+**Pros:** USB HID plug-and-play, works on any surface
+**Cons:** Physical border/bezel on wall
+
+---
+
+### 3e. Depth Camera (15-30ms, ~$80-450)
+
+| Camera | FPS | Latency | Range | Price |
+|--------|-----|---------|-------|-------|
+| **Intel RealSense D405** | 90fps | ~11ms | 7cm-50cm | ~$80 |
+| RealSense D435i | 90fps | ~11ms | 10cm-10m | ~$200 |
+| OAK-D SR (Short Range) | 60fps | ~12ms | 2cm-100cm | ~$150 |
+| OAK-D Pro | 30fps depth | ~15ms | 20cm-15m | ~$200 |
+| Stereolabs ZED Mini | 100fps | ~10ms | 10cm-12m | ~$300 |
+| Stereolabs ZED X Mini | 120fps | ~8ms | 10cm-15m | ~$450 |
+| Orbbec Gemini 2 | 60fps | ~16ms | 15cm-10m | ~$130 |
+
+**RealSense D405** is ideal for wall touch — 90fps hardware stereo depth, 7cm minimum distance, global shutter. No ML needed for touch detection: just threshold the depth map (`depth < 5mm → TOUCH`, `< 150mm → HOVER`).
+
+Layer MediaPipe on top (parallel) for gesture classification.
+
+---
+
+### 3f. Hybrid: Best of All Worlds
+
+| Input | Method | Latency |
+|-------|--------|---------|
+| Tap detection + pressure | Piezo (4 corners) | <1ms |
+| Touch + drag + hover | Capacitive grid | 1-3ms |
+| Hand gestures (air) | RealSense D405 | ~15ms |
+
+---
+
+## 4. Gesture / Hand Tracking
+
+### DIY Approaches (Ultraleap alternative)
+
+#### Stereo IR Camera + MediaPipe (~$30-50)
+
+Two OV2710 IR USB cameras (stereo pair, ~$15 each) + 850nm IR LED strip (~$5). MediaPipe Hands on Pi 5 or Jetson: 21 landmarks per hand, 30-120fps. Stereo triangulation gives Z. **Latency: ~20-30ms.**
+
+#### Single Depth Camera (~$80-150)
+
+Use RealSense D405 or OAK-D SR (see above). Hardware depth gives Z-distance from wall.
+
+#### ESP32-S3 + IR Matrix (~$20, lowest latency)
+
+IR LEDs flood the area in front of the wall. 2-3 IR cameras do blob detection at 120fps on ESP32-S3. Z estimated from blob size. No ML needed. **Latency: 5-10ms.**
+
+---
+
+## 5. Conductive Paint Recipes
+
+For capacitive grid electrodes painted directly on walls.
+
+### Graphite Paint (easiest, ~$5)
+
+| Ingredient | Amount | Source |
+|-----------|--------|--------|
+| Graphite powder (<45μm) | 3 tbsp | Art supply, Amazon (~$8/lb) |
+| PVA glue (white school glue) | 2 tbsp | Any store |
+| Water | 1 tbsp | Tap |
+
+~60% graphite, 30% glue, 10% water by volume. **Resistance: ~500-2000 Ω/sq.** Good enough for capacitive sensing.
+
+### Carbon Black + Acrylic (~$15)
+
+20-25% carbon black powder (conductive grade) in 75-80% acrylic medium. **Resistance: ~200-800 Ω/sq.** Better adhesion. Wear mask + gloves.
+
+### Nickel Paint (~$20)
+
+MG Chemicals 841, premade. **Resistance: ~5-50 Ω/sq.** Mid-range.
+
+### Silver Paint (~$30-50)
+
+Premade: Bare Conductive (~$25/50ml), MG Chemicals 842.
+DIY: 70-80% silver flake powder (<10μm), 15-20% acrylic medium, 5-10% butyl acetate.
+**Resistance: ~0.5-5 Ω/sq.** Near-wire conductivity.
+
+### For capacitive sensing: graphite is sufficient
+
+Capacitive touch doesn't need low resistance — just enough conductivity to couple with a finger. Paint lines with tape masking at 3-5cm spacing.
+
+---
+
+## 6. Pixel Paint — Paint-On Displays
+
+### Electroluminescent (EL) Paint Display
+
+Real and buildable. A stack of painted layers that glow when AC voltage is applied.
+
+```
+Layer stack (painted in order):
+
+  5. Clear topcoat
+  4. Transparent conductor (PEDOT:PSS)         ← rows
+  3. Phosphor layer (ZnS:Cu in acrylic)        ← glows
+  2. Dielectric (BaTiO₃ in acrylic)            ← insulator
+  1. Base conductor (silver/carbon paint)       ← columns
+  ─── Wall surface ───
+```
+
+Row/column intersection = one pixel. AC across a specific row+column → only that intersection glows (passive matrix).
+
+| Layer | Material | Cost/m² |
+|-------|----------|---------|
+| Base conductor (columns) | Silver paint, painted in strips | ~$50 |
+| Dielectric | Barium titanate (BaTiO₃) in acrylic | ~$30 |
+| Phosphor | ZnS:Cu powder in acrylic | ~$20 |
+| Top conductor (rows) | PEDOT:PSS | ~$40 |
+| Driver electronics | HV507 shift registers + ESP32 | ~$30 |
+| **Total** | | **~$170/m²** |
+
+#### Resolution at different pitches
+
+| Pixel Pitch | Pixels (100" wall) | Comparable To |
+|------------|---------------------|---------------|
+| 20mm | 110×65 = 7,150 | LED sign |
+| 10mm | 220×130 = 28,600 | Scoreboard |
+| 5mm | 440×260 = 114,400 | ~400×260 display ✅ |
+| 2mm | 1100×650 = 715,000 | Near SD |
+
+At 5mm pitch: 440×260 — enough for DreamStack UIs, dashboards, snake game.
+
+#### Color
+
+- ZnS:Cu → green (brightest)
+- ZnS:Cu,Mn → amber/orange
+- ZnS:Cu,Al → blue-green
+- Full RGB requires 3 sub-pixels per pixel (3× driver count)
+- Monochrome green is practical and looks great
+
+#### Built-in touch (free!)
+
+The row/column electrodes double as capacitive sensing electrodes via time-multiplexing:
+1. **Sense phase** (1ms): measure capacitance = touch position
+2. **Drive phase** (15ms): apply AC = illuminate pixels
+
+Same paint layers, no extra hardware.
+
+#### Driver IC
+
+HV507 — 64-channel high-voltage shift register. Drives 100V+ outputs from 3.3V SPI. Chain several for full display.
+
+### Other Display Paint Technologies (Future)
+
+| Technology | Status | Color | Speed |
+|-----------|--------|-------|-------|
+| Electrochromic (PEDOT:PSS, WO₃) | Real | Grayscale | 1-30s (too slow for video) |
+| Thermochromic + resistive grid | Hackable | Limited | 1-5s |
+| Perovskite spray-on LEDs | Lab only | Full color | ~ms |
+| QD-LED inkjet | Lab only | Full color | ~ms |
+
+Perovskite / QD-LED spray-on is the future (~2028-2030) but not available today.
+
+---
+
+## 7. Off-the-Shelf Solutions
+
+### Capacitive Touch Overlays (stick-on film)
+
+| Product | Max Size | Touch Points | Latency | Price |
+|---------|----------|-------------|---------|-------|
+| **Displax Skin Ultra** | 105" | 40 | ~6ms | ~$800-1500 |
+| Visual Planet TouchFoil | 100"+ | 40 | ~8ms | ~$600-1200 |
+| PQ Labs iTouch Plus | 150"+ | 32 | ~8ms | ~$400-900 |
+| AliExpress "PCAP touch foil" | 100"+ | 10 | ~10-15ms | ~$200-400 |
+
+Displax Skin Ultra: transparent polymer film with nano-wire grid, adhesive-backed, works through 6mm of material, USB HID, detects hover at ~2cm. Stick on wall, plug USB, done.
+
+### All-in-One Interactive Projectors
+
+| Product | Size | Touch | Latency | Price (new) |
+|---------|------|-------|---------|-------------|
+| **Epson BrightLink 770Fi** | 100" | 10pt + pen | ~10ms | ~$2,500 |
+| Epson BrightLink 735Fi | 100" | 10pt + pen | ~10ms | ~$2,000 |
+| BenQ LW890UST | 100" | 10pt | ~12ms | ~$1,800 |
+| Boxlight Mimio MiXX | 100" | 20pt | ~8ms | ~$2,200 |
+
+**Used education projectors** (schools constantly upgrade):
+
+| Used Option | Price |
+|-------------|-------|
+| Epson BrightLink 695Wi/696Ui | $300-600 |
+| BenQ MW855UST+ with PointWrite | $400-700 |
+| Promethean UST + ActivBoard | $300-500 |
+
+### Interactive Flat Panels (giant touchscreen monitors)
+
+| Product | Size | Price (new) | Price (used) |
+|---------|------|-------------|-------------|
+| **SMART Board MX** | 65-86" | $3,000-6,000 | $500-1,500 |
+| Promethean ActivPanel | 65-86" | $3,000-5,000 | $600-1,200 |
+| ViewSonic ViewBoard | 65-98" | $2,000-8,000 | $500-1,500 |
+| Samsung Flip | 55-85" | $2,000-4,000 | $800-2,000 |
+| Microsoft Surface Hub 2S | 50-85" | $5,000-12,000 | $1,500-3,000 |
+
+---
+
+## 8. Recommended Builds
+
+### Budget: $675
+
+| Component | Source | Price |
+|-----------|--------|-------|
+| Used SMART Board 65" | eBay | ~$600 |
+| Pi 5 | Official | ~$75 |
+
+Plug HDMI + USB, run DreamStack, done.
+
+### Mid-Range: $700
+
+| Component | Price |
+|-----------|-------|
+| UST projector (used) | ~$300 |
+| PCAP touch foil 100" (AliExpress) | ~$300 |
+| Pi 5 | ~$75 |
+| Screen paint | ~$30 |
+
+### Premium: $1,050
+
+| Component | Price |
+|-----------|-------|
+| UST projector (used) | ~$400 |
+| 100" IR touch frame | ~$350 |
+| RealSense D405 (gestures + hover) | ~$80 |
+| Pi 5 | ~$75 |
+| Piezo sensors (4 corners, tap confirm) | ~$7 |
+| Screen paint | ~$30 |
+
+Touch at 8-15ms + hover/gestures at 15ms + tap confirmation at <1ms.
+
+### DIY Maximum: ~$200 + wall paint
+
+| Component | Price |
+|-----------|-------|
+| Conductive graphite paint (capacitive grid) | ~$10 |
+| MPR121/MTCH6303 cap-touch IC | ~$5 |
+| ESP32-S3 | ~$5 |
+| UST projector (used) | ~$300 |
+
+Paint your own touch grid on the wall, 1-3ms latency, no frame needed.
+
+---
+
+## 9. DreamStack Integration
+
+All touch methods feed into the existing relay protocol:
+
+```
+Touch sensor (any method above)
+  → ESP32 or Pi reads touch events
+  → Encodes as DreamStack protocol:
+       0x01 Pointer move    (x, y)
+       0x02 Pointer down    (x, y, buttons)
+       0x03 Pointer up
+       0x10 KeyDown         (keyCode)
+       0x20 Hover           (x, y, z_distance)    ← new
+       0x21 Swipe           (direction, velocity)  ← new
+       0x22 Pinch/Grab      (state)                ← new
+  → WebSocket → DreamStack relay
+  → App receives as signal updates
+```
+
+DreamStack syntax for handling:
+
+```
+on hover(ev) -> opacity = lerp(0.5, 1.0, ev.z)
+on swipe(ev) -> navigate(if ev.dir == "left" then "/next" else "/prev")
+on grab(ev) -> scale = if ev.closed then 0.9 else 1.0
+```

engine/ds-screencast/capture.js

@@ -0,0 +1,259 @@
+#!/usr/bin/env node
+/**
+ * DreamStack Screencast — CDP Capture Agent
+ *
+ * Streams any web page to DreamStack panels via Chrome DevTools Protocol.
+ * Zero changes to the target app — just point at any URL.
+ *
+ * Usage:
+ *   node capture.js [url] [--headless] [--fps=N] [--quality=N]
+ *
+ * Examples:
+ *   node capture.js http://localhost:3000
+ *   node capture.js https://react.dev --headless --fps=30
+ */
+
+const CDP = require('chrome-remote-interface');
+const { WebSocketServer } = require('ws');
+const http = require('http');
+const { spawn } = require('child_process');
+
+// ─── Config ───
+const TARGET_URL = process.argv[2] || 'http://localhost:3000';
+const WIDTH = 800;
+const HEIGHT = 1280;
+const WS_PORT = 9300;
+const MONITOR_PORT = 9301;
+const CDP_PORT = 9222;
+const QUALITY = parseInt((process.argv.find(a => a.startsWith('--quality=')) || '').split('=')[1] || '75');
+const MAX_FPS = parseInt((process.argv.find(a => a.startsWith('--fps=')) || '').split('=')[1] || '30');
+const HEADLESS = process.argv.includes('--headless');
+
+const clients = new Set();
+let frameCount = 0;
+let bytesSent = 0;
+const t0 = Date.now();
+
+// ─── 1. Launch Chrome ───
+function launchChrome() {
+    return new Promise((resolve, reject) => {
+        const args = [
+            `--remote-debugging-port=${CDP_PORT}`,
+            `--window-size=${WIDTH},${HEIGHT}`,
+            '--disable-gpu', '--no-first-run', '--no-default-browser-check',
+            '--disable-extensions', '--disable-translate', '--disable-sync',
+            '--disable-background-networking', '--disable-default-apps',
+            '--mute-audio', '--no-sandbox',
+        ];
+        if (HEADLESS) args.push('--headless=new');
+        args.push('about:blank');
+
+        const proc = spawn('google-chrome', args, { stdio: ['pipe', 'pipe', 'pipe'] });
+
+        proc.stderr.on('data', d => {
+            if (d.toString().includes('DevTools listening')) resolve(proc);
+        });
+
+        proc.on('error', reject);
+        proc.on('exit', code => { console.log(`[Chrome] exit ${code}`); process.exit(0); });
+
+        // Fallback timeout
+        setTimeout(() => resolve(proc), 4000);
+    });
+}
+
+// ─── 2. WebSocket server for panels/monitor ───
+function startWS() {
+    const wss = new WebSocketServer({ host: '0.0.0.0', port: WS_PORT });
+    wss.on('connection', (ws, req) => {
+        clients.add(ws);
+        console.log(`[WS] +1 panel (${clients.size}) from ${req.socket.remoteAddress}`);
+        ws.on('close', () => { clients.delete(ws); console.log(`[WS] -1 panel (${clients.size})`); });
+        ws.on('message', data => { ws._inputHandler?.(data); });
+    });
+    console.log(`[WS] Panels: ws://0.0.0.0:${WS_PORT}`);
+    return wss;
+}
+
+// ─── 3. Monitor page ───
+function startMonitor() {
+    const html = `<!DOCTYPE html><html><head>
+<title>DreamStack Screencast</title>
+<style>
+*{margin:0;padding:0;box-sizing:border-box}
+body{background:#0a0a0a;display:flex;flex-direction:column;align-items:center;justify-content:center;height:100vh;font-family:system-ui;color:#999}
+canvas{border:1px solid #333;border-radius:8px;max-height:85vh;cursor:crosshair}
+#hud{margin-top:10px;font:13px/1.5 monospace;text-align:center}
+h3{margin-bottom:6px;color:#555;font-size:14px}
+</style></head><body>
+<h3>DreamStack Screencast Monitor</h3>
+<canvas id="c" width="${WIDTH}" height="${HEIGHT}"></canvas>
+<div id="hud">Connecting…</div>
+<script>
+const c=document.getElementById('c'),ctx=c.getContext('2d'),hud=document.getElementById('hud');
+c.style.width=Math.min(${WIDTH},innerWidth*.45)+'px';c.style.height='auto';
+let fr=0,by=0,t=Date.now();
+const ws=new WebSocket('ws://'+location.hostname+':${WS_PORT}');
+ws.binaryType='arraybuffer';
+ws.onopen=()=>{hud.textContent='Connected — waiting for frames…'};
+ws.onmessage=e=>{
+  const buf=new Uint8Array(e.data);
+  if(buf[0]!==0x50)return;
+  const jpeg=buf.slice(9);fr++;by+=jpeg.length;
+  const blob=new Blob([jpeg],{type:'image/jpeg'});
+  const url=URL.createObjectURL(blob);
+  const img=new Image();
+  img.onload=()=>{ctx.drawImage(img,0,0);URL.revokeObjectURL(url)};
+  img.src=url;
+  const now=Date.now();
+  if(now-t>1000){
+    hud.textContent='FPS: '+(fr/((now-t)/1000)).toFixed(1)+' | '+(by/1024/((now-t)/1000)).toFixed(0)+' KB/s | Frame: '+(jpeg.length/1024).toFixed(1)+'KB';
+    fr=0;by=0;t=now;
+  }
+};
+c.addEventListener('click',e=>{
+  const r=c.getBoundingClientRect(),sx=${WIDTH}/r.width,sy=${HEIGHT}/r.height;
+  const x=Math.round((e.clientX-r.left)*sx),y=Math.round((e.clientY-r.top)*sy);
+  const b=new Uint8Array(7);const dv=new DataView(b.buffer);
+  b[0]=0x60;b[1]=0;dv.setUint16(2,x,true);dv.setUint16(4,y,true);b[6]=0;
+  ws.send(b);
+  setTimeout(()=>{const e2=new Uint8Array(7);const d2=new DataView(e2.buffer);e2[0]=0x60;e2[1]=2;d2.setUint16(2,x,true);d2.setUint16(4,y,true);e2[6]=0;ws.send(e2)},50);
+  hud.textContent+=' | Click: ('+x+','+y+')';
+});
+ws.onclose=()=>{hud.textContent='Disconnected — reload to retry'};
+</script></body></html>`;
+
+    http.createServer((_, res) => { res.writeHead(200, { 'Content-Type': 'text/html' }); res.end(html); })
+        .listen(MONITOR_PORT, '0.0.0.0', () => console.log(`[Monitor] http://0.0.0.0:${MONITOR_PORT}`));
+}
+
+// ─── 4. CDP screencast loop ───
+async function startScreencast() {
+    let client;
+    // Retry CDP connect (Chrome may still be starting)
+    for (let i = 0; i < 10; i++) {
+        try {
+            client = await CDP({ port: CDP_PORT });
+            break;
+        } catch {
+            await new Promise(r => setTimeout(r, 1000));
+        }
+    }
+    if (!client) throw new Error('Cannot connect to Chrome CDP');
+
+    const { Page, Input, Emulation } = client;
+
+    await Page.enable();
+    await Emulation.setDeviceMetricsOverride({
+        width: WIDTH, height: HEIGHT, deviceScaleFactor: 1, mobile: true,
+    });
+    await Emulation.setTouchEmulationEnabled({ enabled: true });
+    await Page.navigate({ url: TARGET_URL });
+    await new Promise(r => setTimeout(r, 2000)); // let page load
+
+    // Wire up input forwarding from panels
+    for (const ws of clients) {
+        ws._inputHandler = (data) => handleInput(Buffer.from(data), Input, Page);
+    }
+    // Also for future connections
+    const origAdd = clients.add.bind(clients);
+    clients.add = function (ws) {
+        origAdd(ws);
+        ws._inputHandler = (data) => handleInput(Buffer.from(data), Input, Page);
+    };
+
+    // Start screencast
+    await Page.startScreencast({
+        format: 'jpeg', quality: QUALITY,
+        maxWidth: WIDTH, maxHeight: HEIGHT,
+        everyNthFrame: Math.max(1, Math.round(60 / MAX_FPS)),
+    });
+
+    // Listen for frames via the event API
+    client.on('event', (message) => {
+        if (message.method !== 'Page.screencastFrame') return;
+
+        const { sessionId, data, metadata } = message.params;
+
+        // ACK immediately (fire-and-forget)
+        Page.screencastFrameAck({ sessionId }).catch(() => { });
+
+        frameCount++;
+        const jpegBuf = Buffer.from(data, 'base64');
+        bytesSent += jpegBuf.length;
+
+        // Build frame: [0x50][ts:u32LE][w:u16LE][h:u16LE][jpeg...]
+        const hdr = Buffer.alloc(9);
+        hdr[0] = 0x50;
+        hdr.writeUInt32LE((Date.now() - t0) >>> 0, 1);
+        hdr.writeUInt16LE(metadata.deviceWidth || WIDTH, 5);
+        hdr.writeUInt16LE(metadata.deviceHeight || HEIGHT, 7);
+        const frame = Buffer.concat([hdr, jpegBuf]);
+
+        // Broadcast
+        for (const ws of clients) {
+            if (ws.readyState === 1) ws.send(frame);
+        }
+
+        if (frameCount % 60 === 0) {
+            const elapsed = (Date.now() - t0) / 1000;
+            console.log(`[Cast] #${frameCount} | ${(jpegBuf.length / 1024).toFixed(1)}KB | avg ${(bytesSent / 1024 / elapsed).toFixed(0)} KB/s | ${clients.size} panels`);
+        }
+    });
+
+    console.log(`[CDP] Casting ${TARGET_URL} → ${WIDTH}×${HEIGHT} @ q${QUALITY}`);
+}
+
+// ─── Input handler ───
+function handleInput(buf, Input, Page) {
+    if (buf.length < 1) return;
+    const t = buf[0];
+
+    if (t === 0x60 && buf.length >= 7) {
+        const phase = buf[1];
+        const x = buf.readUInt16LE(2), y = buf.readUInt16LE(4);
+        const type = phase === 0 ? 'touchStart' : phase === 1 ? 'touchMove' : 'touchEnd';
+        Input.dispatchTouchEvent({
+            type, touchPoints: [{ x, y, id: buf[6] || 0, radiusX: 10, radiusY: 10, force: phase === 2 ? 0 : 1 }]
+        }).catch(() => { });
+    }
+
+    if (t === 0x61 && buf.length >= 6) {
+        const x = buf.readUInt16LE(1), y = buf.readUInt16LE(3);
+        Input.dispatchMouseEvent({ type: 'mousePressed', x, y, button: 'left', clickCount: 1 }).catch(() => { });
+        setTimeout(() => Input.dispatchMouseEvent({ type: 'mouseReleased', x, y, button: 'left', clickCount: 1 }).catch(() => { }), 50);
+    }
+
+    if (t === 0x63 && buf.length >= 3) {
+        const len = buf.readUInt16LE(1);
+        const url = buf.slice(3, 3 + len).toString();
+        Page.navigate({ url }).catch(() => { });
+        console.log(`[Nav] → ${url}`);
+    }
+}
+
+// ─── Main ───
+async function main() {
+    console.log(`\n  DreamStack Screencast`);
+    console.log(`  ─────────────────────`);
+    console.log(`  URL:       ${TARGET_URL}`);
+    console.log(`  Viewport:  ${WIDTH}×${HEIGHT}`);
+    console.log(`  Quality:   ${QUALITY}%  FPS: ${MAX_FPS}`);
+    console.log(`  Headless:  ${HEADLESS}\n`);
+
+    const chrome = await launchChrome();
+    startWS();
+    startMonitor();
+    await startScreencast();
+
+    console.log(`\n  ✓ Streaming! Panels → ws://0.0.0.0:${WS_PORT}`);
+    console.log(`  ✓ Monitor  → http://localhost:${MONITOR_PORT}\n`);
+
+    process.on('SIGINT', () => {
+        console.log('\n[Stop]');
+        chrome.kill();
+        process.exit(0);
+    });
+}
+
+main().catch(err => { console.error('Fatal:', err); process.exit(1); });

engine/ds-screencast/node_modules/.bin/chrome-remote-interface

@@ -0,0 +1 @@
+../chrome-remote-interface/bin/client.js

engine/ds-screencast/node_modules/.package-lock.json

@@ -0,0 +1,69 @@
+{
+  "name": "ds-screencast",
+  "version": "1.0.0",
+  "lockfileVersion": 3,
+  "requires": true,
+  "packages": {
+    "node_modules/chrome-remote-interface": {
+      "version": "0.34.0",
+      "resolved": "https://registry.npmjs.org/chrome-remote-interface/-/chrome-remote-interface-0.34.0.tgz",
+      "integrity": "sha512-rTTcTZ3zemx8I+nvBii7d8BAF0Ms8LLEroypfvwwZOwSpyNGLE28nStXyCA6VwGp2YSQfmCrQH21F/E+oBFvMw==",
+      "license": "MIT",
+      "dependencies": {
+        "commander": "2.11.x",
+        "ws": "^7.2.0"
+      },
+      "bin": {
+        "chrome-remote-interface": "bin/client.js"
+      }
+    },
+    "node_modules/chrome-remote-interface/node_modules/ws": {
+      "version": "7.5.10",
+      "resolved": "https://registry.npmjs.org/ws/-/ws-7.5.10.tgz",
+      "integrity": "sha512-+dbF1tHwZpXcbOJdVOkzLDxZP1ailvSxM6ZweXTegylPny803bFhA+vqBYw4s31NSAk4S2Qz+AKXK9a4wkdjcQ==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=8.3.0"
+      },
+      "peerDependencies": {
+        "bufferutil": "^4.0.1",
+        "utf-8-validate": "^5.0.2"
+      },
+      "peerDependenciesMeta": {
+        "bufferutil": {
+          "optional": true
+        },
+        "utf-8-validate": {
+          "optional": true
+        }
+      }
+    },
+    "node_modules/commander": {
+      "version": "2.11.0",
+      "resolved": "https://registry.npmjs.org/commander/-/commander-2.11.0.tgz",
+      "integrity": "sha512-b0553uYA5YAEGgyYIGYROzKQ7X5RAqedkfjiZxwi0kL1g3bOaBNNZfYkzt/CL0umgD5wc9Jec2FbB98CjkMRvQ==",
+      "license": "MIT"
+    },
+    "node_modules/ws": {
+      "version": "8.19.0",
+      "resolved": "https://registry.npmjs.org/ws/-/ws-8.19.0.tgz",
+      "integrity": "sha512-blAT2mjOEIi0ZzruJfIhb3nps74PRWTCz1IjglWEEpQl5XS/UNama6u2/rjFkDDouqr4L67ry+1aGIALViWjDg==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=10.0.0"
+      },
+      "peerDependencies": {
+        "bufferutil": "^4.0.1",
+        "utf-8-validate": ">=5.0.2"
+      },
+      "peerDependenciesMeta": {
+        "bufferutil": {
+          "optional": true
+        },
+        "utf-8-validate": {
+          "optional": true
+        }
+      }
+    }
+  }
+}

engine/ds-screencast/node_modules/chrome-remote-interface/LICENSE

@@ -0,0 +1,18 @@
+Copyright (c) 2026 Andrea Cardaci <cyrus.and@gmail.com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

engine/ds-screencast/node_modules/chrome-remote-interface/README.md

@@ -0,0 +1,991 @@
+# chrome-remote-interface
+
+[![CI status](https://github.com/cyrus-and/chrome-remote-interface/actions/workflows/ci.yml/badge.svg)](https://github.com/cyrus-and/chrome-remote-interface/actions?query=workflow:CI)
+
+[Chrome Debugging Protocol] interface that helps to instrument Chrome (or any
+other suitable [implementation](#implementations)) by providing a simple
+abstraction of commands and notifications using a straightforward JavaScript
+API.
+
+## Sample API usage
+
+The following snippet loads `https://github.com` and dumps every request made:
+
+```js
+const CDP = require('chrome-remote-interface');
+
+async function example() {
+    let client;
+    try {
+        // connect to endpoint
+        client = await CDP();
+        // extract domains
+        const {Network, Page} = client;
+        // setup handlers
+        Network.requestWillBeSent((params) => {
+            console.log(params.request.url);
+        });
+        // enable events then start!
+        await Network.enable();
+        await Page.enable();
+        await Page.navigate({url: 'https://github.com'});
+        await Page.loadEventFired();
+    } catch (err) {
+        console.error(err);
+    } finally {
+        if (client) {
+            await client.close();
+        }
+    }
+}
+
+example();
+```
+
+Find more examples in the [wiki]. You may also want to take a look at the [FAQ].
+
+[wiki]: https://github.com/cyrus-and/chrome-remote-interface/wiki
+[async-await-example]: https://github.com/cyrus-and/chrome-remote-interface/wiki/Async-await-example
+[FAQ]: https://github.com/cyrus-and/chrome-remote-interface#faq
+
+## Installation
+
+    npm install chrome-remote-interface
+
+Install globally (`-g`) to just use the [bundled client](#bundled-client).
+
+## Implementations
+
+This module should work with every application implementing the
+[Chrome Debugging Protocol]. In particular, it has been tested against the
+following implementations:
+
+Implementation             | Protocol version   | [Protocol] | [List] | [New] | [Activate] | [Close] | [Version]
+---------------------------|--------------------|------------|--------|-------|------------|---------|-----------
+[Chrome][1.1]              | [tip-of-tree][1.2] | yes¹       | yes    | yes   | yes        | yes     | yes
+[Opera][2.1]               | [tip-of-tree][2.2] | yes        | yes    | yes   | yes        | yes     | yes
+[Node.js][3.1] ([v6.3.0]+) | [node][3.2]        | yes        | no     | no    | no         | no      | yes
+[Safari (iOS)][4.1]        | [*partial*][4.2]   | no         | yes    | no    | no         | no      | no
+[Edge][5.1]                | [*partial*][5.2]   | yes        | yes    | no    | no         | no      | yes
+[Firefox (Nightly)][6.1]   | [*partial*][6.2]   | yes        | yes    | no    | yes        | yes     | yes
+
+¹ Not available on [Chrome for Android][chrome-mobile-protocol], hence a local version of the protocol must be used.
+
+[chrome-mobile-protocol]: https://bugs.chromium.org/p/chromium/issues/detail?id=824626#c4
+
+[1.1]: #chromechromium
+[1.2]: https://chromedevtools.github.io/devtools-protocol/tot/
+
+[2.1]: #opera
+[2.2]: https://chromedevtools.github.io/devtools-protocol/tot/
+
+[3.1]: #nodejs
+[3.2]: https://chromedevtools.github.io/devtools-protocol/v8/
+
+[4.1]: #safari-ios
+[4.2]: http://trac.webkit.org/browser/trunk/Source/JavaScriptCore/inspector/protocol
+
+[5.1]: #edge
+[5.2]: https://docs.microsoft.com/en-us/microsoft-edge/devtools-protocol/0.1/domains/
+
+[6.1]: #firefox-nightly
+[6.2]: https://firefox-source-docs.mozilla.org/remote/index.html
+
+[v6.3.0]: https://nodejs.org/en/blog/release/v6.3.0/
+
+[Protocol]: #cdpprotocoloptions-callback
+[List]: #cdplistoptions-callback
+[New]: #cdpnewoptions-callback
+[Activate]: #cdpactivateoptions-callback
+[Close]: #cdpcloseoptions-callback
+[Version]: #cdpversionoptions-callback
+
+The meaning of *target* varies according to the implementation, for example,
+each Chrome tab represents a target whereas for Node.js a target is the
+currently inspected script.
+
+## Setup
+
+An instance of either Chrome itself or another implementation needs to be
+running on a known port in order to use this module (defaults to
+`localhost:9222`).
+
+### Chrome/Chromium
+
+#### Desktop
+
+Start Chrome with the `--remote-debugging-port` option, for example:
+
+    google-chrome --remote-debugging-port=9222
+
+##### Headless
+
+Since version 59, additionally use the `--headless` option, for example:
+
+    google-chrome --headless --remote-debugging-port=9222
+
+#### Android
+
+Plug the device and make sure to authorize the connection from the device itself. Then
+enable the port forwarding, for example:
+
+    adb -d forward tcp:9222 localabstract:chrome_devtools_remote
+
+After that you should be able to use `http://127.0.0.1:9222` as usual, but note that in
+Android, Chrome does not have its own protocol available, so a local version must be used.
+See [here](#chrome-debugging-protocol-versions) for more information.
+
+##### WebView
+
+In order to be inspectable, a WebView must
+be [configured for debugging][webview] and the corresponding process ID must be
+known. There are several ways to obtain it, for example:
+
+    adb shell grep -a webview_devtools_remote /proc/net/unix
+
+Finally, port forwarding can be enabled as follows:
+
+    adb forward tcp:9222 localabstract:webview_devtools_remote_<pid>
+
+[webview]: https://developers.google.com/web/tools/chrome-devtools/remote-debugging/webviews#configure_webviews_for_debugging
+
+### Opera
+
+Start Opera with the `--remote-debugging-port` option, for example:
+
+    opera --remote-debugging-port=9222
+
+### Node.js
+
+Start Node.js with the `--inspect` option, for example:
+
+    node --inspect=9222 script.js
+
+### Safari (iOS)
+
+Install and run the [iOS WebKit Debug Proxy][iwdp]. Then use it with the `local`
+option set to `true` to use the local version of the protocol or pass a custom
+descriptor upon connection (`protocol` option).
+
+[iwdp]: https://github.com/google/ios-webkit-debug-proxy
+
+### Edge
+
+Start Edge with the `--devtools-server-port` option, for example:
+
+    MicrosoftEdge.exe --devtools-server-port 9222 about:blank
+
+Please find more information [here][edge-devtools].
+
+[edge-devtools]: https://docs.microsoft.com/en-us/microsoft-edge/devtools-protocol/
+
+### Firefox (Nightly)
+
+Start Firefox with the `--remote-debugging-port` option, for example:
+
+    firefox --remote-debugging-port 9222
+
+Bear in mind that this is an experimental feature of Firefox.
+
+## Bundled client
+
+This module comes with a bundled client application that can be used to
+interactively control a remote instance.
+
+### Target management
+
+The bundled client exposes subcommands to interact with the HTTP frontend
+(e.g., [List](#cdplistoptions-callback), [New](#cdpnewoptions-callback), etc.),
+run with `--help` to display the list of available options.
+
+Here are some examples:
+
+```js
+$ chrome-remote-interface new 'http://example.com'
+{
+    "description": "",
+    "devtoolsFrontendUrl": "/devtools/inspector.html?ws=localhost:9222/devtools/page/b049bb56-de7d-424c-a331-6ae44cf7ae01",
+    "id": "b049bb56-de7d-424c-a331-6ae44cf7ae01",
+    "thumbnailUrl": "/thumb/b049bb56-de7d-424c-a331-6ae44cf7ae01",
+    "title": "",
+    "type": "page",
+    "url": "http://example.com/",
+    "webSocketDebuggerUrl": "ws://localhost:9222/devtools/page/b049bb56-de7d-424c-a331-6ae44cf7ae01"
+}
+$ chrome-remote-interface close 'b049bb56-de7d-424c-a331-6ae44cf7ae01'
+```
+
+### Inspection
+
+Using the `inspect` subcommand it is possible to perform [command execution](#clientdomainmethodparams-callback)
+and [event binding](#clientdomaineventcallback) in a REPL fashion that provides completion.
+
+Here is a sample session:
+
+```js
+$ chrome-remote-interface inspect
+>>> Runtime.evaluate({expression: 'window.location.toString()'})
+{ result: { type: 'string', value: 'about:blank' } }
+>>> Page.enable()
+{}
+>>> Page.loadEventFired(console.log)
+[Function]
+>>> Page.navigate({url: 'https://github.com'})
+{ frameId: 'E1657E22F06E6E0BE13DFA8130C20298',
+  loaderId: '439236ADE39978F98C20E8939A32D3A5' }
+>>> { timestamp: 7454.721299 } // from Page.loadEventFired
+>>> Runtime.evaluate({expression: 'window.location.toString()'})
+{ result: { type: 'string', value: 'https://github.com/' } }
+```
+
+Additionally there are some custom commands available:
+
+```js
+>>> .help
+[...]
+.reset    Remove all the registered event handlers
+.target   Display the current target
+```
+
+## Embedded documentation
+
+In both the REPL and the regular API every object of the protocol is *decorated*
+with the meta information found within the descriptor. In addition The
+`category` field is added, which determines if the member is a `command`, an
+`event` or a `type`.
+
+For example to learn how to call `Page.navigate`:
+
+```js
+>>> Page.navigate
+{ [Function]
+  category: 'command',
+  parameters: { url: { type: 'string', description: 'URL to navigate the page to.' } },
+  returns:
+   [ { name: 'frameId',
+       '$ref': 'FrameId',
+       hidden: true,
+       description: 'Frame id that will be navigated.' } ],
+  description: 'Navigates current page to the given URL.',
+  handlers: [ 'browser', 'renderer' ] }
+```
+
+To learn about the parameters returned by the `Network.requestWillBeSent` event:
+
+```js
+>>> Network.requestWillBeSent
+{ [Function]
+  category: 'event',
+  description: 'Fired when page is about to send HTTP request.',
+  parameters:
+   { requestId: { '$ref': 'RequestId', description: 'Request identifier.' },
+     frameId:
+      { '$ref': 'Page.FrameId',
+        description: 'Frame identifier.',
+        hidden: true },
+     loaderId: { '$ref': 'LoaderId', description: 'Loader identifier.' },
+     documentURL:
+      { type: 'string',
+        description: 'URL of the document this request is loaded for.' },
+     request: { '$ref': 'Request', description: 'Request data.' },
+     timestamp: { '$ref': 'Timestamp', description: 'Timestamp.' },
+     wallTime:
+      { '$ref': 'Timestamp',
+        hidden: true,
+        description: 'UTC Timestamp.' },
+     initiator: { '$ref': 'Initiator', description: 'Request initiator.' },
+     redirectResponse:
+      { optional: true,
+        '$ref': 'Response',
+        description: 'Redirect response data.' },
+     type:
+      { '$ref': 'Page.ResourceType',
+        optional: true,
+        hidden: true,
+        description: 'Type of this resource.' } } }
+```
+
+To inspect the `Network.Request` (note that unlike commands and events, types
+are named in upper camel case) type:
+
+```js
+>>> Network.Request
+{ category: 'type',
+  id: 'Request',
+  type: 'object',
+  description: 'HTTP request data.',
+  properties:
+   { url: { type: 'string', description: 'Request URL.' },
+     method: { type: 'string', description: 'HTTP request method.' },
+     headers: { '$ref': 'Headers', description: 'HTTP request headers.' },
+     postData:
+      { type: 'string',
+        optional: true,
+        description: 'HTTP POST request data.' },
+     mixedContentType:
+      { optional: true,
+        type: 'string',
+        enum: [Object],
+        description: 'The mixed content status of the request, as defined in http://www.w3.org/TR/mixed-content/' },
+     initialPriority:
+      { '$ref': 'ResourcePriority',
+        description: 'Priority of the resource request at the time request is sent.' } } }
+```
+
+## Chrome Debugging Protocol versions
+
+By default `chrome-remote-interface` *asks* the remote instance to provide its
+own protocol.
+
+This behavior can be changed by setting the `local` option to `true`
+upon [connection](#cdpoptions-callback), in which case the [local version] of
+the protocol descriptor is used. This file is manually updated from time to time
+using `scripts/update-protocol.sh` and pushed to this repository.
+
+To further override the above behavior there are basically two options:
+
+- pass a custom protocol descriptor upon [connection](#cdpoptions-callback)
+  (`protocol` option);
+
+- use the *raw* version of the [commands](#clientsendmethod-params-callback)
+  and [events](#event-domainmethod) interface to use bleeding-edge features that
+  do not appear in the [local version] of the protocol descriptor;
+
+[local version]: lib/protocol.json
+
+## Browser usage
+
+This module is able to run within a web context, with obvious limitations
+though, namely external HTTP requests
+([List](#cdplistoptions-callback), [New](#cdpnewoptions-callback), etc.) cannot
+be performed directly, for this reason the user must provide a global
+`criRequest` in order to use them:
+
+```js
+function criRequest(options, callback) {}
+```
+
+`options` is the same object used by the Node.js `http` module and `callback` is
+a function taking two arguments: `err` (JavaScript `Error` object or `null`) and
+`data` (string result).
+
+### Using [webpack](https://webpack.github.io/)
+
+It just works, simply require this module:
+
+```js
+const CDP = require('chrome-remote-interface');
+```
+
+### Using *vanilla* JavaScript
+
+To generate a JavaScript file that can be used with a `<script>` element:
+
+1. run `npm install` from the root directory;
+
+2. manually run webpack with:
+
+        TARGET=var npm run webpack
+
+3. use as:
+
+    ```html
+    <script>
+      function criRequest(options, callback) { /*...*/ }
+    </script>
+    <script src="chrome-remote-interface.js"></script>
+    ```
+
+## TypeScript Support
+
+[TypeScript][] definitions are kindly provided by [Khairul Azhar Kasmiran][] and [Seth Westphal][], and can be installed from [DefinitelyTyped][]:
+
+```
+npm install --save-dev @types/chrome-remote-interface
+```
+
+Note that the TypeScript definitions are automatically generated from the npm package `devtools-protocol@0.0.927104`. For other versions of devtools-protocol:
+
+1. Install patch-package using [the instructions given](https://github.com/ds300/patch-package#set-up).
+2. Copy the contents of the corresponding https://github.com/ChromeDevTools/devtools-protocol/tree/master/types folder (according to commit) into `node_modules/devtools-protocol/types`.
+3. Run `npx patch-package devtools-protocol` so that the changes persist across an `npm install`.
+
+[TypeScript]: https://www.typescriptlang.org/
+[Khairul Azhar Kasmiran]: https://github.com/kazarmy
+[Seth Westphal]: https://github.com/westy92
+[DefinitelyTyped]: https://github.com/DefinitelyTyped/DefinitelyTyped/tree/master/types/chrome-remote-interface
+
+## API
+
+The API consists of three parts:
+
+- *DevTools* methods (for those [implementations](#implementations) that support
+  them, e.g., [List](#cdplistoptions-callback), [New](#cdpnewoptions-callback),
+  etc.);
+
+- [connection](#cdpoptions-callback) establishment;
+
+- the actual [protocol interaction](#class-cdp).
+
+### CDP([options], [callback])
+
+Connects to a remote instance using the [Chrome Debugging Protocol].
+
+`options` is an object with the following optional properties:
+
+- `host`: HTTP frontend host. Defaults to `localhost`;
+- `port`: HTTP frontend port. Defaults to `9222`;
+- `secure`: HTTPS/WSS frontend. Defaults to `false`;
+- `useHostName`: do not perform a DNS lookup of the host. Defaults to `false`;
+- `alterPath`: a `function` taking and returning the path fragment of a URL
+  before that a request happens. Defaults to the identity function;
+- `target`: determines which target this client should attach to. The behavior
+  changes according to the type:
+
+  - a `function` that takes the array returned by the `List` method and returns
+    a target or its numeric index relative to the array;
+  - a target `object` like those returned by the `New` and `List` methods;
+  - a `string` representing the raw WebSocket URL, in this case `host` and
+    `port` are not used to fetch the target list, yet they are used to complete
+    the URL if relative;
+  - a `string` representing the target id.
+
+  Defaults to a function which returns the first available target according to
+  the implementation (note that at most one connection can be established to the
+  same target);
+- `protocol`: [Chrome Debugging Protocol] descriptor object. Defaults to use the
+  protocol chosen according to the `local` option;
+- `local`: a boolean indicating whether the protocol must be fetched *remotely*
+  or if the local version must be used. It has no effect if the `protocol`
+  option is set. Defaults to `false`.
+
+These options are also valid properties of all the instances of the `CDP`
+class. In addition to that, the `webSocketUrl` field contains the currently used
+WebSocket URL.
+
+`callback` is a listener automatically added to the `connect` event of the
+returned `EventEmitter`. When `callback` is omitted a `Promise` object is
+returned which becomes fulfilled if the `connect` event is triggered and
+rejected if the `error` event is triggered.
+
+The `EventEmitter` supports the following events:
+
+#### Event: 'connect'
+
+```js
+function (client) {}
+```
+
+Emitted when the connection to the WebSocket is established.
+
+`client` is an instance of the `CDP` class.
+
+#### Event: 'error'
+
+```js
+function (err) {}
+```
+
+Emitted when `http://host:port/json` cannot be reached or if it is not possible
+to connect to the WebSocket.
+
+`err` is an instance of `Error`.
+
+### CDP.Protocol([options], [callback])
+
+Fetch the [Chrome Debugging Protocol] descriptor.
+
+`options` is an object with the following optional properties:
+
+- `host`: HTTP frontend host. Defaults to `localhost`;
+- `port`: HTTP frontend port. Defaults to `9222`;
+- `secure`: HTTPS/WSS frontend. Defaults to `false`;
+- `useHostName`: do not perform a DNS lookup of the host. Defaults to `false`;
+- `alterPath`: a `function` taking and returning the path fragment of a URL
+  before that a request happens. Defaults to the identity function;
+- `local`: a boolean indicating whether the protocol must be fetched *remotely*
+  or if the local version must be returned. Defaults to `false`.
+
+`callback` is executed when the protocol is fetched, it gets the following
+arguments:
+
+- `err`: a `Error` object indicating the success status;
+- `protocol`: the [Chrome Debugging Protocol] descriptor.
+
+When `callback` is omitted a `Promise` object is returned.
+
+For example:
+
+```js
+const CDP = require('chrome-remote-interface');
+CDP.Protocol((err, protocol) => {
+    if (!err) {
+        console.log(JSON.stringify(protocol, null, 4));
+    }
+});
+```
+
+### CDP.List([options], [callback])
+
+Request the list of the available open targets/tabs of the remote instance.
+
+`options` is an object with the following optional properties:
+
+- `host`: HTTP frontend host. Defaults to `localhost`;
+- `port`: HTTP frontend port. Defaults to `9222`;
+- `secure`: HTTPS/WSS frontend. Defaults to `false`;
+- `useHostName`: do not perform a DNS lookup of the host. Defaults to `false`;
+- `alterPath`: a `function` taking and returning the path fragment of a URL
+  before that a request happens. Defaults to the identity function.
+
+`callback` is executed when the list is correctly received, it gets the
+following arguments:
+
+- `err`: a `Error` object indicating the success status;
+- `targets`: the array returned by `http://host:port/json/list` containing the
+  target list.
+
+When `callback` is omitted a `Promise` object is returned.
+
+For example:
+
+```js
+const CDP = require('chrome-remote-interface');
+CDP.List((err, targets) => {
+    if (!err) {
+        console.log(targets);
+    }
+});
+```
+
+### CDP.New([options], [callback])
+
+Create a new target/tab in the remote instance.
+
+`options` is an object with the following optional properties:
+
+- `host`: HTTP frontend host. Defaults to `localhost`;
+- `port`: HTTP frontend port. Defaults to `9222`;
+- `secure`: HTTPS/WSS frontend. Defaults to `false`;
+- `useHostName`: do not perform a DNS lookup of the host. Defaults to `false`;
+- `alterPath`: a `function` taking and returning the path fragment of a URL
+  before that a request happens. Defaults to the identity function;
+- `url`: URL to load in the new target/tab. Defaults to `about:blank`.
+
+`callback` is executed when the target is created, it gets the following
+arguments:
+
+- `err`: a `Error` object indicating the success status;
+- `target`: the object returned by `http://host:port/json/new` containing the
+  target.
+
+When `callback` is omitted a `Promise` object is returned.
+
+For example:
+
+```js
+const CDP = require('chrome-remote-interface');
+CDP.New((err, target) => {
+    if (!err) {
+        console.log(target);
+    }
+});
+```
+
+### CDP.Activate([options], [callback])
+
+Activate an open target/tab of the remote instance.
+
+`options` is an object with the following properties:
+
+- `host`: HTTP frontend host. Defaults to `localhost`;
+- `port`: HTTP frontend port. Defaults to `9222`;
+- `secure`: HTTPS/WSS frontend. Defaults to `false`;
+- `useHostName`: do not perform a DNS lookup of the host. Defaults to `false`;
+- `alterPath`: a `function` taking and returning the path fragment of a URL
+  before that a request happens. Defaults to the identity function;
+- `id`: Target id. Required, no default.
+
+`callback` is executed when the response to the activation request is
+received. It gets the following arguments:
+
+- `err`: a `Error` object indicating the success status;
+
+When `callback` is omitted a `Promise` object is returned.
+
+For example:
+
+```js
+const CDP = require('chrome-remote-interface');
+CDP.Activate({id: 'CC46FBFA-3BDA-493B-B2E4-2BE6EB0D97EC'}, (err) => {
+    if (!err) {
+        console.log('target is activated');
+    }
+});
+```
+
+### CDP.Close([options], [callback])
+
+Close an open target/tab of the remote instance.
+
+`options` is an object with the following properties:
+
+- `host`: HTTP frontend host. Defaults to `localhost`;
+- `port`: HTTP frontend port. Defaults to `9222`;
+- `secure`: HTTPS/WSS frontend. Defaults to `false`;
+- `useHostName`: do not perform a DNS lookup of the host. Defaults to `false`;
+- `alterPath`: a `function` taking and returning the path fragment of a URL
+  before that a request happens. Defaults to the identity function;
+- `id`: Target id. Required, no default.
+
+`callback` is executed when the response to the close request is received. It
+gets the following arguments:
+
+- `err`: a `Error` object indicating the success status;
+
+When `callback` is omitted a `Promise` object is returned.
+
+For example:
+
+```js
+const CDP = require('chrome-remote-interface');
+CDP.Close({id: 'CC46FBFA-3BDA-493B-B2E4-2BE6EB0D97EC'}, (err) => {
+    if (!err) {
+        console.log('target is closing');
+    }
+});
+```
+
+Note that the callback is fired when the target is *queued* for removal, but the
+actual removal will occur asynchronously.
+
+### CDP.Version([options], [callback])
+
+Request version information from the remote instance.
+
+`options` is an object with the following optional properties:
+
+- `host`: HTTP frontend host. Defaults to `localhost`;
+- `port`: HTTP frontend port. Defaults to `9222`;
+- `secure`: HTTPS/WSS frontend. Defaults to `false`;
+- `useHostName`: do not perform a DNS lookup of the host. Defaults to `false`;
+- `alterPath`: a `function` taking and returning the path fragment of a URL
+  before that a request happens. Defaults to the identity function.
+
+`callback` is executed when the version information is correctly received, it
+gets the following arguments:
+
+- `err`: a `Error` object indicating the success status;
+- `info`: a JSON object returned by `http://host:port/json/version` containing
+  the version information.
+
+When `callback` is omitted a `Promise` object is returned.
+
+For example:
+
+```js
+const CDP = require('chrome-remote-interface');
+CDP.Version((err, info) => {
+    if (!err) {
+        console.log(info);
+    }
+});
+```
+
+### Class: CDP
+
+#### Event: 'event'
+
+```js
+function (message) {}
+```
+
+Emitted when the remote instance sends any notification through the WebSocket.
+
+`message` is the object received, it has the following properties:
+
+- `method`: a string describing the notification (e.g.,
+  `'Network.requestWillBeSent'`);
+- `params`: an object containing the payload;
+- `sessionId`: an optional string representing the session identifier.
+
+Refer to the [Chrome Debugging Protocol] specification for more information.
+
+For example:
+
+```js
+client.on('event', (message) => {
+    if (message.method === 'Network.requestWillBeSent') {
+        console.log(message.params);
+    }
+});
+```
+
+#### Event: '`<domain>`.`<method>`'
+
+```js
+function (params, sessionId) {}
+```
+
+Emitted when the remote instance sends a notification for `<domain>.<method>`
+through the WebSocket.
+
+`params` is an object containing the payload.
+
+`sessionId` is an optional string representing the session identifier.
+
+This is just a utility event which allows to easily listen for specific
+notifications (see [`'event'`](#event-event)), for example:
+
+```js
+client.on('Network.requestWillBeSent', console.log);
+```
+
+Additionally, the equivalent `<domain>.on('<method>', ...)` syntax is available, for example:
+
+```js
+client.Network.on('requestWillBeSent', console.log);
+```
+
+#### Event: '`<domain>`.`<method>`.`<sessionId>`'
+
+```js
+function (params, sessionId) {}
+```
+
+Equivalent to the following but only for those events belonging to the given `session`:
+
+```js
+client.on('<domain>.<event>', callback);
+```
+
+#### Event: 'ready'
+
+```js
+function () {}
+```
+
+Emitted every time that there are no more pending commands waiting for a
+response from the remote instance. The interaction is asynchronous so the only
+way to serialize a sequence of commands is to use the callback provided by
+the [`send`](#clientsendmethod-params-callback) method. This event acts as a
+barrier and it is useful to avoid the *callback hell* in certain simple
+situations.
+
+Users are encouraged to extensively check the response of each method and should
+prefer the promises API when dealing with complex asynchronous program flows.
+
+For example to load a URL only after having enabled the notifications of both
+`Network` and `Page` domains:
+
+```js
+client.Network.enable();
+client.Page.enable();
+client.once('ready', () => {
+    client.Page.navigate({url: 'https://github.com'});
+});
+```
+
+In this particular case, not enforcing this kind of serialization may cause that
+the remote instance does not properly deliver the desired notifications the
+client.
+
+
+#### Event: 'disconnect'
+
+```js
+function () {}
+```
+
+Emitted when the instance closes the WebSocket connection.
+
+This may happen for example when the user opens DevTools or when the tab is
+closed.
+
+#### client.send(method, [params], [sessionId], [callback])
+
+Issue a command to the remote instance.
+
+`method` is a string describing the command.
+
+`params` is an object containing the payload.
+
+`sessionId` is a string representing the session identifier.
+
+`callback` is executed when the remote instance sends a response to this
+command, it gets the following arguments:
+
+- `error`: a boolean value indicating the success status, as reported by the
+  remote instance;
+- `response`: an object containing either the response (`result` field, if
+  `error === false`) or the indication of the error (`error` field, if `error
+  === true`).
+
+When `callback` is omitted a `Promise` object is returned instead, with the
+fulfilled/rejected states implemented according to the `error` parameter.  The
+`Error` object con be an instance of [`ProtocolError`](#cdpprotocolerror) for
+protocol invocation errors. Alternatively, in case of low-level WebSocket
+errors, the `error` parameter contains the originating `Error` object.
+
+Note that the field `id` mentioned in the [Chrome Debugging Protocol]
+specification is managed internally and it is not exposed to the user.
+
+For example:
+
+```js
+client.send('Page.navigate', {url: 'https://github.com'}, console.log);
+```
+
+#### client.`<domain>`.`<method>`([params], [sessionId], [callback])
+
+Just a shorthand for:
+
+```js
+client.send('<domain>.<method>', params, sessionId, callback);
+```
+
+For example:
+
+```js
+client.Page.navigate({url: 'https://github.com'}, console.log);
+```
+
+#### client.`<domain>`.`<event>`([sessionId], [callback])
+
+Just a shorthand for:
+
+```js
+client.on('<domain>.<event>[.<sessionId>]', callback);
+```
+
+When `callback` is omitted the event is registered only once and a `Promise`
+object is returned. Notice though that in this case the optional `sessionId` usually passed to `callback` is not returned.
+
+When `callback` is provided, it returns a function that can be used to
+unsubscribe `callback` from the event, it can be useful when anonymous functions
+are used as callbacks.
+
+For example:
+
+```js
+const unsubscribe = client.Network.requestWillBeSent((params, sessionId) => {
+    console.log(params.request.url);
+});
+unsubscribe();
+```
+
+#### client.close([callback])
+
+Close the connection to the remote instance.
+
+`callback` is executed when the WebSocket is successfully closed.
+
+When `callback` is omitted a `Promise` object is returned.
+
+#### client['`<domain>`.`<name>`']
+
+Just a shorthand for:
+
+```js
+client.<domain>.<name>
+```
+
+Where `<name>` can be a command, an event, or a type.
+
+### CDP.ProtocolError
+
+Error returned by the [`send`](#clientsendmethod-params-callback) method in case Chrome experienced issues in the protocol invocation. It exposes the following fields:
+
+- `request`: the raw request object containing the `method`, `params`, and `sessionId` fields;
+- `response`: the raw response from Chrome, usually containing the `code`, `message`, and `data` fields.
+
+## FAQ
+
+### Invoking `Domain.methodOrEvent` I obtain `Domain.methodOrEvent is not a function`
+
+This means that you are trying to use a method or an event that are not present
+in the protocol descriptor that you are using.
+
+If the protocol is fetched from Chrome directly, then it means that this version
+of Chrome does not support that feature. The solution is to update it.
+
+If you are using a local or custom version of the protocol, then it means that
+the version is obsolete. The solution is to provide an up-to-date one, or if you
+are using the protocol embedded in chrome-remote-interface, make sure to be
+running the latest version of this module. In case the embedded protocol is
+obsolete, please [file an issue](https://github.com/cyrus-and/chrome-remote-interface/issues/new).
+
+See [here](#chrome-debugging-protocol-versions) for more information.
+
+### Invoking `Domain.method` I obtain `Domain.method wasn't found`
+
+This means that you are providing a custom or local protocol descriptor
+(`CDP({protocol: customProtocol})`) which declares `Domain.method` while the
+Chrome version that you are using does not support it.
+
+To inspect the currently available protocol descriptor use:
+
+```
+$ chrome-remote-interface inspect
+```
+
+See [here](#chrome-debugging-protocol-versions) for more information.
+
+### Why my program stalls or behave unexpectedly if I run Chrome in a Docker container?
+
+This happens because the size of `/dev/shm` is set to 64MB by default in Docker
+and may not be enough for Chrome to navigate certain web pages.
+
+You can change this value by running your container with, say,
+`--shm-size=256m`.
+
+### Using `Runtime.evaluate` with `awaitPromise: true` I sometimes obtain `Error: Promise was collected`
+
+This is thrown by `Runtime.evaluate` when the browser-side promise gets
+*collected* by the Chrome's garbage collector, this happens when the whole
+JavaScript execution environment is invalidated, e.g., a when page is navigated
+or reloaded while a promise is still waiting to be resolved.
+
+Here is an example:
+
+```
+$ chrome-remote-interface inspect
+>>> Runtime.evaluate({expression: `new Promise(() => {})`, awaitPromise: true})
+>>> Page.reload() // then wait several seconds
+{ result: {} }
+{ error: { code: -32000, message: 'Promise was collected' } }
+```
+
+To fix this, just make sure there are no pending promises before closing,
+reloading, etc. a page.
+
+### How does this compare to Puppeteer?
+
+[Puppeteer] is an additional high-level API built upon the [Chrome Debugging
+Protocol] which, among the other things, may start and use a bundled version of
+Chromium instead of the one installed on your system. Use it if its API meets
+your needs as it would probably be easier to work with.
+
+chrome-remote-interface instead is just a general purpose 1:1 Node.js binding
+for the [Chrome Debugging Protocol]. Use it if you need all the power of the raw
+protocol, e.g., to implement your own high-level API.
+
+See [#240] for a more thorough discussion.
+
+[Puppeteer]: https://github.com/GoogleChrome/puppeteer
+[#240]: https://github.com/cyrus-and/chrome-remote-interface/issues/240
+
+## Contributors
+
+- [Andrey Sidorov](https://github.com/sidorares)
+- [Greg Cochard](https://github.com/gcochard)
+
+## Resources
+
+- [Chrome Debugging Protocol]
+- [Chrome Debugging Protocol Google group](https://groups.google.com/forum/#!forum/chrome-debugging-protocol)
+- [devtools-protocol official repo](https://github.com/ChromeDevTools/devtools-protocol)
+- [Showcase Chrome Debugging Protocol Clients](https://developer.chrome.com/devtools/docs/debugging-clients)
+- [Awesome chrome-devtools](https://github.com/ChromeDevTools/awesome-chrome-devtools)
+
+[Chrome Debugging Protocol]: https://chromedevtools.github.io/devtools-protocol/

engine/ds-screencast/node_modules/chrome-remote-interface/bin/client.js

@@ -0,0 +1,311 @@
+#!/usr/bin/env node
+
+'use strict';
+
+const repl = require('repl');
+const util = require('util');
+const fs = require('fs');
+const path = require('path');
+
+const program = require('commander');
+
+const CDP = require('../');
+const packageInfo = require('../package.json');
+
+function display(object) {
+    return util.inspect(object, {
+        colors: process.stdout.isTTY,
+        depth: null
+    });
+}
+
+function toJSON(object) {
+    return JSON.stringify(object, null, 4);
+}
+
+///
+
+function inspect(target, args, options) {
+    options.local = args.local;
+    // otherwise the active target
+    if (target) {
+        if (args.webSocket) {
+            // by WebSocket URL
+            options.target = target;
+        } else {
+            // by target id
+            options.target = (targets) => {
+                return targets.findIndex((_target) => {
+                    return _target.id === target;
+                });
+            };
+        }
+    }
+
+    if (args.protocol) {
+        options.protocol = JSON.parse(fs.readFileSync(args.protocol));
+    }
+
+    CDP(options, (client) => {
+        const cdpRepl = repl.start({
+            prompt: process.stdin.isTTY ? '\x1b[32m>>>\x1b[0m ' : '',
+            ignoreUndefined: true,
+            writer: display
+        });
+
+        // XXX always await promises on the REPL
+        const defaultEval = cdpRepl.eval;
+        cdpRepl.eval = (cmd, context, filename, callback) => {
+            defaultEval(cmd, context, filename, async (err, result) => {
+                if (err) {
+                    // propagate errors from the eval
+                    callback(err);
+                } else {
+                    // awaits the promise and either return result or error
+                    try {
+                        callback(null, await Promise.resolve(result));
+                    } catch (err) {
+                        callback(err);
+                    }
+                }
+            });
+        };
+
+        const homePath = process.env.HOME || process.env.USERPROFILE;
+        const historyFile = path.join(homePath, '.cri_history');
+        const historySize = 10000;
+
+        function loadHistory() {
+            // only if run from a terminal
+            if (!process.stdin.isTTY) {
+                return;
+            }
+            // attempt to open the history file
+            let fd;
+            try {
+                fd = fs.openSync(historyFile, 'r');
+            } catch (err) {
+                return; // no history file present
+            }
+            // populate the REPL history
+            fs.readFileSync(fd, 'utf8')
+                .split('\n')
+                .filter((entry) => {
+                    return entry.trim();
+                })
+                .reverse() // to be compatible with repl.history files
+                .forEach((entry) => {
+                    cdpRepl.history.push(entry);
+                });
+        }
+
+        function saveHistory() {
+            // only if run from a terminal
+            if (!process.stdin.isTTY) {
+                return;
+            }
+            // only store the last chunk
+            const entries = cdpRepl.history.slice(0, historySize).reverse().join('\n');
+            fs.writeFileSync(historyFile, entries + '\n');
+        }
+
+        // utility custom command
+        cdpRepl.defineCommand('target', {
+            help: 'Display the current target',
+            action: () => {
+                console.log(client.webSocketUrl);
+                cdpRepl.displayPrompt();
+            }
+        });
+
+        // utility to purge all the event handlers
+        cdpRepl.defineCommand('reset', {
+            help: 'Remove all the registered event handlers',
+            action: () => {
+                client.removeAllListeners();
+                cdpRepl.displayPrompt();
+            }
+        });
+
+        // enable history
+        loadHistory();
+
+        // disconnect on exit
+        cdpRepl.on('exit', () => {
+            if (process.stdin.isTTY) {
+                console.log();
+            }
+            client.close();
+            saveHistory();
+        });
+
+        // exit on disconnection
+        client.on('disconnect', () => {
+            console.error('Disconnected.');
+            saveHistory();
+            process.exit(1);
+        });
+
+        // add protocol API
+        for (const domainObject of client.protocol.domains) {
+            // walk the domain names
+            const domainName = domainObject.domain;
+            cdpRepl.context[domainName] = {};
+            // walk the items in the domain
+            for (const itemName in client[domainName]) {
+                // add CDP object to the REPL context
+                const cdpObject = client[domainName][itemName];
+                cdpRepl.context[domainName][itemName] = cdpObject;
+            }
+        }
+    }).on('error', (err) => {
+        console.error('Cannot connect to remote endpoint:', err.toString());
+    });
+}
+
+function list(options) {
+    CDP.List(options, (err, targets) => {
+        if (err) {
+            console.error(err.toString());
+            process.exit(1);
+        }
+        console.log(toJSON(targets));
+    });
+}
+
+function _new(url, options) {
+    options.url = url;
+    CDP.New(options, (err, target) => {
+        if (err) {
+            console.error(err.toString());
+            process.exit(1);
+        }
+        console.log(toJSON(target));
+    });
+}
+
+function activate(args, options) {
+    options.id = args;
+    CDP.Activate(options, (err) => {
+        if (err) {
+            console.error(err.toString());
+            process.exit(1);
+        }
+    });
+}
+
+function close(args, options) {
+    options.id = args;
+    CDP.Close(options, (err) => {
+        if (err) {
+            console.error(err.toString());
+            process.exit(1);
+        }
+    });
+}
+
+function version(options) {
+    CDP.Version(options, (err, info) => {
+        if (err) {
+            console.error(err.toString());
+            process.exit(1);
+        }
+        console.log(toJSON(info));
+    });
+}
+
+function protocol(args, options) {
+    options.local = args.local;
+    CDP.Protocol(options, (err, protocol) => {
+        if (err) {
+            console.error(err.toString());
+            process.exit(1);
+        }
+        console.log(toJSON(protocol));
+    });
+}
+
+///
+
+let action;
+
+program
+    .option('-v, --v', 'Show this module version')
+    .option('-t, --host <host>', 'HTTP frontend host')
+    .option('-p, --port <port>', 'HTTP frontend port')
+    .option('-s, --secure', 'HTTPS/WSS frontend')
+    .option('-n, --use-host-name', 'Do not perform a DNS lookup of the host');
+
+program
+    .command('inspect [<target>]')
+    .description('inspect a target (defaults to the first available target)')
+    .option('-w, --web-socket', 'interpret <target> as a WebSocket URL instead of a target id')
+    .option('-j, --protocol <file.json>', 'Chrome Debugging Protocol descriptor (overrides `--local`)')
+    .option('-l, --local', 'Use the local protocol descriptor')
+    .action((target, args) => {
+        action = inspect.bind(null, target, args);
+    });
+
+program
+    .command('list')
+    .description('list all the available targets/tabs')
+    .action(() => {
+        action = list;
+    });
+
+program
+    .command('new [<url>]')
+    .description('create a new target/tab')
+    .action((url) => {
+        action = _new.bind(null, url);
+    });
+
+program
+    .command('activate <id>')
+    .description('activate a target/tab by id')
+    .action((id) => {
+        action = activate.bind(null, id);
+    });
+
+program
+    .command('close <id>')
+    .description('close a target/tab by id')
+    .action((id) => {
+        action = close.bind(null, id);
+    });
+
+program
+    .command('version')
+    .description('show the browser version')
+    .action(() => {
+        action = version;
+    });
+
+program
+    .command('protocol')
+    .description('show the currently available protocol descriptor')
+    .option('-l, --local', 'Return the local protocol descriptor')
+    .action((args) => {
+        action = protocol.bind(null, args);
+    });
+
+program.parse(process.argv);
+
+// common options
+const options = {
+    host: program.host,
+    port: program.port,
+    secure: program.secure,
+    useHostName: program.useHostName
+};
+
+if (action) {
+    action(options);
+} else {
+    if (program.v) {
+        console.log(packageInfo.version);
+    } else {
+        program.outputHelp();
+        process.exit(1);
+    }
+}

engine/ds-screencast/node_modules/chrome-remote-interface/index.js

@@ -0,0 +1,46 @@
+'use strict';
+
+const EventEmitter = require('events');
+const dns = require('dns');
+
+const devtools = require('./lib/devtools.js');
+const errors = require('./lib/errors.js');
+const Chrome = require('./lib/chrome.js');
+
+// XXX reset the default that has been changed in
+// (https://github.com/nodejs/node/pull/39987) to prefer IPv4. since
+// implementations alway bind on 127.0.0.1 this solution should be fairly safe
+// (see #467)
+if (dns.setDefaultResultOrder) {
+    dns.setDefaultResultOrder('ipv4first');
+}
+
+function CDP(options, callback) {
+    if (typeof options === 'function') {
+        callback = options;
+        options = undefined;
+    }
+    const notifier = new EventEmitter();
+    if (typeof callback === 'function') {
+        // allow to register the error callback later
+        process.nextTick(() => {
+            new Chrome(options, notifier);
+        });
+        return notifier.once('connect', callback);
+    } else {
+        return new Promise((fulfill, reject) => {
+            notifier.once('connect', fulfill);
+            notifier.once('error', reject);
+            new Chrome(options, notifier);
+        });
+    }
+}
+
+module.exports = CDP;
+module.exports.Protocol = devtools.Protocol;
+module.exports.List = devtools.List;
+module.exports.New = devtools.New;
+module.exports.Activate = devtools.Activate;
+module.exports.Close = devtools.Close;
+module.exports.Version = devtools.Version;
+module.exports.ProtocolError = errors.ProtocolError;

engine/ds-screencast/node_modules/chrome-remote-interface/lib/api.js

@@ -0,0 +1,92 @@
+'use strict';
+
+function arrayToObject(parameters) {
+    const keyValue = {};
+    parameters.forEach((parameter) =>{
+        const name = parameter.name;
+        delete parameter.name;
+        keyValue[name] = parameter;
+    });
+    return keyValue;
+}
+
+function decorate(to, category, object) {
+    to.category = category;
+    Object.keys(object).forEach((field) => {
+        // skip the 'name' field as it is part of the function prototype
+        if (field === 'name') {
+            return;
+        }
+        // commands and events have parameters whereas types have properties
+        if (category === 'type' && field === 'properties' ||
+            field === 'parameters') {
+            to[field] = arrayToObject(object[field]);
+        } else {
+            to[field] = object[field];
+        }
+    });
+}
+
+function addCommand(chrome, domainName, command) {
+    const commandName = `${domainName}.${command.name}`;
+    const handler = (params, sessionId, callback) => {
+        return chrome.send(commandName, params, sessionId, callback);
+    };
+    decorate(handler, 'command', command);
+    chrome[commandName] = chrome[domainName][command.name] = handler;
+}
+
+function addEvent(chrome, domainName, event) {
+    const eventName = `${domainName}.${event.name}`;
+    const handler = (sessionId, handler) => {
+        if (typeof sessionId === 'function') {
+            handler = sessionId;
+            sessionId = undefined;
+        }
+        const rawEventName = sessionId ? `${eventName}.${sessionId}` : eventName;
+        if (typeof handler === 'function') {
+            chrome.on(rawEventName, handler);
+            return () => chrome.removeListener(rawEventName, handler);
+        } else {
+            return new Promise((fulfill, reject) => {
+                chrome.once(rawEventName, fulfill);
+            });
+        }
+    };
+    decorate(handler, 'event', event);
+    chrome[eventName] = chrome[domainName][event.name] = handler;
+}
+
+function addType(chrome, domainName, type) {
+    const typeName = `${domainName}.${type.id}`;
+    const help = {};
+    decorate(help, 'type', type);
+    chrome[typeName] = chrome[domainName][type.id] = help;
+}
+
+function prepare(object, protocol) {
+    // assign the protocol and generate the shorthands
+    object.protocol = protocol;
+    protocol.domains.forEach((domain) => {
+        const domainName = domain.domain;
+        object[domainName] = {};
+        // add commands
+        (domain.commands || []).forEach((command) => {
+            addCommand(object, domainName, command);
+        });
+        // add events
+        (domain.events || []).forEach((event) => {
+            addEvent(object, domainName, event);
+        });
+        // add types
+        (domain.types || []).forEach((type) => {
+            addType(object, domainName, type);
+        });
+        // add utility listener for each domain
+        object[domainName].on = (eventName, handler) => {
+            return object[domainName][eventName](handler);
+        };
+    });
+}
+
+module.exports.prepare = prepare;

engine/ds-screencast/node_modules/chrome-remote-interface/lib/chrome.js

@@ -0,0 +1,302 @@
+'use strict';
+
+const EventEmitter = require('events');
+const util = require('util');
+const formatUrl = require('url').format;
+const parseUrl = require('url').parse;
+
+const WebSocket = require('ws');
+
+const api = require('./api.js');
+const defaults = require('./defaults.js');
+const devtools = require('./devtools.js');
+const errors = require('./errors.js');
+
+class Chrome extends EventEmitter {
+    constructor(options, notifier) {
+        super();
+        // options
+        const defaultTarget = (targets) => {
+            // prefer type = 'page' inspectable targets as they represents
+            // browser tabs (fall back to the first inspectable target
+            // otherwise)
+            let backup;
+            let target = targets.find((target) => {
+                if (target.webSocketDebuggerUrl) {
+                    backup = backup || target;
+                    return target.type === 'page';
+                } else {
+                    return false;
+                }
+            });
+            target = target || backup;
+            if (target) {
+                return target;
+            } else {
+                throw new Error('No inspectable targets');
+            }
+        };
+        options = options || {};
+        this.host = options.host || defaults.HOST;
+        this.port = options.port || defaults.PORT;
+        this.secure = !!(options.secure);
+        this.useHostName = !!(options.useHostName);
+        this.alterPath = options.alterPath || ((path) => path);
+        this.protocol = options.protocol;
+        this.local = !!(options.local);
+        this.target = options.target || defaultTarget;
+        // locals
+        this._notifier = notifier;
+        this._callbacks = {};
+        this._nextCommandId = 1;
+        // properties
+        this.webSocketUrl = undefined;
+        // operations
+        this._start();
+    }
+
+    // avoid misinterpreting protocol's members as custom util.inspect functions
+    inspect(depth, options) {
+        options.customInspect = false;
+        return util.inspect(this, options);
+    }
+
+    send(method, params, sessionId, callback) {
+        // handle optional arguments
+        const optionals = Array.from(arguments).slice(1);
+        params = optionals.find(x => typeof x === 'object');
+        sessionId = optionals.find(x => typeof x === 'string');
+        callback = optionals.find(x => typeof x === 'function');
+        // return a promise when a callback is not provided
+        if (typeof callback === 'function') {
+            this._enqueueCommand(method, params, sessionId, callback);
+            return undefined;
+        } else {
+            return new Promise((fulfill, reject) => {
+                this._enqueueCommand(method, params, sessionId, (error, response) => {
+                    if (error) {
+                        const request = {method, params, sessionId};
+                        reject(
+                            error instanceof Error
+                                ? error // low-level WebSocket error
+                                : new errors.ProtocolError(request, response)
+                        );
+                    } else {
+                        fulfill(response);
+                    }
+                });
+            });
+        }
+    }
+
+    close(callback) {
+        const closeWebSocket = (callback) => {
+            // don't close if it's already closed
+            if (this._ws.readyState === 3) {
+                callback();
+            } else {
+                // don't notify on user-initiated shutdown ('disconnect' event)
+                this._ws.removeAllListeners('close');
+                this._ws.once('close', () => {
+                    this._ws.removeAllListeners();
+                    this._handleConnectionClose();
+                    callback();
+                });
+                this._ws.close();
+            }
+        };
+        if (typeof callback === 'function') {
+            closeWebSocket(callback);
+            return undefined;
+        } else {
+            return new Promise((fulfill, reject) => {
+                closeWebSocket(fulfill);
+            });
+        }
+    }
+
+    // initiate the connection process
+    async _start() {
+        const options = {
+            host: this.host,
+            port: this.port,
+            secure: this.secure,
+            useHostName: this.useHostName,
+            alterPath: this.alterPath
+        };
+        try {
+            // fetch the WebSocket debugger URL
+            const url = await this._fetchDebuggerURL(options);
+            // allow the user to alter the URL
+            const urlObject = parseUrl(url);
+            urlObject.pathname = options.alterPath(urlObject.pathname);
+            this.webSocketUrl = formatUrl(urlObject);
+            // update the connection parameters using the debugging URL
+            options.host = urlObject.hostname;
+            options.port = urlObject.port || options.port;
+            // fetch the protocol and prepare the API
+            const protocol = await this._fetchProtocol(options);
+            api.prepare(this, protocol);
+            // finally connect to the WebSocket
+            await this._connectToWebSocket();
+            // since the handler is executed synchronously, the emit() must be
+            // performed in the next tick so that uncaught errors in the client code
+            // are not intercepted by the Promise mechanism and therefore reported
+            // via the 'error' event
+            process.nextTick(() => {
+                this._notifier.emit('connect', this);
+            });
+        } catch (err) {
+            this._notifier.emit('error', err);
+        }
+    }
+
+    // fetch the WebSocket URL according to 'target'
+    async _fetchDebuggerURL(options) {
+        const userTarget = this.target;
+        switch (typeof userTarget) {
+        case 'string': {
+            let idOrUrl = userTarget;
+            // use default host and port if omitted (and a relative URL is specified)
+            if (idOrUrl.startsWith('/')) {
+                idOrUrl = `ws://${this.host}:${this.port}${idOrUrl}`;
+            }
+            // a WebSocket URL is specified by the user (e.g., node-inspector)
+            if (idOrUrl.match(/^wss?:/i)) {
+                return idOrUrl; // done!
+            }
+            // a target id is specified by the user
+            else {
+                const targets = await devtools.List(options);
+                const object = targets.find((target) => target.id === idOrUrl);
+                return object.webSocketDebuggerUrl;
+            }
+        }
+        case 'object': {
+            const object = userTarget;
+            return object.webSocketDebuggerUrl;
+        }
+        case 'function': {
+            const func = userTarget;
+            const targets = await devtools.List(options);
+            const result = func(targets);
+            const object = typeof result === 'number' ? targets[result] : result;
+            return object.webSocketDebuggerUrl;
+        }
+        default:
+            throw new Error(`Invalid target argument "${this.target}"`);
+        }
+    }
+
+    // fetch the protocol according to 'protocol' and 'local'
+    async _fetchProtocol(options) {
+        // if a protocol has been provided then use it
+        if (this.protocol) {
+            return this.protocol;
+        }
+        // otherwise user either the local or the remote version
+        else {
+            options.local = this.local;
+            return await devtools.Protocol(options);
+        }
+    }
+
+    // establish the WebSocket connection and start processing user commands
+    _connectToWebSocket() {
+        return new Promise((fulfill, reject) => {
+            // create the WebSocket
+            try {
+                if (this.secure) {
+                    this.webSocketUrl = this.webSocketUrl.replace(/^ws:/i, 'wss:');
+                }
+                this._ws = new WebSocket(this.webSocketUrl, [], {
+                    maxPayload: 256 * 1024 * 1024,
+                    perMessageDeflate: false,
+                    followRedirects: true,
+                });
+            } catch (err) {
+                // handles bad URLs
+                reject(err);
+                return;
+            }
+            // set up event handlers
+            this._ws.on('open', () => {
+                fulfill();
+            });
+            this._ws.on('message', (data) => {
+                const message = JSON.parse(data);
+                this._handleMessage(message);
+            });
+            this._ws.on('close', (code) => {
+                this._handleConnectionClose();
+                this.emit('disconnect');
+            });
+            this._ws.on('error', (err) => {
+                reject(err);
+            });
+        });
+    }
+
+    _handleConnectionClose() {
+        // make sure to complete all the unresolved callbacks
+        const err = new Error('WebSocket connection closed');
+        for (const callback of Object.values(this._callbacks)) {
+            callback(err);
+        }
+        this._callbacks = {};
+    }
+
+    // handle the messages read from the WebSocket
+    _handleMessage(message) {
+        // command response
+        if (message.id) {
+            const callback = this._callbacks[message.id];
+            if (!callback) {
+                return;
+            }
+            // interpret the lack of both 'error' and 'result' as success
+            // (this may happen with node-inspector)
+            if (message.error) {
+                callback(true, message.error);
+            } else {
+                callback(false, message.result || {});
+            }
+            // unregister command response callback
+            delete this._callbacks[message.id];
+            // notify when there are no more pending commands
+            if (Object.keys(this._callbacks).length === 0) {
+                this.emit('ready');
+            }
+        }
+        // event
+        else if (message.method) {
+            const {method, params, sessionId} = message;
+            this.emit('event', message);
+            this.emit(method, params, sessionId);
+            this.emit(`${method}.${sessionId}`, params, sessionId);
+        }
+    }
+
+    // send a command to the remote endpoint and register a callback for the reply
+    _enqueueCommand(method, params, sessionId, callback) {
+        const id = this._nextCommandId++;
+        const message = {
+            id,
+            method,
+            sessionId,
+            params: params || {}
+        };
+        this._ws.send(JSON.stringify(message), (err) => {
+            if (err) {
+                // handle low-level WebSocket errors
+                if (typeof callback === 'function') {
+                    callback(err);
+                }
+            } else {
+                this._callbacks[id] = callback;
+            }
+        });
+    }
+}
+
+module.exports = Chrome;

engine/ds-screencast/node_modules/chrome-remote-interface/lib/defaults.js

@@ -0,0 +1,4 @@
+'use strict';
+
+module.exports.HOST = 'localhost';
+module.exports.PORT = 9222;

engine/ds-screencast/node_modules/chrome-remote-interface/lib/devtools.js

@@ -0,0 +1,127 @@
+'use strict';
+
+const http = require('http');
+const https = require('https');
+
+const defaults = require('./defaults.js');
+const externalRequest = require('./external-request.js');
+
+// options.path must be specified; callback(err, data)
+function devToolsInterface(path, options, callback) {
+    const transport = options.secure ? https : http;
+    const requestOptions = {
+        method: options.method,
+        host: options.host || defaults.HOST,
+        port: options.port || defaults.PORT,
+        useHostName: options.useHostName,
+        path: (options.alterPath ? options.alterPath(path) : path)
+    };
+    externalRequest(transport, requestOptions, callback);
+}
+
+// wrapper that allows to return a promise if the callback is omitted, it works
+// for DevTools methods
+function promisesWrapper(func) {
+    return (options, callback) => {
+        // options is an optional argument
+        if (typeof options === 'function') {
+            callback = options;
+            options = undefined;
+        }
+        options = options || {};
+        // just call the function otherwise wrap a promise around its execution
+        if (typeof callback === 'function') {
+            func(options, callback);
+            return undefined;
+        } else {
+            return new Promise((fulfill, reject) => {
+                func(options, (err, result) => {
+                    if (err) {
+                        reject(err);
+                    } else {
+                        fulfill(result);
+                    }
+                });
+            });
+        }
+    };
+}
+
+function Protocol(options, callback) {
+    // if the local protocol is requested
+    if (options.local) {
+        const localDescriptor = require('./protocol.json');
+        callback(null, localDescriptor);
+        return;
+    }
+    // try to fetch the protocol remotely
+    devToolsInterface('/json/protocol', options, (err, descriptor) => {
+        if (err) {
+            callback(err);
+        } else {
+            callback(null, JSON.parse(descriptor));
+        }
+    });
+}
+
+function List(options, callback) {
+    devToolsInterface('/json/list', options, (err, tabs) => {
+        if (err) {
+            callback(err);
+        } else {
+            callback(null, JSON.parse(tabs));
+        }
+    });
+}
+
+function New(options, callback) {
+    let path = '/json/new';
+    if (Object.prototype.hasOwnProperty.call(options, 'url')) {
+        path += `?${options.url}`;
+    }
+    options.method = options.method || 'PUT'; // see #497
+    devToolsInterface(path, options, (err, tab) => {
+        if (err) {
+            callback(err);
+        } else {
+            callback(null, JSON.parse(tab));
+        }
+    });
+}
+
+function Activate(options, callback) {
+    devToolsInterface('/json/activate/' + options.id, options, (err) => {
+        if (err) {
+            callback(err);
+        } else {
+            callback(null);
+        }
+    });
+}
+
+function Close(options, callback) {
+    devToolsInterface('/json/close/' + options.id, options, (err) => {
+        if (err) {
+            callback(err);
+        } else {
+            callback(null);
+        }
+    });
+}
+
+function Version(options, callback) {
+    devToolsInterface('/json/version', options, (err, versionInfo) => {
+        if (err) {
+            callback(err);
+        } else {
+            callback(null, JSON.parse(versionInfo));
+        }
+    });
+}
+
+module.exports.Protocol = promisesWrapper(Protocol);
+module.exports.List = promisesWrapper(List);
+module.exports.New = promisesWrapper(New);
+module.exports.Activate = promisesWrapper(Activate);
+module.exports.Close = promisesWrapper(Close);
+module.exports.Version = promisesWrapper(Version);

engine/ds-screencast/node_modules/chrome-remote-interface/lib/errors.js

@@ -0,0 +1,16 @@
+'use strict';
+
+class ProtocolError extends Error {
+    constructor(request, response) {
+        let {message} = response;
+        if (response.data) {
+            message += ` (${response.data})`;
+        }
+        super(message);
+        // attach the original response as well
+        this.request = request;
+        this.response = response;
+    }
+}
+
+module.exports.ProtocolError = ProtocolError;

engine/ds-screencast/node_modules/chrome-remote-interface/lib/external-request.js

@@ -0,0 +1,44 @@
+'use strict';
+
+const dns = require('dns');
+const util = require('util');
+
+const REQUEST_TIMEOUT = 10000;
+
+// callback(err, data)
+async function externalRequest(transport, options, callback) {
+    // perform the DNS lookup manually so that the HTTP host header generated by
+    // http.get will contain the IP address, this is needed because since Chrome
+    // 66 the host header cannot contain an host name different than localhost
+    // (see https://github.com/cyrus-and/chrome-remote-interface/issues/340)
+    if (!options.useHostName) {
+        try {
+            const {address} = await util.promisify(dns.lookup)(options.host);
+            options.host = address;
+        } catch (err) {
+            callback(err);
+            return;
+        }
+    }
+    // perform the actual request
+    const request = transport.request(options, (response) => {
+        let data = '';
+        response.on('data', (chunk) => {
+            data += chunk;
+        });
+        response.on('end', () => {
+            if (response.statusCode === 200) {
+                callback(null, data);
+            } else {
+                callback(new Error(data));
+            }
+        });
+    });
+    request.setTimeout(REQUEST_TIMEOUT, () => {
+        request.abort();
+    });
+    request.on('error', callback);
+    request.end();
+}
+
+module.exports = externalRequest;

engine/ds-screencast/node_modules/chrome-remote-interface/lib/websocket-wrapper.js

@@ -0,0 +1,39 @@
+'use strict';
+
+const EventEmitter = require('events');
+
+// wrapper around the Node.js ws module
+// for use in browsers
+class WebSocketWrapper extends EventEmitter {
+    constructor(url) {
+        super();
+        this._ws = new WebSocket(url); // eslint-disable-line no-undef
+        this._ws.onopen = () => {
+            this.emit('open');
+        };
+        this._ws.onclose = () => {
+            this.emit('close');
+        };
+        this._ws.onmessage = (event) => {
+            this.emit('message', event.data);
+        };
+        this._ws.onerror = () => {
+            this.emit('error', new Error('WebSocket error'));
+        };
+    }
+
+    close() {
+        this._ws.close();
+    }
+
+    send(data, callback) {
+        try {
+            this._ws.send(data);
+            callback();
+        } catch (err) {
+            callback(err);
+        }
+    }
+}
+
+module.exports = WebSocketWrapper;

engine/ds-screencast/node_modules/chrome-remote-interface/node_modules/ws/LICENSE

@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2011 Einar Otto Stangvik <einaros@gmail.com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

engine/ds-screencast/node_modules/chrome-remote-interface/node_modules/ws/README.md

@@ -0,0 +1,495 @@
+# ws: a Node.js WebSocket library
+
+[![Version npm](https://img.shields.io/npm/v/ws.svg?logo=npm)](https://www.npmjs.com/package/ws)
+[![CI](https://img.shields.io/github/workflow/status/websockets/ws/CI/master?label=CI&logo=github)](https://github.com/websockets/ws/actions?query=workflow%3ACI+branch%3Amaster)
+[![Coverage Status](https://img.shields.io/coveralls/websockets/ws/master.svg?logo=coveralls)](https://coveralls.io/github/websockets/ws)
+
+ws is a simple to use, blazing fast, and thoroughly tested WebSocket client and
+server implementation.
+
+Passes the quite extensive Autobahn test suite: [server][server-report],
+[client][client-report].
+
+**Note**: This module does not work in the browser. The client in the docs is a
+reference to a back end with the role of a client in the WebSocket
+communication. Browser clients must use the native
+[`WebSocket`](https://developer.mozilla.org/en-US/docs/Web/API/WebSocket)
+object. To make the same code work seamlessly on Node.js and the browser, you
+can use one of the many wrappers available on npm, like
+[isomorphic-ws](https://github.com/heineiuo/isomorphic-ws).
+
+## Table of Contents
+
+- [Protocol support](#protocol-support)
+- [Installing](#installing)
+  - [Opt-in for performance](#opt-in-for-performance)
+- [API docs](#api-docs)
+- [WebSocket compression](#websocket-compression)
+- [Usage examples](#usage-examples)
+  - [Sending and receiving text data](#sending-and-receiving-text-data)
+  - [Sending binary data](#sending-binary-data)
+  - [Simple server](#simple-server)
+  - [External HTTP/S server](#external-https-server)
+  - [Multiple servers sharing a single HTTP/S server](#multiple-servers-sharing-a-single-https-server)
+  - [Client authentication](#client-authentication)
+  - [Server broadcast](#server-broadcast)
+  - [echo.websocket.org demo](#echowebsocketorg-demo)
+  - [Use the Node.js streams API](#use-the-nodejs-streams-api)
+  - [Other examples](#other-examples)
+- [FAQ](#faq)
+  - [How to get the IP address of the client?](#how-to-get-the-ip-address-of-the-client)
+  - [How to detect and close broken connections?](#how-to-detect-and-close-broken-connections)
+  - [How to connect via a proxy?](#how-to-connect-via-a-proxy)
+- [Changelog](#changelog)
+- [License](#license)
+
+## Protocol support
+
+- **HyBi drafts 07-12** (Use the option `protocolVersion: 8`)
+- **HyBi drafts 13-17** (Current default, alternatively option
+  `protocolVersion: 13`)
+
+## Installing
+
+```
+npm install ws
+```
+
+### Opt-in for performance
+
+There are 2 optional modules that can be installed along side with the ws
+module. These modules are binary addons which improve certain operations.
+Prebuilt binaries are available for the most popular platforms so you don't
+necessarily need to have a C++ compiler installed on your machine.
+
+- `npm install --save-optional bufferutil`: Allows to efficiently perform
+  operations such as masking and unmasking the data payload of the WebSocket
+  frames.
+- `npm install --save-optional utf-8-validate`: Allows to efficiently check if a
+  message contains valid UTF-8.
+
+## API docs
+
+See [`/doc/ws.md`](./doc/ws.md) for Node.js-like documentation of ws classes and
+utility functions.
+
+## WebSocket compression
+
+ws supports the [permessage-deflate extension][permessage-deflate] which enables
+the client and server to negotiate a compression algorithm and its parameters,
+and then selectively apply it to the data payloads of each WebSocket message.
+
+The extension is disabled by default on the server and enabled by default on the
+client. It adds a significant overhead in terms of performance and memory
+consumption so we suggest to enable it only if it is really needed.
+
+Note that Node.js has a variety of issues with high-performance compression,
+where increased concurrency, especially on Linux, can lead to [catastrophic
+memory fragmentation][node-zlib-bug] and slow performance. If you intend to use
+permessage-deflate in production, it is worthwhile to set up a test
+representative of your workload and ensure Node.js/zlib will handle it with
+acceptable performance and memory usage.
+
+Tuning of permessage-deflate can be done via the options defined below. You can
+also use `zlibDeflateOptions` and `zlibInflateOptions`, which is passed directly
+into the creation of [raw deflate/inflate streams][node-zlib-deflaterawdocs].
+
+See [the docs][ws-server-options] for more options.
+
+```js
+const WebSocket = require('ws');
+
+const wss = new WebSocket.Server({
+  port: 8080,
+  perMessageDeflate: {
+    zlibDeflateOptions: {
+      // See zlib defaults.
+      chunkSize: 1024,
+      memLevel: 7,
+      level: 3
+    },
+    zlibInflateOptions: {
+      chunkSize: 10 * 1024
+    },
+    // Other options settable:
+    clientNoContextTakeover: true, // Defaults to negotiated value.
+    serverNoContextTakeover: true, // Defaults to negotiated value.
+    serverMaxWindowBits: 10, // Defaults to negotiated value.
+    // Below options specified as default values.
+    concurrencyLimit: 10, // Limits zlib concurrency for perf.
+    threshold: 1024 // Size (in bytes) below which messages
+    // should not be compressed.
+  }
+});
+```
+
+The client will only use the extension if it is supported and enabled on the
+server. To always disable the extension on the client set the
+`perMessageDeflate` option to `false`.
+
+```js
+const WebSocket = require('ws');
+
+const ws = new WebSocket('ws://www.host.com/path', {
+  perMessageDeflate: false
+});
+```
+
+## Usage examples
+
+### Sending and receiving text data
+
+```js
+const WebSocket = require('ws');
+
+const ws = new WebSocket('ws://www.host.com/path');
+
+ws.on('open', function open() {
+  ws.send('something');
+});
+
+ws.on('message', function incoming(data) {
+  console.log(data);
+});
+```
+
+### Sending binary data
+
+```js
+const WebSocket = require('ws');
+
+const ws = new WebSocket('ws://www.host.com/path');
+
+ws.on('open', function open() {
+  const array = new Float32Array(5);
+
+  for (var i = 0; i < array.length; ++i) {
+    array[i] = i / 2;
+  }
+
+  ws.send(array);
+});
+```
+
+### Simple server
+
+```js
+const WebSocket = require('ws');
+
+const wss = new WebSocket.Server({ port: 8080 });
+
+wss.on('connection', function connection(ws) {
+  ws.on('message', function incoming(message) {
+    console.log('received: %s', message);
+  });
+
+  ws.send('something');
+});
+```
+
+### External HTTP/S server
+
+```js
+const fs = require('fs');
+const https = require('https');
+const WebSocket = require('ws');
+
+const server = https.createServer({
+  cert: fs.readFileSync('/path/to/cert.pem'),
+  key: fs.readFileSync('/path/to/key.pem')
+});
+const wss = new WebSocket.Server({ server });
+
+wss.on('connection', function connection(ws) {
+  ws.on('message', function incoming(message) {
+    console.log('received: %s', message);
+  });
+
+  ws.send('something');
+});
+
+server.listen(8080);
+```
+
+### Multiple servers sharing a single HTTP/S server
+
+```js
+const http = require('http');
+const WebSocket = require('ws');
+const url = require('url');
+
+const server = http.createServer();
+const wss1 = new WebSocket.Server({ noServer: true });
+const wss2 = new WebSocket.Server({ noServer: true });
+
+wss1.on('connection', function connection(ws) {
+  // ...
+});
+
+wss2.on('connection', function connection(ws) {
+  // ...
+});
+
+server.on('upgrade', function upgrade(request, socket, head) {
+  const pathname = url.parse(request.url).pathname;
+
+  if (pathname === '/foo') {
+    wss1.handleUpgrade(request, socket, head, function done(ws) {
+      wss1.emit('connection', ws, request);
+    });
+  } else if (pathname === '/bar') {
+    wss2.handleUpgrade(request, socket, head, function done(ws) {
+      wss2.emit('connection', ws, request);
+    });
+  } else {
+    socket.destroy();
+  }
+});
+
+server.listen(8080);
+```
+
+### Client authentication
+
+```js
+const http = require('http');
+const WebSocket = require('ws');
+
+const server = http.createServer();
+const wss = new WebSocket.Server({ noServer: true });
+
+wss.on('connection', function connection(ws, request, client) {
+  ws.on('message', function message(msg) {
+    console.log(`Received message ${msg} from user ${client}`);
+  });
+});
+
+server.on('upgrade', function upgrade(request, socket, head) {
+  // This function is not defined on purpose. Implement it with your own logic.
+  authenticate(request, (err, client) => {
+    if (err || !client) {
+      socket.write('HTTP/1.1 401 Unauthorized\r\n\r\n');
+      socket.destroy();
+      return;
+    }
+
+    wss.handleUpgrade(request, socket, head, function done(ws) {
+      wss.emit('connection', ws, request, client);
+    });
+  });
+});
+
+server.listen(8080);
+```
+
+Also see the provided [example][session-parse-example] using `express-session`.
+
+### Server broadcast
+
+A client WebSocket broadcasting to all connected WebSocket clients, including
+itself.
+
+```js
+const WebSocket = require('ws');
+
+const wss = new WebSocket.Server({ port: 8080 });
+
+wss.on('connection', function connection(ws) {
+  ws.on('message', function incoming(data) {
+    wss.clients.forEach(function each(client) {
+      if (client.readyState === WebSocket.OPEN) {
+        client.send(data);
+      }
+    });
+  });
+});
+```
+
+A client WebSocket broadcasting to every other connected WebSocket clients,
+excluding itself.
+
+```js
+const WebSocket = require('ws');
+
+const wss = new WebSocket.Server({ port: 8080 });
+
+wss.on('connection', function connection(ws) {
+  ws.on('message', function incoming(data) {
+    wss.clients.forEach(function each(client) {
+      if (client !== ws && client.readyState === WebSocket.OPEN) {
+        client.send(data);
+      }
+    });
+  });
+});
+```
+
+### echo.websocket.org demo
+
+```js
+const WebSocket = require('ws');
+
+const ws = new WebSocket('wss://echo.websocket.org/', {
+  origin: 'https://websocket.org'
+});
+
+ws.on('open', function open() {
+  console.log('connected');
+  ws.send(Date.now());
+});
+
+ws.on('close', function close() {
+  console.log('disconnected');
+});
+
+ws.on('message', function incoming(data) {
+  console.log(`Roundtrip time: ${Date.now() - data} ms`);
+
+  setTimeout(function timeout() {
+    ws.send(Date.now());
+  }, 500);
+});
+```
+
+### Use the Node.js streams API
+
+```js
+const WebSocket = require('ws');
+
+const ws = new WebSocket('wss://echo.websocket.org/', {
+  origin: 'https://websocket.org'
+});
+
+const duplex = WebSocket.createWebSocketStream(ws, { encoding: 'utf8' });
+
+duplex.pipe(process.stdout);
+process.stdin.pipe(duplex);
+```
+
+### Other examples
+
+For a full example with a browser client communicating with a ws server, see the
+examples folder.
+
+Otherwise, see the test cases.
+
+## FAQ
+
+### How to get the IP address of the client?
+
+The remote IP address can be obtained from the raw socket.
+
+```js
+const WebSocket = require('ws');
+
+const wss = new WebSocket.Server({ port: 8080 });
+
+wss.on('connection', function connection(ws, req) {
+  const ip = req.socket.remoteAddress;
+});
+```
+
+When the server runs behind a proxy like NGINX, the de-facto standard is to use
+the `X-Forwarded-For` header.
+
+```js
+wss.on('connection', function connection(ws, req) {
+  const ip = req.headers['x-forwarded-for'].split(',')[0].trim();
+});
+```
+
+### How to detect and close broken connections?
+
+Sometimes the link between the server and the client can be interrupted in a way
+that keeps both the server and the client unaware of the broken state of the
+connection (e.g. when pulling the cord).
+
+In these cases ping messages can be used as a means to verify that the remote
+endpoint is still responsive.
+
+```js
+const WebSocket = require('ws');
+
+function noop() {}
+
+function heartbeat() {
+  this.isAlive = true;
+}
+
+const wss = new WebSocket.Server({ port: 8080 });
+
+wss.on('connection', function connection(ws) {
+  ws.isAlive = true;
+  ws.on('pong', heartbeat);
+});
+
+const interval = setInterval(function ping() {
+  wss.clients.forEach(function each(ws) {
+    if (ws.isAlive === false) return ws.terminate();
+
+    ws.isAlive = false;
+    ws.ping(noop);
+  });
+}, 30000);
+
+wss.on('close', function close() {
+  clearInterval(interval);
+});
+```
+
+Pong messages are automatically sent in response to ping messages as required by
+the spec.
+
+Just like the server example above your clients might as well lose connection
+without knowing it. You might want to add a ping listener on your clients to
+prevent that. A simple implementation would be:
+
+```js
+const WebSocket = require('ws');
+
+function heartbeat() {
+  clearTimeout(this.pingTimeout);
+
+  // Use `WebSocket#terminate()`, which immediately destroys the connection,
+  // instead of `WebSocket#close()`, which waits for the close timer.
+  // Delay should be equal to the interval at which your server
+  // sends out pings plus a conservative assumption of the latency.
+  this.pingTimeout = setTimeout(() => {
+    this.terminate();
+  }, 30000 + 1000);
+}
+
+const client = new WebSocket('wss://echo.websocket.org/');
+
+client.on('open', heartbeat);
+client.on('ping', heartbeat);
+client.on('close', function clear() {
+  clearTimeout(this.pingTimeout);
+});
+```
+
+### How to connect via a proxy?
+
+Use a custom `http.Agent` implementation like [https-proxy-agent][] or
+[socks-proxy-agent][].
+
+## Changelog
+
+We're using the GitHub [releases][changelog] for changelog entries.
+
+## License
+
+[MIT](LICENSE)
+
+[changelog]: https://github.com/websockets/ws/releases
+[client-report]: http://websockets.github.io/ws/autobahn/clients/
+[https-proxy-agent]: https://github.com/TooTallNate/node-https-proxy-agent
+[node-zlib-bug]: https://github.com/nodejs/node/issues/8871
+[node-zlib-deflaterawdocs]:
+  https://nodejs.org/api/zlib.html#zlib_zlib_createdeflateraw_options
+[permessage-deflate]: https://tools.ietf.org/html/rfc7692
+[server-report]: http://websockets.github.io/ws/autobahn/servers/
+[session-parse-example]: ./examples/express-session-parse
+[socks-proxy-agent]: https://github.com/TooTallNate/node-socks-proxy-agent
+[ws-server-options]:
+  https://github.com/websockets/ws/blob/master/doc/ws.md#new-websocketserveroptions-callback

engine/ds-screencast/node_modules/chrome-remote-interface/node_modules/ws/browser.js

@@ -0,0 +1,8 @@
+'use strict';
+
+module.exports = function () {
+  throw new Error(
+    'ws does not work in the browser. Browser clients must use the native ' +
+      'WebSocket object'
+  );
+};

engine/ds-screencast/node_modules/chrome-remote-interface/node_modules/ws/index.js

@@ -0,0 +1,10 @@
+'use strict';
+
+const WebSocket = require('./lib/websocket');
+
+WebSocket.createWebSocketStream = require('./lib/stream');
+WebSocket.Server = require('./lib/websocket-server');
+WebSocket.Receiver = require('./lib/receiver');
+WebSocket.Sender = require('./lib/sender');
+
+module.exports = WebSocket;

engine/ds-screencast/node_modules/chrome-remote-interface/node_modules/ws/lib/buffer-util.js

@@ -0,0 +1,129 @@
+'use strict';
+
+const { EMPTY_BUFFER } = require('./constants');
+
+/**
+ * Merges an array of buffers into a new buffer.
+ *
+ * @param {Buffer[]} list The array of buffers to concat
+ * @param {Number} totalLength The total length of buffers in the list
+ * @return {Buffer} The resulting buffer
+ * @public
+ */
+function concat(list, totalLength) {
+  if (list.length === 0) return EMPTY_BUFFER;
+  if (list.length === 1) return list[0];
+
+  const target = Buffer.allocUnsafe(totalLength);
+  let offset = 0;
+
+  for (let i = 0; i < list.length; i++) {
+    const buf = list[i];
+    target.set(buf, offset);
+    offset += buf.length;
+  }
+
+  if (offset < totalLength) return target.slice(0, offset);
+
+  return target;
+}
+
+/**
+ * Masks a buffer using the given mask.
+ *
+ * @param {Buffer} source The buffer to mask
+ * @param {Buffer} mask The mask to use
+ * @param {Buffer} output The buffer where to store the result
+ * @param {Number} offset The offset at which to start writing
+ * @param {Number} length The number of bytes to mask.
+ * @public
+ */
+function _mask(source, mask, output, offset, length) {
+  for (let i = 0; i < length; i++) {
+    output[offset + i] = source[i] ^ mask[i & 3];
+  }
+}
+
+/**
+ * Unmasks a buffer using the given mask.
+ *
+ * @param {Buffer} buffer The buffer to unmask
+ * @param {Buffer} mask The mask to use
+ * @public
+ */
+function _unmask(buffer, mask) {
+  // Required until https://github.com/nodejs/node/issues/9006 is resolved.
+  const length = buffer.length;
+  for (let i = 0; i < length; i++) {
+    buffer[i] ^= mask[i & 3];
+  }
+}
+
+/**
+ * Converts a buffer to an `ArrayBuffer`.
+ *
+ * @param {Buffer} buf The buffer to convert
+ * @return {ArrayBuffer} Converted buffer
+ * @public
+ */
+function toArrayBuffer(buf) {
+  if (buf.byteLength === buf.buffer.byteLength) {
+    return buf.buffer;
+  }
+
+  return buf.buffer.slice(buf.byteOffset, buf.byteOffset + buf.byteLength);
+}
+
+/**
+ * Converts `data` to a `Buffer`.
+ *
+ * @param {*} data The data to convert
+ * @return {Buffer} The buffer
+ * @throws {TypeError}
+ * @public
+ */
+function toBuffer(data) {
+  toBuffer.readOnly = true;
+
+  if (Buffer.isBuffer(data)) return data;
+
+  let buf;
+
+  if (data instanceof ArrayBuffer) {
+    buf = Buffer.from(data);
+  } else if (ArrayBuffer.isView(data)) {
+    buf = Buffer.from(data.buffer, data.byteOffset, data.byteLength);
+  } else {
+    buf = Buffer.from(data);
+    toBuffer.readOnly = false;
+  }
+
+  return buf;
+}
+
+try {
+  const bufferUtil = require('bufferutil');
+  const bu = bufferUtil.BufferUtil || bufferUtil;
+
+  module.exports = {
+    concat,
+    mask(source, mask, output, offset, length) {
+      if (length < 48) _mask(source, mask, output, offset, length);
+      else bu.mask(source, mask, output, offset, length);
+    },
+    toArrayBuffer,
+    toBuffer,
+    unmask(buffer, mask) {
+      if (buffer.length < 32) _unmask(buffer, mask);
+      else bu.unmask(buffer, mask);
+    }
+  };
+} catch (e) /* istanbul ignore next */ {
+  module.exports = {
+    concat,
+    mask: _mask,
+    toArrayBuffer,
+    toBuffer,
+    unmask: _unmask
+  };
+}

engine/ds-screencast/node_modules/chrome-remote-interface/node_modules/ws/lib/constants.js

@@ -0,0 +1,10 @@
+'use strict';
+
+module.exports = {
+  BINARY_TYPES: ['nodebuffer', 'arraybuffer', 'fragments'],
+  GUID: '258EAFA5-E914-47DA-95CA-C5AB0DC85B11',
+  kStatusCode: Symbol('status-code'),
+  kWebSocket: Symbol('websocket'),
+  EMPTY_BUFFER: Buffer.alloc(0),
+  NOOP: () => {}
+};

engine/ds-screencast/node_modules/chrome-remote-interface/node_modules/ws/lib/event-target.js

@@ -0,0 +1,184 @@
+'use strict';
+
+/**
+ * Class representing an event.
+ *
+ * @private
+ */
+class Event {
+  /**
+   * Create a new `Event`.
+   *
+   * @param {String} type The name of the event
+   * @param {Object} target A reference to the target to which the event was
+   *     dispatched
+   */
+  constructor(type, target) {
+    this.target = target;
+    this.type = type;
+  }
+}
+
+/**
+ * Class representing a message event.
+ *
+ * @extends Event
+ * @private
+ */
+class MessageEvent extends Event {
+  /**
+   * Create a new `MessageEvent`.
+   *
+   * @param {(String|Buffer|ArrayBuffer|Buffer[])} data The received data
+   * @param {WebSocket} target A reference to the target to which the event was
+   *     dispatched
+   */
+  constructor(data, target) {
+    super('message', target);
+
+    this.data = data;
+  }
+}
+
+/**
+ * Class representing a close event.
+ *
+ * @extends Event
+ * @private
+ */
+class CloseEvent extends Event {
+  /**
+   * Create a new `CloseEvent`.
+   *
+   * @param {Number} code The status code explaining why the connection is being
+   *     closed
+   * @param {String} reason A human-readable string explaining why the
+   *     connection is closing
+   * @param {WebSocket} target A reference to the target to which the event was
+   *     dispatched
+   */
+  constructor(code, reason, target) {
+    super('close', target);
+
+    this.wasClean = target._closeFrameReceived && target._closeFrameSent;
+    this.reason = reason;
+    this.code = code;
+  }
+}
+
+/**
+ * Class representing an open event.
+ *
+ * @extends Event
+ * @private
+ */
+class OpenEvent extends Event {
+  /**
+   * Create a new `OpenEvent`.
+   *
+   * @param {WebSocket} target A reference to the target to which the event was
+   *     dispatched
+   */
+  constructor(target) {
+    super('open', target);
+  }
+}
+
+/**
+ * Class representing an error event.
+ *
+ * @extends Event
+ * @private
+ */
+class ErrorEvent extends Event {
+  /**
+   * Create a new `ErrorEvent`.
+   *
+   * @param {Object} error The error that generated this event
+   * @param {WebSocket} target A reference to the target to which the event was
+   *     dispatched
+   */
+  constructor(error, target) {
+    super('error', target);
+
+    this.message = error.message;
+    this.error = error;
+  }
+}
+
+/**
+ * This provides methods for emulating the `EventTarget` interface. It's not
+ * meant to be used directly.
+ *
+ * @mixin
+ */
+const EventTarget = {
+  /**
+   * Register an event listener.
+   *
+   * @param {String} type A string representing the event type to listen for
+   * @param {Function} listener The listener to add
+   * @param {Object} [options] An options object specifies characteristics about
+   *     the event listener
+   * @param {Boolean} [options.once=false] A `Boolean`` indicating that the
+   *     listener should be invoked at most once after being added. If `true`,
+   *     the listener would be automatically removed when invoked.
+   * @public
+   */
+  addEventListener(type, listener, options) {
+    if (typeof listener !== 'function') return;
+
+    function onMessage(data) {
+      listener.call(this, new MessageEvent(data, this));
+    }
+
+    function onClose(code, message) {
+      listener.call(this, new CloseEvent(code, message, this));
+    }
+
+    function onError(error) {
+      listener.call(this, new ErrorEvent(error, this));
+    }
+
+    function onOpen() {
+      listener.call(this, new OpenEvent(this));
+    }
+
+    const method = options && options.once ? 'once' : 'on';
+
+    if (type === 'message') {
+      onMessage._listener = listener;
+      this[method](type, onMessage);
+    } else if (type === 'close') {
+      onClose._listener = listener;
+      this[method](type, onClose);
+    } else if (type === 'error') {
+      onError._listener = listener;
+      this[method](type, onError);
+    } else if (type === 'open') {
+      onOpen._listener = listener;
+      this[method](type, onOpen);
+    } else {
+      this[method](type, listener);
+    }
+  },
+
+  /**
+   * Remove an event listener.
+   *
+   * @param {String} type A string representing the event type to remove
+   * @param {Function} listener The listener to remove
+   * @public
+   */
+  removeEventListener(type, listener) {
+    const listeners = this.listeners(type);
+
+    for (let i = 0; i < listeners.length; i++) {
+      if (listeners[i] === listener || listeners[i]._listener === listener) {
+        this.removeListener(type, listeners[i]);
+      }
+    }
+  }
+};
+
+module.exports = EventTarget;

engine/ds-screencast/node_modules/chrome-remote-interface/node_modules/ws/lib/extension.js

@@ -0,0 +1,223 @@
+'use strict';
+
+//
+// Allowed token characters:
+//
+// '!', '#', '$', '%', '&', ''', '*', '+', '-',
+// '.', 0-9, A-Z, '^', '_', '`', a-z, '|', '~'
+//
+// tokenChars[32] === 0 // ' '
+// tokenChars[33] === 1 // '!'
+// tokenChars[34] === 0 // '"'
+// ...
+//
+// prettier-ignore
+const tokenChars = [
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 0 - 15
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 16 - 31
+  0, 1, 0, 1, 1, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 0, // 32 - 47
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, // 48 - 63
+  0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 64 - 79
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, // 80 - 95
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 96 - 111
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0 // 112 - 127
+];
+
+/**
+ * Adds an offer to the map of extension offers or a parameter to the map of
+ * parameters.
+ *
+ * @param {Object} dest The map of extension offers or parameters
+ * @param {String} name The extension or parameter name
+ * @param {(Object|Boolean|String)} elem The extension parameters or the
+ *     parameter value
+ * @private
+ */
+function push(dest, name, elem) {
+  if (dest[name] === undefined) dest[name] = [elem];
+  else dest[name].push(elem);
+}
+
+/**
+ * Parses the `Sec-WebSocket-Extensions` header into an object.
+ *
+ * @param {String} header The field value of the header
+ * @return {Object} The parsed object
+ * @public
+ */
+function parse(header) {
+  const offers = Object.create(null);
+
+  if (header === undefined || header === '') return offers;
+
+  let params = Object.create(null);
+  let mustUnescape = false;
+  let isEscaping = false;
+  let inQuotes = false;
+  let extensionName;
+  let paramName;
+  let start = -1;
+  let end = -1;
+  let i = 0;
+
+  for (; i < header.length; i++) {
+    const code = header.charCodeAt(i);
+
+    if (extensionName === undefined) {
+      if (end === -1 && tokenChars[code] === 1) {
+        if (start === -1) start = i;
+      } else if (code === 0x20 /* ' ' */ || code === 0x09 /* '\t' */) {
+        if (end === -1 && start !== -1) end = i;
+      } else if (code === 0x3b /* ';' */ || code === 0x2c /* ',' */) {
+        if (start === -1) {
+          throw new SyntaxError(`Unexpected character at index ${i}`);
+        }
+
+        if (end === -1) end = i;
+        const name = header.slice(start, end);
+        if (code === 0x2c) {
+          push(offers, name, params);
+          params = Object.create(null);
+        } else {
+          extensionName = name;
+        }
+
+        start = end = -1;
+      } else {
+        throw new SyntaxError(`Unexpected character at index ${i}`);
+      }
+    } else if (paramName === undefined) {
+      if (end === -1 && tokenChars[code] === 1) {
+        if (start === -1) start = i;
+      } else if (code === 0x20 || code === 0x09) {
+        if (end === -1 && start !== -1) end = i;
+      } else if (code === 0x3b || code === 0x2c) {
+        if (start === -1) {
+          throw new SyntaxError(`Unexpected character at index ${i}`);
+        }
+
+        if (end === -1) end = i;
+        push(params, header.slice(start, end), true);
+        if (code === 0x2c) {
+          push(offers, extensionName, params);
+          params = Object.create(null);
+          extensionName = undefined;
+        }
+
+        start = end = -1;
+      } else if (code === 0x3d /* '=' */ && start !== -1 && end === -1) {
+        paramName = header.slice(start, i);
+        start = end = -1;
+      } else {
+        throw new SyntaxError(`Unexpected character at index ${i}`);
+      }
+    } else {
+      //
+      // The value of a quoted-string after unescaping must conform to the
+      // token ABNF, so only token characters are valid.
+      // Ref: https://tools.ietf.org/html/rfc6455#section-9.1
+      //
+      if (isEscaping) {
+        if (tokenChars[code] !== 1) {
+          throw new SyntaxError(`Unexpected character at index ${i}`);
+        }
+        if (start === -1) start = i;
+        else if (!mustUnescape) mustUnescape = true;
+        isEscaping = false;
+      } else if (inQuotes) {
+        if (tokenChars[code] === 1) {
+          if (start === -1) start = i;
+        } else if (code === 0x22 /* '"' */ && start !== -1) {
+          inQuotes = false;
+          end = i;
+        } else if (code === 0x5c /* '\' */) {
+          isEscaping = true;
+        } else {
+          throw new SyntaxError(`Unexpected character at index ${i}`);
+        }
+      } else if (code === 0x22 && header.charCodeAt(i - 1) === 0x3d) {
+        inQuotes = true;
+      } else if (end === -1 && tokenChars[code] === 1) {
+        if (start === -1) start = i;
+      } else if (start !== -1 && (code === 0x20 || code === 0x09)) {
+        if (end === -1) end = i;
+      } else if (code === 0x3b || code === 0x2c) {
+        if (start === -1) {
+          throw new SyntaxError(`Unexpected character at index ${i}`);
+        }
+
+        if (end === -1) end = i;
+        let value = header.slice(start, end);
+        if (mustUnescape) {
+          value = value.replace(/\\/g, '');
+          mustUnescape = false;
+        }
+        push(params, paramName, value);
+        if (code === 0x2c) {
+          push(offers, extensionName, params);
+          params = Object.create(null);
+          extensionName = undefined;
+        }
+
+        paramName = undefined;
+        start = end = -1;
+      } else {
+        throw new SyntaxError(`Unexpected character at index ${i}`);
+      }
+    }
+  }
+
+  if (start === -1 || inQuotes) {
+    throw new SyntaxError('Unexpected end of input');
+  }
+
+  if (end === -1) end = i;
+  const token = header.slice(start, end);
+  if (extensionName === undefined) {
+    push(offers, token, params);
+  } else {
+    if (paramName === undefined) {
+      push(params, token, true);
+    } else if (mustUnescape) {
+      push(params, paramName, token.replace(/\\/g, ''));
+    } else {
+      push(params, paramName, token);
+    }
+    push(offers, extensionName, params);
+  }
+
+  return offers;
+}
+
+/**
+ * Builds the `Sec-WebSocket-Extensions` header field value.
+ *
+ * @param {Object} extensions The map of extensions and parameters to format
+ * @return {String} A string representing the given object
+ * @public
+ */
+function format(extensions) {
+  return Object.keys(extensions)
+    .map((extension) => {
+      let configurations = extensions[extension];
+      if (!Array.isArray(configurations)) configurations = [configurations];
+      return configurations
+        .map((params) => {
+          return [extension]
+            .concat(
+              Object.keys(params).map((k) => {
+                let values = params[k];
+                if (!Array.isArray(values)) values = [values];
+                return values
+                  .map((v) => (v === true ? k : `${k}=${v}`))
+                  .join('; ');
+              })
+            )
+            .join('; ');
+        })
+        .join(', ');
+    })
+    .join(', ');
+}
+
+module.exports = { format, parse };

engine/ds-screencast/node_modules/chrome-remote-interface/node_modules/ws/lib/limiter.js

@@ -0,0 +1,55 @@
+'use strict';
+
+const kDone = Symbol('kDone');
+const kRun = Symbol('kRun');
+
+/**
+ * A very simple job queue with adjustable concurrency. Adapted from
+ * https://github.com/STRML/async-limiter
+ */
+class Limiter {
+  /**
+   * Creates a new `Limiter`.
+   *
+   * @param {Number} [concurrency=Infinity] The maximum number of jobs allowed
+   *     to run concurrently
+   */
+  constructor(concurrency) {
+    this[kDone] = () => {
+      this.pending--;
+      this[kRun]();
+    };
+    this.concurrency = concurrency || Infinity;
+    this.jobs = [];
+    this.pending = 0;
+  }
+
+  /**
+   * Adds a job to the queue.
+   *
+   * @param {Function} job The job to run
+   * @public
+   */
+  add(job) {
+    this.jobs.push(job);
+    this[kRun]();
+  }
+
+  /**
+   * Removes a job from the queue and runs it if possible.
+   *
+   * @private
+   */
+  [kRun]() {
+    if (this.pending === this.concurrency) return;
+
+    if (this.jobs.length) {
+      const job = this.jobs.shift();
+
+      this.pending++;
+      job(this[kDone]);
+    }
+  }
+}
+
+module.exports = Limiter;

engine/ds-screencast/node_modules/chrome-remote-interface/node_modules/ws/lib/permessage-deflate.js

@@ -0,0 +1,518 @@
+'use strict';
+
+const zlib = require('zlib');
+
+const bufferUtil = require('./buffer-util');
+const Limiter = require('./limiter');
+const { kStatusCode, NOOP } = require('./constants');
+
+const TRAILER = Buffer.from([0x00, 0x00, 0xff, 0xff]);
+const kPerMessageDeflate = Symbol('permessage-deflate');
+const kTotalLength = Symbol('total-length');
+const kCallback = Symbol('callback');
+const kBuffers = Symbol('buffers');
+const kError = Symbol('error');
+
+//
+// We limit zlib concurrency, which prevents severe memory fragmentation
+// as documented in https://github.com/nodejs/node/issues/8871#issuecomment-250915913
+// and https://github.com/websockets/ws/issues/1202
+//
+// Intentionally global; it's the global thread pool that's an issue.
+//
+let zlibLimiter;
+
+/**
+ * permessage-deflate implementation.
+ */
+class PerMessageDeflate {
+  /**
+   * Creates a PerMessageDeflate instance.
+   *
+   * @param {Object} [options] Configuration options
+   * @param {Boolean} [options.serverNoContextTakeover=false] Request/accept
+   *     disabling of server context takeover
+   * @param {Boolean} [options.clientNoContextTakeover=false] Advertise/
+   *     acknowledge disabling of client context takeover
+   * @param {(Boolean|Number)} [options.serverMaxWindowBits] Request/confirm the
+   *     use of a custom server window size
+   * @param {(Boolean|Number)} [options.clientMaxWindowBits] Advertise support
+   *     for, or request, a custom client window size
+   * @param {Object} [options.zlibDeflateOptions] Options to pass to zlib on
+   *     deflate
+   * @param {Object} [options.zlibInflateOptions] Options to pass to zlib on
+   *     inflate
+   * @param {Number} [options.threshold=1024] Size (in bytes) below which
+   *     messages should not be compressed
+   * @param {Number} [options.concurrencyLimit=10] The number of concurrent
+   *     calls to zlib
+   * @param {Boolean} [isServer=false] Create the instance in either server or
+   *     client mode
+   * @param {Number} [maxPayload=0] The maximum allowed message length
+   */
+  constructor(options, isServer, maxPayload) {
+    this._maxPayload = maxPayload | 0;
+    this._options = options || {};
+    this._threshold =
+      this._options.threshold !== undefined ? this._options.threshold : 1024;
+    this._isServer = !!isServer;
+    this._deflate = null;
+    this._inflate = null;
+
+    this.params = null;
+
+    if (!zlibLimiter) {
+      const concurrency =
+        this._options.concurrencyLimit !== undefined
+          ? this._options.concurrencyLimit
+          : 10;
+      zlibLimiter = new Limiter(concurrency);
+    }
+  }
+
+  /**
+   * @type {String}
+   */
+  static get extensionName() {
+    return 'permessage-deflate';
+  }
+
+  /**
+   * Create an extension negotiation offer.
+   *
+   * @return {Object} Extension parameters
+   * @public
+   */
+  offer() {
+    const params = {};
+
+    if (this._options.serverNoContextTakeover) {
+      params.server_no_context_takeover = true;
+    }
+    if (this._options.clientNoContextTakeover) {
+      params.client_no_context_takeover = true;
+    }
+    if (this._options.serverMaxWindowBits) {
+      params.server_max_window_bits = this._options.serverMaxWindowBits;
+    }
+    if (this._options.clientMaxWindowBits) {
+      params.client_max_window_bits = this._options.clientMaxWindowBits;
+    } else if (this._options.clientMaxWindowBits == null) {
+      params.client_max_window_bits = true;
+    }
+
+    return params;
+  }
+
+  /**
+   * Accept an extension negotiation offer/response.
+   *
+   * @param {Array} configurations The extension negotiation offers/reponse
+   * @return {Object} Accepted configuration
+   * @public
+   */
+  accept(configurations) {
+    configurations = this.normalizeParams(configurations);
+
+    this.params = this._isServer
+      ? this.acceptAsServer(configurations)
+      : this.acceptAsClient(configurations);
+
+    return this.params;
+  }
+
+  /**
+   * Releases all resources used by the extension.
+   *
+   * @public
+   */
+  cleanup() {
+    if (this._inflate) {
+      this._inflate.close();
+      this._inflate = null;
+    }
+
+    if (this._deflate) {
+      const callback = this._deflate[kCallback];
+
+      this._deflate.close();
+      this._deflate = null;
+
+      if (callback) {
+        callback(
+          new Error(
+            'The deflate stream was closed while data was being processed'
+          )
+        );
+      }
+    }
+  }
+
+  /**
+   *  Accept an extension negotiation offer.
+   *
+   * @param {Array} offers The extension negotiation offers
+   * @return {Object} Accepted configuration
+   * @private
+   */
+  acceptAsServer(offers) {
+    const opts = this._options;
+    const accepted = offers.find((params) => {
+      if (
+        (opts.serverNoContextTakeover === false &&
+          params.server_no_context_takeover) ||
+        (params.server_max_window_bits &&
+          (opts.serverMaxWindowBits === false ||
+            (typeof opts.serverMaxWindowBits === 'number' &&
+              opts.serverMaxWindowBits > params.server_max_window_bits))) ||
+        (typeof opts.clientMaxWindowBits === 'number' &&
+          !params.client_max_window_bits)
+      ) {
+        return false;
+      }
+
+      return true;
+    });
+
+    if (!accepted) {
+      throw new Error('None of the extension offers can be accepted');
+    }
+
+    if (opts.serverNoContextTakeover) {
+      accepted.server_no_context_takeover = true;
+    }
+    if (opts.clientNoContextTakeover) {
+      accepted.client_no_context_takeover = true;
+    }
+    if (typeof opts.serverMaxWindowBits === 'number') {
+      accepted.server_max_window_bits = opts.serverMaxWindowBits;
+    }
+    if (typeof opts.clientMaxWindowBits === 'number') {
+      accepted.client_max_window_bits = opts.clientMaxWindowBits;
+    } else if (
+      accepted.client_max_window_bits === true ||
+      opts.clientMaxWindowBits === false
+    ) {
+      delete accepted.client_max_window_bits;
+    }
+
+    return accepted;
+  }
+
+  /**
+   * Accept the extension negotiation response.
+   *
+   * @param {Array} response The extension negotiation response
+   * @return {Object} Accepted configuration
+   * @private
+   */
+  acceptAsClient(response) {
+    const params = response[0];
+
+    if (
+      this._options.clientNoContextTakeover === false &&
+      params.client_no_context_takeover
+    ) {
+      throw new Error('Unexpected parameter "client_no_context_takeover"');
+    }
+
+    if (!params.client_max_window_bits) {
+      if (typeof this._options.clientMaxWindowBits === 'number') {
+        params.client_max_window_bits = this._options.clientMaxWindowBits;
+      }
+    } else if (
+      this._options.clientMaxWindowBits === false ||
+      (typeof this._options.clientMaxWindowBits === 'number' &&
+        params.client_max_window_bits > this._options.clientMaxWindowBits)
+    ) {
+      throw new Error(
+        'Unexpected or invalid parameter "client_max_window_bits"'
+      );
+    }
+
+    return params;
+  }
+
+  /**
+   * Normalize parameters.
+   *
+   * @param {Array} configurations The extension negotiation offers/reponse
+   * @return {Array} The offers/response with normalized parameters
+   * @private
+   */
+  normalizeParams(configurations) {
+    configurations.forEach((params) => {
+      Object.keys(params).forEach((key) => {
+        let value = params[key];
+
+        if (value.length > 1) {
+          throw new Error(`Parameter "${key}" must have only a single value`);
+        }
+
+        value = value[0];
+
+        if (key === 'client_max_window_bits') {
+          if (value !== true) {
+            const num = +value;
+            if (!Number.isInteger(num) || num < 8 || num > 15) {
+              throw new TypeError(
+                `Invalid value for parameter "${key}": ${value}`
+              );
+            }
+            value = num;
+          } else if (!this._isServer) {
+            throw new TypeError(
+              `Invalid value for parameter "${key}": ${value}`
+            );
+          }
+        } else if (key === 'server_max_window_bits') {
+          const num = +value;
+          if (!Number.isInteger(num) || num < 8 || num > 15) {
+            throw new TypeError(
+              `Invalid value for parameter "${key}": ${value}`
+            );
+          }
+          value = num;
+        } else if (
+          key === 'client_no_context_takeover' ||
+          key === 'server_no_context_takeover'
+        ) {
+          if (value !== true) {
+            throw new TypeError(
+              `Invalid value for parameter "${key}": ${value}`
+            );
+          }
+        } else {
+          throw new Error(`Unknown parameter "${key}"`);
+        }
+
+        params[key] = value;
+      });
+    });
+
+    return configurations;
+  }
+
+  /**
+   * Decompress data. Concurrency limited.
+   *
+   * @param {Buffer} data Compressed data
+   * @param {Boolean} fin Specifies whether or not this is the last fragment
+   * @param {Function} callback Callback
+   * @public
+   */
+  decompress(data, fin, callback) {
+    zlibLimiter.add((done) => {
+      this._decompress(data, fin, (err, result) => {
+        done();
+        callback(err, result);
+      });
+    });
+  }
+
+  /**
+   * Compress data. Concurrency limited.
+   *
+   * @param {Buffer} data Data to compress
+   * @param {Boolean} fin Specifies whether or not this is the last fragment
+   * @param {Function} callback Callback
+   * @public
+   */
+  compress(data, fin, callback) {
+    zlibLimiter.add((done) => {
+      this._compress(data, fin, (err, result) => {
+        done();
+        callback(err, result);
+      });
+    });
+  }
+
+  /**
+   * Decompress data.
+   *
+   * @param {Buffer} data Compressed data
+   * @param {Boolean} fin Specifies whether or not this is the last fragment
+   * @param {Function} callback Callback
+   * @private
+   */
+  _decompress(data, fin, callback) {
+    const endpoint = this._isServer ? 'client' : 'server';
+
+    if (!this._inflate) {
+      const key = `${endpoint}_max_window_bits`;
+      const windowBits =
+        typeof this.params[key] !== 'number'
+          ? zlib.Z_DEFAULT_WINDOWBITS
+          : this.params[key];
+
+      this._inflate = zlib.createInflateRaw({
+        ...this._options.zlibInflateOptions,
+        windowBits
+      });
+      this._inflate[kPerMessageDeflate] = this;
+      this._inflate[kTotalLength] = 0;
+      this._inflate[kBuffers] = [];
+      this._inflate.on('error', inflateOnError);
+      this._inflate.on('data', inflateOnData);
+    }
+
+    this._inflate[kCallback] = callback;
+
+    this._inflate.write(data);
+    if (fin) this._inflate.write(TRAILER);
+
+    this._inflate.flush(() => {
+      const err = this._inflate[kError];
+
+      if (err) {
+        this._inflate.close();
+        this._inflate = null;
+        callback(err);
+        return;
+      }
+
+      const data = bufferUtil.concat(
+        this._inflate[kBuffers],
+        this._inflate[kTotalLength]
+      );
+
+      if (this._inflate._readableState.endEmitted) {
+        this._inflate.close();
+        this._inflate = null;
+      } else {
+        this._inflate[kTotalLength] = 0;
+        this._inflate[kBuffers] = [];
+
+        if (fin && this.params[`${endpoint}_no_context_takeover`]) {
+          this._inflate.reset();
+        }
+      }
+
+      callback(null, data);
+    });
+  }
+
+  /**
+   * Compress data.
+   *
+   * @param {Buffer} data Data to compress
+   * @param {Boolean} fin Specifies whether or not this is the last fragment
+   * @param {Function} callback Callback
+   * @private
+   */
+  _compress(data, fin, callback) {
+    const endpoint = this._isServer ? 'server' : 'client';
+
+    if (!this._deflate) {
+      const key = `${endpoint}_max_window_bits`;
+      const windowBits =
+        typeof this.params[key] !== 'number'
+          ? zlib.Z_DEFAULT_WINDOWBITS
+          : this.params[key];
+
+      this._deflate = zlib.createDeflateRaw({
+        ...this._options.zlibDeflateOptions,
+        windowBits
+      });
+
+      this._deflate[kTotalLength] = 0;
+      this._deflate[kBuffers] = [];
+
+      //
+      // An `'error'` event is emitted, only on Node.js < 10.0.0, if the
+      // `zlib.DeflateRaw` instance is closed while data is being processed.
+      // This can happen if `PerMessageDeflate#cleanup()` is called at the wrong
+      // time due to an abnormal WebSocket closure.
+      //
+      this._deflate.on('error', NOOP);
+      this._deflate.on('data', deflateOnData);
+    }
+
+    this._deflate[kCallback] = callback;
+
+    this._deflate.write(data);
+    this._deflate.flush(zlib.Z_SYNC_FLUSH, () => {
+      if (!this._deflate) {
+        //
+        // The deflate stream was closed while data was being processed.
+        //
+        return;
+      }
+
+      let data = bufferUtil.concat(
+        this._deflate[kBuffers],
+        this._deflate[kTotalLength]
+      );
+
+      if (fin) data = data.slice(0, data.length - 4);
+
+      //
+      // Ensure that the callback will not be called again in
+      // `PerMessageDeflate#cleanup()`.
+      //
+      this._deflate[kCallback] = null;
+
+      this._deflate[kTotalLength] = 0;
+      this._deflate[kBuffers] = [];
+
+      if (fin && this.params[`${endpoint}_no_context_takeover`]) {
+        this._deflate.reset();
+      }
+
+      callback(null, data);
+    });
+  }
+}
+
+module.exports = PerMessageDeflate;
+
+/**
+ * The listener of the `zlib.DeflateRaw` stream `'data'` event.
+ *
+ * @param {Buffer} chunk A chunk of data
+ * @private
+ */
+function deflateOnData(chunk) {
+  this[kBuffers].push(chunk);
+  this[kTotalLength] += chunk.length;
+}
+
+/**
+ * The listener of the `zlib.InflateRaw` stream `'data'` event.
+ *
+ * @param {Buffer} chunk A chunk of data
+ * @private
+ */
+function inflateOnData(chunk) {
+  this[kTotalLength] += chunk.length;
+
+  if (
+    this[kPerMessageDeflate]._maxPayload < 1 ||
+    this[kTotalLength] <= this[kPerMessageDeflate]._maxPayload
+  ) {
+    this[kBuffers].push(chunk);
+    return;
+  }
+
+  this[kError] = new RangeError('Max payload size exceeded');
+  this[kError].code = 'WS_ERR_UNSUPPORTED_MESSAGE_LENGTH';
+  this[kError][kStatusCode] = 1009;
+  this.removeListener('data', inflateOnData);
+  this.reset();
+}
+
+/**
+ * The listener of the `zlib.InflateRaw` stream `'error'` event.
+ *
+ * @param {Error} err The emitted error
+ * @private
+ */
+function inflateOnError(err) {
+  //
+  // There is no need to call `Zlib#close()` as the handle is automatically
+  // closed when an error is emitted.
+  //
+  this[kPerMessageDeflate]._inflate = null;
+  err[kStatusCode] = 1007;
+  this[kCallback](err);
+}

engine/ds-screencast/node_modules/chrome-remote-interface/node_modules/ws/lib/receiver.js

@@ -0,0 +1,607 @@
+'use strict';
+
+const { Writable } = require('stream');
+
+const PerMessageDeflate = require('./permessage-deflate');
+const {
+  BINARY_TYPES,
+  EMPTY_BUFFER,
+  kStatusCode,
+  kWebSocket
+} = require('./constants');
+const { concat, toArrayBuffer, unmask } = require('./buffer-util');
+const { isValidStatusCode, isValidUTF8 } = require('./validation');
+
+const GET_INFO = 0;
+const GET_PAYLOAD_LENGTH_16 = 1;
+const GET_PAYLOAD_LENGTH_64 = 2;
+const GET_MASK = 3;
+const GET_DATA = 4;
+const INFLATING = 5;
+
+/**
+ * HyBi Receiver implementation.
+ *
+ * @extends Writable
+ */
+class Receiver extends Writable {
+  /**
+   * Creates a Receiver instance.
+   *
+   * @param {String} [binaryType=nodebuffer] The type for binary data
+   * @param {Object} [extensions] An object containing the negotiated extensions
+   * @param {Boolean} [isServer=false] Specifies whether to operate in client or
+   *     server mode
+   * @param {Number} [maxPayload=0] The maximum allowed message length
+   */
+  constructor(binaryType, extensions, isServer, maxPayload) {
+    super();
+
+    this._binaryType = binaryType || BINARY_TYPES[0];
+    this[kWebSocket] = undefined;
+    this._extensions = extensions || {};
+    this._isServer = !!isServer;
+    this._maxPayload = maxPayload | 0;
+
+    this._bufferedBytes = 0;
+    this._buffers = [];
+
+    this._compressed = false;
+    this._payloadLength = 0;
+    this._mask = undefined;
+    this._fragmented = 0;
+    this._masked = false;
+    this._fin = false;
+    this._opcode = 0;
+
+    this._totalPayloadLength = 0;
+    this._messageLength = 0;
+    this._fragments = [];
+
+    this._state = GET_INFO;
+    this._loop = false;
+  }
+
+  /**
+   * Implements `Writable.prototype._write()`.
+   *
+   * @param {Buffer} chunk The chunk of data to write
+   * @param {String} encoding The character encoding of `chunk`
+   * @param {Function} cb Callback
+   * @private
+   */
+  _write(chunk, encoding, cb) {
+    if (this._opcode === 0x08 && this._state == GET_INFO) return cb();
+
+    this._bufferedBytes += chunk.length;
+    this._buffers.push(chunk);
+    this.startLoop(cb);
+  }
+
+  /**
+   * Consumes `n` bytes from the buffered data.
+   *
+   * @param {Number} n The number of bytes to consume
+   * @return {Buffer} The consumed bytes
+   * @private
+   */
+  consume(n) {
+    this._bufferedBytes -= n;
+
+    if (n === this._buffers[0].length) return this._buffers.shift();
+
+    if (n < this._buffers[0].length) {
+      const buf = this._buffers[0];
+      this._buffers[0] = buf.slice(n);
+      return buf.slice(0, n);
+    }
+
+    const dst = Buffer.allocUnsafe(n);
+
+    do {
+      const buf = this._buffers[0];
+      const offset = dst.length - n;
+
+      if (n >= buf.length) {
+        dst.set(this._buffers.shift(), offset);
+      } else {
+        dst.set(new Uint8Array(buf.buffer, buf.byteOffset, n), offset);
+        this._buffers[0] = buf.slice(n);
+      }
+
+      n -= buf.length;
+    } while (n > 0);
+
+    return dst;
+  }
+
+  /**
+   * Starts the parsing loop.
+   *
+   * @param {Function} cb Callback
+   * @private
+   */
+  startLoop(cb) {
+    let err;
+    this._loop = true;
+
+    do {
+      switch (this._state) {
+        case GET_INFO:
+          err = this.getInfo();
+          break;
+        case GET_PAYLOAD_LENGTH_16:
+          err = this.getPayloadLength16();
+          break;
+        case GET_PAYLOAD_LENGTH_64:
+          err = this.getPayloadLength64();
+          break;
+        case GET_MASK:
+          this.getMask();
+          break;
+        case GET_DATA:
+          err = this.getData(cb);
+          break;
+        default:
+          // `INFLATING`
+          this._loop = false;
+          return;
+      }
+    } while (this._loop);
+
+    cb(err);
+  }
+
+  /**
+   * Reads the first two bytes of a frame.
+   *
+   * @return {(RangeError|undefined)} A possible error
+   * @private
+   */
+  getInfo() {
+    if (this._bufferedBytes < 2) {
+      this._loop = false;
+      return;
+    }
+
+    const buf = this.consume(2);
+
+    if ((buf[0] & 0x30) !== 0x00) {
+      this._loop = false;
+      return error(
+        RangeError,
+        'RSV2 and RSV3 must be clear',
+        true,
+        1002,
+        'WS_ERR_UNEXPECTED_RSV_2_3'
+      );
+    }
+
+    const compressed = (buf[0] & 0x40) === 0x40;
+
+    if (compressed && !this._extensions[PerMessageDeflate.extensionName]) {
+      this._loop = false;
+      return error(
+        RangeError,
+        'RSV1 must be clear',
+        true,
+        1002,
+        'WS_ERR_UNEXPECTED_RSV_1'
+      );
+    }
+
+    this._fin = (buf[0] & 0x80) === 0x80;
+    this._opcode = buf[0] & 0x0f;
+    this._payloadLength = buf[1] & 0x7f;
+
+    if (this._opcode === 0x00) {
+      if (compressed) {
+        this._loop = false;
+        return error(
+          RangeError,
+          'RSV1 must be clear',
+          true,
+          1002,
+          'WS_ERR_UNEXPECTED_RSV_1'
+        );
+      }
+
+      if (!this._fragmented) {
+        this._loop = false;
+        return error(
+          RangeError,
+          'invalid opcode 0',
+          true,
+          1002,
+          'WS_ERR_INVALID_OPCODE'
+        );
+      }
+
+      this._opcode = this._fragmented;
+    } else if (this._opcode === 0x01 || this._opcode === 0x02) {
+      if (this._fragmented) {
+        this._loop = false;
+        return error(
+          RangeError,
+          `invalid opcode ${this._opcode}`,
+          true,
+          1002,
+          'WS_ERR_INVALID_OPCODE'
+        );
+      }
+
+      this._compressed = compressed;
+    } else if (this._opcode > 0x07 && this._opcode < 0x0b) {
+      if (!this._fin) {
+        this._loop = false;
+        return error(
+          RangeError,
+          'FIN must be set',
+          true,
+          1002,
+          'WS_ERR_EXPECTED_FIN'
+        );
+      }
+
+      if (compressed) {
+        this._loop = false;
+        return error(
+          RangeError,
+          'RSV1 must be clear',
+          true,
+          1002,
+          'WS_ERR_UNEXPECTED_RSV_1'
+        );
+      }
+
+      if (this._payloadLength > 0x7d) {
+        this._loop = false;
+        return error(
+          RangeError,
+          `invalid payload length ${this._payloadLength}`,
+          true,
+          1002,
+          'WS_ERR_INVALID_CONTROL_PAYLOAD_LENGTH'
+        );
+      }
+    } else {
+      this._loop = false;
+      return error(
+        RangeError,
+        `invalid opcode ${this._opcode}`,
+        true,
+        1002,
+        'WS_ERR_INVALID_OPCODE'
+      );
+    }
+
+    if (!this._fin && !this._fragmented) this._fragmented = this._opcode;
+    this._masked = (buf[1] & 0x80) === 0x80;
+
+    if (this._isServer) {
+      if (!this._masked) {
+        this._loop = false;
+        return error(
+          RangeError,
+          'MASK must be set',
+          true,
+          1002,
+          'WS_ERR_EXPECTED_MASK'
+        );
+      }
+    } else if (this._masked) {
+      this._loop = false;
+      return error(
+        RangeError,
+        'MASK must be clear',
+        true,
+        1002,
+        'WS_ERR_UNEXPECTED_MASK'
+      );
+    }
+
+    if (this._payloadLength === 126) this._state = GET_PAYLOAD_LENGTH_16;
+    else if (this._payloadLength === 127) this._state = GET_PAYLOAD_LENGTH_64;
+    else return this.haveLength();
+  }
+
+  /**
+   * Gets extended payload length (7+16).
+   *
+   * @return {(RangeError|undefined)} A possible error
+   * @private
+   */
+  getPayloadLength16() {
+    if (this._bufferedBytes < 2) {
+      this._loop = false;
+      return;
+    }
+
+    this._payloadLength = this.consume(2).readUInt16BE(0);
+    return this.haveLength();
+  }
+
+  /**
+   * Gets extended payload length (7+64).
+   *
+   * @return {(RangeError|undefined)} A possible error
+   * @private
+   */
+  getPayloadLength64() {
+    if (this._bufferedBytes < 8) {
+      this._loop = false;
+      return;
+    }
+
+    const buf = this.consume(8);
+    const num = buf.readUInt32BE(0);
+
+    //
+    // The maximum safe integer in JavaScript is 2^53 - 1. An error is returned
+    // if payload length is greater than this number.
+    //
+    if (num > Math.pow(2, 53 - 32) - 1) {
+      this._loop = false;
+      return error(
+        RangeError,
+        'Unsupported WebSocket frame: payload length > 2^53 - 1',
+        false,
+        1009,
+        'WS_ERR_UNSUPPORTED_DATA_PAYLOAD_LENGTH'
+      );
+    }
+
+    this._payloadLength = num * Math.pow(2, 32) + buf.readUInt32BE(4);
+    return this.haveLength();
+  }
+
+  /**
+   * Payload length has been read.
+   *
+   * @return {(RangeError|undefined)} A possible error
+   * @private
+   */
+  haveLength() {
+    if (this._payloadLength && this._opcode < 0x08) {
+      this._totalPayloadLength += this._payloadLength;
+      if (this._totalPayloadLength > this._maxPayload && this._maxPayload > 0) {
+        this._loop = false;
+        return error(
+          RangeError,
+          'Max payload size exceeded',
+          false,
+          1009,
+          'WS_ERR_UNSUPPORTED_MESSAGE_LENGTH'
+        );
+      }
+    }
+
+    if (this._masked) this._state = GET_MASK;
+    else this._state = GET_DATA;
+  }
+
+  /**
+   * Reads mask bytes.
+   *
+   * @private
+   */
+  getMask() {
+    if (this._bufferedBytes < 4) {
+      this._loop = false;
+      return;
+    }
+
+    this._mask = this.consume(4);
+    this._state = GET_DATA;
+  }
+
+  /**
+   * Reads data bytes.
+   *
+   * @param {Function} cb Callback
+   * @return {(Error|RangeError|undefined)} A possible error
+   * @private
+   */
+  getData(cb) {
+    let data = EMPTY_BUFFER;
+
+    if (this._payloadLength) {
+      if (this._bufferedBytes < this._payloadLength) {
+        this._loop = false;
+        return;
+      }
+
+      data = this.consume(this._payloadLength);
+      if (this._masked) unmask(data, this._mask);
+    }
+
+    if (this._opcode > 0x07) return this.controlMessage(data);
+
+    if (this._compressed) {
+      this._state = INFLATING;
+      this.decompress(data, cb);
+      return;
+    }
+
+    if (data.length) {
+      //
+      // This message is not compressed so its lenght is the sum of the payload
+      // length of all fragments.
+      //
+      this._messageLength = this._totalPayloadLength;
+      this._fragments.push(data);
+    }
+
+    return this.dataMessage();
+  }
+
+  /**
+   * Decompresses data.
+   *
+   * @param {Buffer} data Compressed data
+   * @param {Function} cb Callback
+   * @private
+   */
+  decompress(data, cb) {
+    const perMessageDeflate = this._extensions[PerMessageDeflate.extensionName];
+
+    perMessageDeflate.decompress(data, this._fin, (err, buf) => {
+      if (err) return cb(err);
+
+      if (buf.length) {
+        this._messageLength += buf.length;
+        if (this._messageLength > this._maxPayload && this._maxPayload > 0) {
+          return cb(
+            error(
+              RangeError,
+              'Max payload size exceeded',
+              false,
+              1009,
+              'WS_ERR_UNSUPPORTED_MESSAGE_LENGTH'
+            )
+          );
+        }
+
+        this._fragments.push(buf);
+      }
+
+      const er = this.dataMessage();
+      if (er) return cb(er);
+
+      this.startLoop(cb);
+    });
+  }
+
+  /**
+   * Handles a data message.
+   *
+   * @return {(Error|undefined)} A possible error
+   * @private
+   */
+  dataMessage() {
+    if (this._fin) {
+      const messageLength = this._messageLength;
+      const fragments = this._fragments;
+
+      this._totalPayloadLength = 0;
+      this._messageLength = 0;
+      this._fragmented = 0;
+      this._fragments = [];
+
+      if (this._opcode === 2) {
+        let data;
+
+        if (this._binaryType === 'nodebuffer') {
+          data = concat(fragments, messageLength);
+        } else if (this._binaryType === 'arraybuffer') {
+          data = toArrayBuffer(concat(fragments, messageLength));
+        } else {
+          data = fragments;
+        }
+
+        this.emit('message', data);
+      } else {
+        const buf = concat(fragments, messageLength);
+
+        if (!isValidUTF8(buf)) {
+          this._loop = false;
+          return error(
+            Error,
+            'invalid UTF-8 sequence',
+            true,
+            1007,
+            'WS_ERR_INVALID_UTF8'
+          );
+        }
+
+        this.emit('message', buf.toString());
+      }
+    }
+
+    this._state = GET_INFO;
+  }
+
+  /**
+   * Handles a control message.
+   *
+   * @param {Buffer} data Data to handle
+   * @return {(Error|RangeError|undefined)} A possible error
+   * @private
+   */
+  controlMessage(data) {
+    if (this._opcode === 0x08) {
+      this._loop = false;
+
+      if (data.length === 0) {
+        this.emit('conclude', 1005, '');
+        this.end();
+      } else if (data.length === 1) {
+        return error(
+          RangeError,
+          'invalid payload length 1',
+          true,
+          1002,
+          'WS_ERR_INVALID_CONTROL_PAYLOAD_LENGTH'
+        );
+      } else {
+        const code = data.readUInt16BE(0);
+
+        if (!isValidStatusCode(code)) {
+          return error(
+            RangeError,
+            `invalid status code ${code}`,
+            true,
+            1002,
+            'WS_ERR_INVALID_CLOSE_CODE'
+          );
+        }
+
+        const buf = data.slice(2);
+
+        if (!isValidUTF8(buf)) {
+          return error(
+            Error,
+            'invalid UTF-8 sequence',
+            true,
+            1007,
+            'WS_ERR_INVALID_UTF8'
+          );
+        }
+
+        this.emit('conclude', code, buf.toString());
+        this.end();
+      }
+    } else if (this._opcode === 0x09) {
+      this.emit('ping', data);
+    } else {
+      this.emit('pong', data);
+    }
+
+    this._state = GET_INFO;
+  }
+}
+
+module.exports = Receiver;
+
+/**
+ * Builds an error object.
+ *
+ * @param {function(new:Error|RangeError)} ErrorCtor The error constructor
+ * @param {String} message The error message
+ * @param {Boolean} prefix Specifies whether or not to add a default prefix to
+ *     `message`
+ * @param {Number} statusCode The status code
+ * @param {String} errorCode The exposed error code
+ * @return {(Error|RangeError)} The error
+ * @private
+ */
+function error(ErrorCtor, message, prefix, statusCode, errorCode) {
+  const err = new ErrorCtor(
+    prefix ? `Invalid WebSocket frame: ${message}` : message
+  );
+
+  Error.captureStackTrace(err, error);
+  err.code = errorCode;
+  err[kStatusCode] = statusCode;
+  return err;
+}

engine/ds-screencast/node_modules/chrome-remote-interface/node_modules/ws/lib/sender.js

@@ -0,0 +1,409 @@
+/* eslint no-unused-vars: ["error", { "varsIgnorePattern": "^net|tls$" }] */
+
+'use strict';
+
+const net = require('net');
+const tls = require('tls');
+const { randomFillSync } = require('crypto');
+
+const PerMessageDeflate = require('./permessage-deflate');
+const { EMPTY_BUFFER } = require('./constants');
+const { isValidStatusCode } = require('./validation');
+const { mask: applyMask, toBuffer } = require('./buffer-util');
+
+const mask = Buffer.alloc(4);
+
+/**
+ * HyBi Sender implementation.
+ */
+class Sender {
+  /**
+   * Creates a Sender instance.
+   *
+   * @param {(net.Socket|tls.Socket)} socket The connection socket
+   * @param {Object} [extensions] An object containing the negotiated extensions
+   */
+  constructor(socket, extensions) {
+    this._extensions = extensions || {};
+    this._socket = socket;
+
+    this._firstFragment = true;
+    this._compress = false;
+
+    this._bufferedBytes = 0;
+    this._deflating = false;
+    this._queue = [];
+  }
+
+  /**
+   * Frames a piece of data according to the HyBi WebSocket protocol.
+   *
+   * @param {Buffer} data The data to frame
+   * @param {Object} options Options object
+   * @param {Number} options.opcode The opcode
+   * @param {Boolean} [options.readOnly=false] Specifies whether `data` can be
+   *     modified
+   * @param {Boolean} [options.fin=false] Specifies whether or not to set the
+   *     FIN bit
+   * @param {Boolean} [options.mask=false] Specifies whether or not to mask
+   *     `data`
+   * @param {Boolean} [options.rsv1=false] Specifies whether or not to set the
+   *     RSV1 bit
+   * @return {Buffer[]} The framed data as a list of `Buffer` instances
+   * @public
+   */
+  static frame(data, options) {
+    const merge = options.mask && options.readOnly;
+    let offset = options.mask ? 6 : 2;
+    let payloadLength = data.length;
+
+    if (data.length >= 65536) {
+      offset += 8;
+      payloadLength = 127;
+    } else if (data.length > 125) {
+      offset += 2;
+      payloadLength = 126;
+    }
+
+    const target = Buffer.allocUnsafe(merge ? data.length + offset : offset);
+
+    target[0] = options.fin ? options.opcode | 0x80 : options.opcode;
+    if (options.rsv1) target[0] |= 0x40;
+
+    target[1] = payloadLength;
+
+    if (payloadLength === 126) {
+      target.writeUInt16BE(data.length, 2);
+    } else if (payloadLength === 127) {
+      target.writeUInt32BE(0, 2);
+      target.writeUInt32BE(data.length, 6);
+    }
+
+    if (!options.mask) return [target, data];
+
+    randomFillSync(mask, 0, 4);
+
+    target[1] |= 0x80;
+    target[offset - 4] = mask[0];
+    target[offset - 3] = mask[1];
+    target[offset - 2] = mask[2];
+    target[offset - 1] = mask[3];
+
+    if (merge) {
+      applyMask(data, mask, target, offset, data.length);
+      return [target];
+    }
+
+    applyMask(data, mask, data, 0, data.length);
+    return [target, data];
+  }
+
+  /**
+   * Sends a close message to the other peer.
+   *
+   * @param {Number} [code] The status code component of the body
+   * @param {String} [data] The message component of the body
+   * @param {Boolean} [mask=false] Specifies whether or not to mask the message
+   * @param {Function} [cb] Callback
+   * @public
+   */
+  close(code, data, mask, cb) {
+    let buf;
+
+    if (code === undefined) {
+      buf = EMPTY_BUFFER;
+    } else if (typeof code !== 'number' || !isValidStatusCode(code)) {
+      throw new TypeError('First argument must be a valid error code number');
+    } else if (data === undefined || data === '') {
+      buf = Buffer.allocUnsafe(2);
+      buf.writeUInt16BE(code, 0);
+    } else {
+      const length = Buffer.byteLength(data);
+
+      if (length > 123) {
+        throw new RangeError('The message must not be greater than 123 bytes');
+      }
+
+      buf = Buffer.allocUnsafe(2 + length);
+      buf.writeUInt16BE(code, 0);
+      buf.write(data, 2);
+    }
+
+    if (this._deflating) {
+      this.enqueue([this.doClose, buf, mask, cb]);
+    } else {
+      this.doClose(buf, mask, cb);
+    }
+  }
+
+  /**
+   * Frames and sends a close message.
+   *
+   * @param {Buffer} data The message to send
+   * @param {Boolean} [mask=false] Specifies whether or not to mask `data`
+   * @param {Function} [cb] Callback
+   * @private
+   */
+  doClose(data, mask, cb) {
+    this.sendFrame(
+      Sender.frame(data, {
+        fin: true,
+        rsv1: false,
+        opcode: 0x08,
+        mask,
+        readOnly: false
+      }),
+      cb
+    );
+  }
+
+  /**
+   * Sends a ping message to the other peer.
+   *
+   * @param {*} data The message to send
+   * @param {Boolean} [mask=false] Specifies whether or not to mask `data`
+   * @param {Function} [cb] Callback
+   * @public
+   */
+  ping(data, mask, cb) {
+    const buf = toBuffer(data);
+
+    if (buf.length > 125) {
+      throw new RangeError('The data size must not be greater than 125 bytes');
+    }
+
+    if (this._deflating) {
+      this.enqueue([this.doPing, buf, mask, toBuffer.readOnly, cb]);
+    } else {
+      this.doPing(buf, mask, toBuffer.readOnly, cb);
+    }
+  }
+
+  /**
+   * Frames and sends a ping message.
+   *
+   * @param {Buffer} data The message to send
+   * @param {Boolean} [mask=false] Specifies whether or not to mask `data`
+   * @param {Boolean} [readOnly=false] Specifies whether `data` can be modified
+   * @param {Function} [cb] Callback
+   * @private
+   */
+  doPing(data, mask, readOnly, cb) {
+    this.sendFrame(
+      Sender.frame(data, {
+        fin: true,
+        rsv1: false,
+        opcode: 0x09,
+        mask,
+        readOnly
+      }),
+      cb
+    );
+  }
+
+  /**
+   * Sends a pong message to the other peer.
+   *
+   * @param {*} data The message to send
+   * @param {Boolean} [mask=false] Specifies whether or not to mask `data`
+   * @param {Function} [cb] Callback
+   * @public
+   */
+  pong(data, mask, cb) {
+    const buf = toBuffer(data);
+
+    if (buf.length > 125) {
+      throw new RangeError('The data size must not be greater than 125 bytes');
+    }
+
+    if (this._deflating) {
+      this.enqueue([this.doPong, buf, mask, toBuffer.readOnly, cb]);
+    } else {
+      this.doPong(buf, mask, toBuffer.readOnly, cb);
+    }
+  }
+
+  /**
+   * Frames and sends a pong message.
+   *
+   * @param {Buffer} data The message to send
+   * @param {Boolean} [mask=false] Specifies whether or not to mask `data`
+   * @param {Boolean} [readOnly=false] Specifies whether `data` can be modified
+   * @param {Function} [cb] Callback
+   * @private
+   */
+  doPong(data, mask, readOnly, cb) {
+    this.sendFrame(
+      Sender.frame(data, {
+        fin: true,
+        rsv1: false,
+        opcode: 0x0a,
+        mask,
+        readOnly
+      }),
+      cb
+    );
+  }
+
+  /**
+   * Sends a data message to the other peer.
+   *
+   * @param {*} data The message to send
+   * @param {Object} options Options object
+   * @param {Boolean} [options.compress=false] Specifies whether or not to
+   *     compress `data`
+   * @param {Boolean} [options.binary=false] Specifies whether `data` is binary
+   *     or text
+   * @param {Boolean} [options.fin=false] Specifies whether the fragment is the
+   *     last one
+   * @param {Boolean} [options.mask=false] Specifies whether or not to mask
+   *     `data`
+   * @param {Function} [cb] Callback
+   * @public
+   */
+  send(data, options, cb) {
+    const buf = toBuffer(data);
+    const perMessageDeflate = this._extensions[PerMessageDeflate.extensionName];
+    let opcode = options.binary ? 2 : 1;
+    let rsv1 = options.compress;
+
+    if (this._firstFragment) {
+      this._firstFragment = false;
+      if (rsv1 && perMessageDeflate) {
+        rsv1 = buf.length >= perMessageDeflate._threshold;
+      }
+      this._compress = rsv1;
+    } else {
+      rsv1 = false;
+      opcode = 0;
+    }
+
+    if (options.fin) this._firstFragment = true;
+
+    if (perMessageDeflate) {
+      const opts = {
+        fin: options.fin,
+        rsv1,
+        opcode,
+        mask: options.mask,
+        readOnly: toBuffer.readOnly
+      };
+
+      if (this._deflating) {
+        this.enqueue([this.dispatch, buf, this._compress, opts, cb]);
+      } else {
+        this.dispatch(buf, this._compress, opts, cb);
+      }
+    } else {
+      this.sendFrame(
+        Sender.frame(buf, {
+          fin: options.fin,
+          rsv1: false,
+          opcode,
+          mask: options.mask,
+          readOnly: toBuffer.readOnly
+        }),
+        cb
+      );
+    }
+  }
+
+  /**
+   * Dispatches a data message.
+   *
+   * @param {Buffer} data The message to send
+   * @param {Boolean} [compress=false] Specifies whether or not to compress
+   *     `data`
+   * @param {Object} options Options object
+   * @param {Number} options.opcode The opcode
+   * @param {Boolean} [options.readOnly=false] Specifies whether `data` can be
+   *     modified
+   * @param {Boolean} [options.fin=false] Specifies whether or not to set the
+   *     FIN bit
+   * @param {Boolean} [options.mask=false] Specifies whether or not to mask
+   *     `data`
+   * @param {Boolean} [options.rsv1=false] Specifies whether or not to set the
+   *     RSV1 bit
+   * @param {Function} [cb] Callback
+   * @private
+   */
+  dispatch(data, compress, options, cb) {
+    if (!compress) {
+      this.sendFrame(Sender.frame(data, options), cb);
+      return;
+    }
+
+    const perMessageDeflate = this._extensions[PerMessageDeflate.extensionName];
+
+    this._bufferedBytes += data.length;
+    this._deflating = true;
+    perMessageDeflate.compress(data, options.fin, (_, buf) => {
+      if (this._socket.destroyed) {
+        const err = new Error(
+          'The socket was closed while data was being compressed'
+        );
+
+        if (typeof cb === 'function') cb(err);
+
+        for (let i = 0; i < this._queue.length; i++) {
+          const callback = this._queue[i][4];
+
+          if (typeof callback === 'function') callback(err);
+        }
+
+        return;
+      }
+
+      this._bufferedBytes -= data.length;
+      this._deflating = false;
+      options.readOnly = false;
+      this.sendFrame(Sender.frame(buf, options), cb);
+      this.dequeue();
+    });
+  }
+
+  /**
+   * Executes queued send operations.
+   *
+   * @private
+   */
+  dequeue() {
+    while (!this._deflating && this._queue.length) {
+      const params = this._queue.shift();
+
+      this._bufferedBytes -= params[1].length;
+      Reflect.apply(params[0], this, params.slice(1));
+    }
+  }
+
+  /**
+   * Enqueues a send operation.
+   *
+   * @param {Array} params Send operation parameters.
+   * @private
+   */
+  enqueue(params) {
+    this._bufferedBytes += params[1].length;
+    this._queue.push(params);
+  }
+
+  /**
+   * Sends a frame.
+   *
+   * @param {Buffer[]} list The frame to send
+   * @param {Function} [cb] Callback
+   * @private
+   */
+  sendFrame(list, cb) {
+    if (list.length === 2) {
+      this._socket.cork();
+      this._socket.write(list[0]);
+      this._socket.write(list[1], cb);
+      this._socket.uncork();
+    } else {
+      this._socket.write(list[0], cb);
+    }
+  }
+}
+
+module.exports = Sender;

engine/ds-screencast/node_modules/chrome-remote-interface/node_modules/ws/lib/stream.js

@@ -0,0 +1,180 @@
+'use strict';
+
+const { Duplex } = require('stream');
+
+/**
+ * Emits the `'close'` event on a stream.
+ *
+ * @param {Duplex} stream The stream.
+ * @private
+ */
+function emitClose(stream) {
+  stream.emit('close');
+}
+
+/**
+ * The listener of the `'end'` event.
+ *
+ * @private
+ */
+function duplexOnEnd() {
+  if (!this.destroyed && this._writableState.finished) {
+    this.destroy();
+  }
+}
+
+/**
+ * The listener of the `'error'` event.
+ *
+ * @param {Error} err The error
+ * @private
+ */
+function duplexOnError(err) {
+  this.removeListener('error', duplexOnError);
+  this.destroy();
+  if (this.listenerCount('error') === 0) {
+    // Do not suppress the throwing behavior.
+    this.emit('error', err);
+  }
+}
+
+/**
+ * Wraps a `WebSocket` in a duplex stream.
+ *
+ * @param {WebSocket} ws The `WebSocket` to wrap
+ * @param {Object} [options] The options for the `Duplex` constructor
+ * @return {Duplex} The duplex stream
+ * @public
+ */
+function createWebSocketStream(ws, options) {
+  let resumeOnReceiverDrain = true;
+  let terminateOnDestroy = true;
+
+  function receiverOnDrain() {
+    if (resumeOnReceiverDrain) ws._socket.resume();
+  }
+
+  if (ws.readyState === ws.CONNECTING) {
+    ws.once('open', function open() {
+      ws._receiver.removeAllListeners('drain');
+      ws._receiver.on('drain', receiverOnDrain);
+    });
+  } else {
+    ws._receiver.removeAllListeners('drain');
+    ws._receiver.on('drain', receiverOnDrain);
+  }
+
+  const duplex = new Duplex({
+    ...options,
+    autoDestroy: false,
+    emitClose: false,
+    objectMode: false,
+    writableObjectMode: false
+  });
+
+  ws.on('message', function message(msg) {
+    if (!duplex.push(msg)) {
+      resumeOnReceiverDrain = false;
+      ws._socket.pause();
+    }
+  });
+
+  ws.once('error', function error(err) {
+    if (duplex.destroyed) return;
+
+    // Prevent `ws.terminate()` from being called by `duplex._destroy()`.
+    //
+    // - If the `'error'` event is emitted before the `'open'` event, then
+    //   `ws.terminate()` is a noop as no socket is assigned.
+    // - Otherwise, the error is re-emitted by the listener of the `'error'`
+    //   event of the `Receiver` object. The listener already closes the
+    //   connection by calling `ws.close()`. This allows a close frame to be
+    //   sent to the other peer. If `ws.terminate()` is called right after this,
+    //   then the close frame might not be sent.
+    terminateOnDestroy = false;
+    duplex.destroy(err);
+  });
+
+  ws.once('close', function close() {
+    if (duplex.destroyed) return;
+
+    duplex.push(null);
+  });
+
+  duplex._destroy = function (err, callback) {
+    if (ws.readyState === ws.CLOSED) {
+      callback(err);
+      process.nextTick(emitClose, duplex);
+      return;
+    }
+
+    let called = false;
+
+    ws.once('error', function error(err) {
+      called = true;
+      callback(err);
+    });
+
+    ws.once('close', function close() {
+      if (!called) callback(err);
+      process.nextTick(emitClose, duplex);
+    });
+
+    if (terminateOnDestroy) ws.terminate();
+  };
+
+  duplex._final = function (callback) {
+    if (ws.readyState === ws.CONNECTING) {
+      ws.once('open', function open() {
+        duplex._final(callback);
+      });
+      return;
+    }
+
+    // If the value of the `_socket` property is `null` it means that `ws` is a
+    // client websocket and the handshake failed. In fact, when this happens, a
+    // socket is never assigned to the websocket. Wait for the `'error'` event
+    // that will be emitted by the websocket.
+    if (ws._socket === null) return;
+
+    if (ws._socket._writableState.finished) {
+      callback();
+      if (duplex._readableState.endEmitted) duplex.destroy();
+    } else {
+      ws._socket.once('finish', function finish() {
+        // `duplex` is not destroyed here because the `'end'` event will be
+        // emitted on `duplex` after this `'finish'` event. The EOF signaling
+        // `null` chunk is, in fact, pushed when the websocket emits `'close'`.
+        callback();
+      });
+      ws.close();
+    }
+  };
+
+  duplex._read = function () {
+    if (
+      (ws.readyState === ws.OPEN || ws.readyState === ws.CLOSING) &&
+      !resumeOnReceiverDrain
+    ) {
+      resumeOnReceiverDrain = true;
+      if (!ws._receiver._writableState.needDrain) ws._socket.resume();
+    }
+  };
+
+  duplex._write = function (chunk, encoding, callback) {
+    if (ws.readyState === ws.CONNECTING) {
+      ws.once('open', function open() {
+        duplex._write(chunk, encoding, callback);
+      });
+      return;
+    }
+
+    ws.send(chunk, callback);
+  };
+
+  duplex.on('end', duplexOnEnd);
+  duplex.on('error', duplexOnError);
+  return duplex;
+}
+
+module.exports = createWebSocketStream;

engine/ds-screencast/node_modules/chrome-remote-interface/node_modules/ws/lib/validation.js

@@ -0,0 +1,104 @@
+'use strict';
+
+/**
+ * Checks if a status code is allowed in a close frame.
+ *
+ * @param {Number} code The status code
+ * @return {Boolean} `true` if the status code is valid, else `false`
+ * @public
+ */
+function isValidStatusCode(code) {
+  return (
+    (code >= 1000 &&
+      code <= 1014 &&
+      code !== 1004 &&
+      code !== 1005 &&
+      code !== 1006) ||
+    (code >= 3000 && code <= 4999)
+  );
+}
+
+/**
+ * Checks if a given buffer contains only correct UTF-8.
+ * Ported from https://www.cl.cam.ac.uk/%7Emgk25/ucs/utf8_check.c by
+ * Markus Kuhn.
+ *
+ * @param {Buffer} buf The buffer to check
+ * @return {Boolean} `true` if `buf` contains only correct UTF-8, else `false`
+ * @public
+ */
+function _isValidUTF8(buf) {
+  const len = buf.length;
+  let i = 0;
+
+  while (i < len) {
+    if ((buf[i] & 0x80) === 0) {
+      // 0xxxxxxx
+      i++;
+    } else if ((buf[i] & 0xe0) === 0xc0) {
+      // 110xxxxx 10xxxxxx
+      if (
+        i + 1 === len ||
+        (buf[i + 1] & 0xc0) !== 0x80 ||
+        (buf[i] & 0xfe) === 0xc0 // Overlong
+      ) {
+        return false;
+      }
+
+      i += 2;
+    } else if ((buf[i] & 0xf0) === 0xe0) {
+      // 1110xxxx 10xxxxxx 10xxxxxx
+      if (
+        i + 2 >= len ||
+        (buf[i + 1] & 0xc0) !== 0x80 ||
+        (buf[i + 2] & 0xc0) !== 0x80 ||
+        (buf[i] === 0xe0 && (buf[i + 1] & 0xe0) === 0x80) || // Overlong
+        (buf[i] === 0xed && (buf[i + 1] & 0xe0) === 0xa0) // Surrogate (U+D800 - U+DFFF)
+      ) {
+        return false;
+      }
+
+      i += 3;
+    } else if ((buf[i] & 0xf8) === 0xf0) {
+      // 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
+      if (
+        i + 3 >= len ||
+        (buf[i + 1] & 0xc0) !== 0x80 ||
+        (buf[i + 2] & 0xc0) !== 0x80 ||
+        (buf[i + 3] & 0xc0) !== 0x80 ||
+        (buf[i] === 0xf0 && (buf[i + 1] & 0xf0) === 0x80) || // Overlong
+        (buf[i] === 0xf4 && buf[i + 1] > 0x8f) ||
+        buf[i] > 0xf4 // > U+10FFFF
+      ) {
+        return false;
+      }
+
+      i += 4;
+    } else {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+try {
+  let isValidUTF8 = require('utf-8-validate');
+
+  /* istanbul ignore if */
+  if (typeof isValidUTF8 === 'object') {
+    isValidUTF8 = isValidUTF8.Validation.isValidUTF8; // utf-8-validate@<3.0.0
+  }
+
+  module.exports = {
+    isValidStatusCode,
+    isValidUTF8(buf) {
+      return buf.length < 150 ? _isValidUTF8(buf) : isValidUTF8(buf);
+    }
+  };
+} catch (e) /* istanbul ignore next */ {
+  module.exports = {
+    isValidStatusCode,
+    isValidUTF8: _isValidUTF8
+  };
+}

engine/ds-screencast/node_modules/chrome-remote-interface/node_modules/ws/lib/websocket-server.js

@@ -0,0 +1,449 @@
+/* eslint no-unused-vars: ["error", { "varsIgnorePattern": "^net|tls|https$" }] */
+
+'use strict';
+
+const EventEmitter = require('events');
+const http = require('http');
+const https = require('https');
+const net = require('net');
+const tls = require('tls');
+const { createHash } = require('crypto');
+
+const PerMessageDeflate = require('./permessage-deflate');
+const WebSocket = require('./websocket');
+const { format, parse } = require('./extension');
+const { GUID, kWebSocket } = require('./constants');
+
+const keyRegex = /^[+/0-9A-Za-z]{22}==$/;
+
+const RUNNING = 0;
+const CLOSING = 1;
+const CLOSED = 2;
+
+/**
+ * Class representing a WebSocket server.
+ *
+ * @extends EventEmitter
+ */
+class WebSocketServer extends EventEmitter {
+  /**
+   * Create a `WebSocketServer` instance.
+   *
+   * @param {Object} options Configuration options
+   * @param {Number} [options.backlog=511] The maximum length of the queue of
+   *     pending connections
+   * @param {Boolean} [options.clientTracking=true] Specifies whether or not to
+   *     track clients
+   * @param {Function} [options.handleProtocols] A hook to handle protocols
+   * @param {String} [options.host] The hostname where to bind the server
+   * @param {Number} [options.maxPayload=104857600] The maximum allowed message
+   *     size
+   * @param {Boolean} [options.noServer=false] Enable no server mode
+   * @param {String} [options.path] Accept only connections matching this path
+   * @param {(Boolean|Object)} [options.perMessageDeflate=false] Enable/disable
+   *     permessage-deflate
+   * @param {Number} [options.port] The port where to bind the server
+   * @param {(http.Server|https.Server)} [options.server] A pre-created HTTP/S
+   *     server to use
+   * @param {Function} [options.verifyClient] A hook to reject connections
+   * @param {Function} [callback] A listener for the `listening` event
+   */
+  constructor(options, callback) {
+    super();
+
+    options = {
+      maxPayload: 100 * 1024 * 1024,
+      perMessageDeflate: false,
+      handleProtocols: null,
+      clientTracking: true,
+      verifyClient: null,
+      noServer: false,
+      backlog: null, // use default (511 as implemented in net.js)
+      server: null,
+      host: null,
+      path: null,
+      port: null,
+      ...options
+    };
+
+    if (
+      (options.port == null && !options.server && !options.noServer) ||
+      (options.port != null && (options.server || options.noServer)) ||
+      (options.server && options.noServer)
+    ) {
+      throw new TypeError(
+        'One and only one of the "port", "server", or "noServer" options ' +
+          'must be specified'
+      );
+    }
+
+    if (options.port != null) {
+      this._server = http.createServer((req, res) => {
+        const body = http.STATUS_CODES[426];
+
+        res.writeHead(426, {
+          'Content-Length': body.length,
+          'Content-Type': 'text/plain'
+        });
+        res.end(body);
+      });
+      this._server.listen(
+        options.port,
+        options.host,
+        options.backlog,
+        callback
+      );
+    } else if (options.server) {
+      this._server = options.server;
+    }
+
+    if (this._server) {
+      const emitConnection = this.emit.bind(this, 'connection');
+
+      this._removeListeners = addListeners(this._server, {
+        listening: this.emit.bind(this, 'listening'),
+        error: this.emit.bind(this, 'error'),
+        upgrade: (req, socket, head) => {
+          this.handleUpgrade(req, socket, head, emitConnection);
+        }
+      });
+    }
+
+    if (options.perMessageDeflate === true) options.perMessageDeflate = {};
+    if (options.clientTracking) this.clients = new Set();
+    this.options = options;
+    this._state = RUNNING;
+  }
+
+  /**
+   * Returns the bound address, the address family name, and port of the server
+   * as reported by the operating system if listening on an IP socket.
+   * If the server is listening on a pipe or UNIX domain socket, the name is
+   * returned as a string.
+   *
+   * @return {(Object|String|null)} The address of the server
+   * @public
+   */
+  address() {
+    if (this.options.noServer) {
+      throw new Error('The server is operating in "noServer" mode');
+    }
+
+    if (!this._server) return null;
+    return this._server.address();
+  }
+
+  /**
+   * Close the server.
+   *
+   * @param {Function} [cb] Callback
+   * @public
+   */
+  close(cb) {
+    if (cb) this.once('close', cb);
+
+    if (this._state === CLOSED) {
+      process.nextTick(emitClose, this);
+      return;
+    }
+
+    if (this._state === CLOSING) return;
+    this._state = CLOSING;
+
+    //
+    // Terminate all associated clients.
+    //
+    if (this.clients) {
+      for (const client of this.clients) client.terminate();
+    }
+
+    const server = this._server;
+
+    if (server) {
+      this._removeListeners();
+      this._removeListeners = this._server = null;
+
+      //
+      // Close the http server if it was internally created.
+      //
+      if (this.options.port != null) {
+        server.close(emitClose.bind(undefined, this));
+        return;
+      }
+    }
+
+    process.nextTick(emitClose, this);
+  }
+
+  /**
+   * See if a given request should be handled by this server instance.
+   *
+   * @param {http.IncomingMessage} req Request object to inspect
+   * @return {Boolean} `true` if the request is valid, else `false`
+   * @public
+   */
+  shouldHandle(req) {
+    if (this.options.path) {
+      const index = req.url.indexOf('?');
+      const pathname = index !== -1 ? req.url.slice(0, index) : req.url;
+
+      if (pathname !== this.options.path) return false;
+    }
+
+    return true;
+  }
+
+  /**
+   * Handle a HTTP Upgrade request.
+   *
+   * @param {http.IncomingMessage} req The request object
+   * @param {(net.Socket|tls.Socket)} socket The network socket between the
+   *     server and client
+   * @param {Buffer} head The first packet of the upgraded stream
+   * @param {Function} cb Callback
+   * @public
+   */
+  handleUpgrade(req, socket, head, cb) {
+    socket.on('error', socketOnError);
+
+    const key =
+      req.headers['sec-websocket-key'] !== undefined
+        ? req.headers['sec-websocket-key'].trim()
+        : false;
+    const upgrade = req.headers.upgrade;
+    const version = +req.headers['sec-websocket-version'];
+    const extensions = {};
+
+    if (
+      req.method !== 'GET' ||
+      upgrade === undefined ||
+      upgrade.toLowerCase() !== 'websocket' ||
+      !key ||
+      !keyRegex.test(key) ||
+      (version !== 8 && version !== 13) ||
+      !this.shouldHandle(req)
+    ) {
+      return abortHandshake(socket, 400);
+    }
+
+    if (this.options.perMessageDeflate) {
+      const perMessageDeflate = new PerMessageDeflate(
+        this.options.perMessageDeflate,
+        true,
+        this.options.maxPayload
+      );
+
+      try {
+        const offers = parse(req.headers['sec-websocket-extensions']);
+
+        if (offers[PerMessageDeflate.extensionName]) {
+          perMessageDeflate.accept(offers[PerMessageDeflate.extensionName]);
+          extensions[PerMessageDeflate.extensionName] = perMessageDeflate;
+        }
+      } catch (err) {
+        return abortHandshake(socket, 400);
+      }
+    }
+
+    //
+    // Optionally call external client verification handler.
+    //
+    if (this.options.verifyClient) {
+      const info = {
+        origin:
+          req.headers[`${version === 8 ? 'sec-websocket-origin' : 'origin'}`],
+        secure: !!(req.socket.authorized || req.socket.encrypted),
+        req
+      };
+
+      if (this.options.verifyClient.length === 2) {
+        this.options.verifyClient(info, (verified, code, message, headers) => {
+          if (!verified) {
+            return abortHandshake(socket, code || 401, message, headers);
+          }
+
+          this.completeUpgrade(key, extensions, req, socket, head, cb);
+        });
+        return;
+      }
+
+      if (!this.options.verifyClient(info)) return abortHandshake(socket, 401);
+    }
+
+    this.completeUpgrade(key, extensions, req, socket, head, cb);
+  }
+
+  /**
+   * Upgrade the connection to WebSocket.
+   *
+   * @param {String} key The value of the `Sec-WebSocket-Key` header
+   * @param {Object} extensions The accepted extensions
+   * @param {http.IncomingMessage} req The request object
+   * @param {(net.Socket|tls.Socket)} socket The network socket between the
+   *     server and client
+   * @param {Buffer} head The first packet of the upgraded stream
+   * @param {Function} cb Callback
+   * @throws {Error} If called more than once with the same socket
+   * @private
+   */
+  completeUpgrade(key, extensions, req, socket, head, cb) {
+    //
+    // Destroy the socket if the client has already sent a FIN packet.
+    //
+    if (!socket.readable || !socket.writable) return socket.destroy();
+
+    if (socket[kWebSocket]) {
+      throw new Error(
+        'server.handleUpgrade() was called more than once with the same ' +
+          'socket, possibly due to a misconfiguration'
+      );
+    }
+
+    if (this._state > RUNNING) return abortHandshake(socket, 503);
+
+    const digest = createHash('sha1')
+      .update(key + GUID)
+      .digest('base64');
+
+    const headers = [
+      'HTTP/1.1 101 Switching Protocols',
+      'Upgrade: websocket',
+      'Connection: Upgrade',
+      `Sec-WebSocket-Accept: ${digest}`
+    ];
+
+    const ws = new WebSocket(null);
+    let protocol = req.headers['sec-websocket-protocol'];
+
+    if (protocol) {
+      protocol = protocol.split(',').map(trim);
+
+      //
+      // Optionally call external protocol selection handler.
+      //
+      if (this.options.handleProtocols) {
+        protocol = this.options.handleProtocols(protocol, req);
+      } else {
+        protocol = protocol[0];
+      }
+
+      if (protocol) {
+        headers.push(`Sec-WebSocket-Protocol: ${protocol}`);
+        ws._protocol = protocol;
+      }
+    }
+
+    if (extensions[PerMessageDeflate.extensionName]) {
+      const params = extensions[PerMessageDeflate.extensionName].params;
+      const value = format({
+        [PerMessageDeflate.extensionName]: [params]
+      });
+      headers.push(`Sec-WebSocket-Extensions: ${value}`);
+      ws._extensions = extensions;
+    }
+
+    //
+    // Allow external modification/inspection of handshake headers.
+    //
+    this.emit('headers', headers, req);
+
+    socket.write(headers.concat('\r\n').join('\r\n'));
+    socket.removeListener('error', socketOnError);
+
+    ws.setSocket(socket, head, this.options.maxPayload);
+
+    if (this.clients) {
+      this.clients.add(ws);
+      ws.on('close', () => this.clients.delete(ws));
+    }
+
+    cb(ws, req);
+  }
+}
+
+module.exports = WebSocketServer;
+
+/**
+ * Add event listeners on an `EventEmitter` using a map of <event, listener>
+ * pairs.
+ *
+ * @param {EventEmitter} server The event emitter
+ * @param {Object.<String, Function>} map The listeners to add
+ * @return {Function} A function that will remove the added listeners when
+ *     called
+ * @private
+ */
+function addListeners(server, map) {
+  for (const event of Object.keys(map)) server.on(event, map[event]);
+
+  return function removeListeners() {
+    for (const event of Object.keys(map)) {
+      server.removeListener(event, map[event]);
+    }
+  };
+}
+
+/**
+ * Emit a `'close'` event on an `EventEmitter`.
+ *
+ * @param {EventEmitter} server The event emitter
+ * @private
+ */
+function emitClose(server) {
+  server._state = CLOSED;
+  server.emit('close');
+}
+
+/**
+ * Handle premature socket errors.
+ *
+ * @private
+ */
+function socketOnError() {
+  this.destroy();
+}
+
+/**
+ * Close the connection when preconditions are not fulfilled.
+ *
+ * @param {(net.Socket|tls.Socket)} socket The socket of the upgrade request
+ * @param {Number} code The HTTP response status code
+ * @param {String} [message] The HTTP response body
+ * @param {Object} [headers] Additional HTTP response headers
+ * @private
+ */
+function abortHandshake(socket, code, message, headers) {
+  if (socket.writable) {
+    message = message || http.STATUS_CODES[code];
+    headers = {
+      Connection: 'close',
+      'Content-Type': 'text/html',
+      'Content-Length': Buffer.byteLength(message),
+      ...headers
+    };
+
+    socket.write(
+      `HTTP/1.1 ${code} ${http.STATUS_CODES[code]}\r\n` +
+        Object.keys(headers)
+          .map((h) => `${h}: ${headers[h]}`)
+          .join('\r\n') +
+        '\r\n\r\n' +
+        message
+    );
+  }
+
+  socket.removeListener('error', socketOnError);
+  socket.destroy();
+}
+
+/**
+ * Remove whitespace characters from both ends of a string.
+ *
+ * @param {String} str The string
+ * @return {String} A new string representing `str` stripped of whitespace
+ *     characters from both its beginning and end
+ * @private
+ */
+function trim(str) {
+  return str.trim();
+}

engine/ds-screencast/node_modules/chrome-remote-interface/node_modules/ws/package.json

@@ -0,0 +1,56 @@
+{
+  "name": "ws",
+  "version": "7.5.10",
+  "description": "Simple to use, blazing fast and thoroughly tested websocket client and server for Node.js",
+  "keywords": [
+    "HyBi",
+    "Push",
+    "RFC-6455",
+    "WebSocket",
+    "WebSockets",
+    "real-time"
+  ],
+  "homepage": "https://github.com/websockets/ws",
+  "bugs": "https://github.com/websockets/ws/issues",
+  "repository": "websockets/ws",
+  "author": "Einar Otto Stangvik <einaros@gmail.com> (http://2x.io)",
+  "license": "MIT",
+  "main": "index.js",
+  "browser": "browser.js",
+  "engines": {
+    "node": ">=8.3.0"
+  },
+  "files": [
+    "browser.js",
+    "index.js",
+    "lib/*.js"
+  ],
+  "scripts": {
+    "test": "nyc --reporter=lcov --reporter=text mocha --throw-deprecation test/*.test.js",
+    "integration": "mocha --throw-deprecation test/*.integration.js",
+    "lint": "eslint --ignore-path .gitignore . && prettier --check --ignore-path .gitignore \"**/*.{json,md,yaml,yml}\""
+  },
+  "peerDependencies": {
+    "bufferutil": "^4.0.1",
+    "utf-8-validate": "^5.0.2"
+  },
+  "peerDependenciesMeta": {
+    "bufferutil": {
+      "optional": true
+    },
+    "utf-8-validate": {
+      "optional": true
+    }
+  },
+  "devDependencies": {
+    "benchmark": "^2.1.4",
+    "bufferutil": "^4.0.1",
+    "eslint": "^7.2.0",
+    "eslint-config-prettier": "^8.1.0",
+    "eslint-plugin-prettier": "^4.0.0",
+    "mocha": "^7.0.0",
+    "nyc": "^15.0.0",
+    "prettier": "^2.0.5",
+    "utf-8-validate": "^5.0.2"
+  }
+}

engine/ds-screencast/node_modules/chrome-remote-interface/package.json

@@ -0,0 +1,64 @@
+{
+    "name": "chrome-remote-interface",
+    "author": "Andrea Cardaci <cyrus.and@gmail.com>",
+    "license": "MIT",
+    "contributors": [
+        "Andrey Sidorov <sidoares@yandex.ru>",
+        "Greg Cochard <greg@gregcochard.com>"
+    ],
+    "description": "Chrome Debugging Protocol interface",
+    "keywords": [
+        "chrome",
+        "debug",
+        "protocol",
+        "remote",
+        "interface"
+    ],
+    "homepage": "https://github.com/cyrus-and/chrome-remote-interface",
+    "version": "0.34.0",
+    "repository": {
+        "type": "git",
+        "url": "git://github.com/cyrus-and/chrome-remote-interface.git"
+    },
+    "bugs": {
+        "url": "http://github.com/cyrus-and/chrome-remote-interface/issues"
+    },
+    "engine-strict": {
+        "node": ">=8"
+    },
+    "dependencies": {
+        "commander": "2.11.x",
+        "ws": "^7.2.0"
+    },
+    "files": [
+        "lib",
+        "bin",
+        "index.js",
+        "chrome-remote-interface.js",
+        "webpack.config.js"
+    ],
+    "bin": {
+        "chrome-remote-interface": "bin/client.js"
+    },
+    "main": "index.js",
+    "browser": "chrome-remote-interface.js",
+    "devDependencies": {
+        "babel-core": "^6.26.3",
+        "babel-loader": "8.x.x",
+        "babel-polyfill": "^6.26.0",
+        "babel-preset-env": "^0.0.0",
+        "eslint": "^8.8.0",
+        "json-loader": "^0.5.4",
+        "mocha": "^11.1.0",
+        "process": "^0.11.10",
+        "url": "^0.11.0",
+        "util": "^0.12.4",
+        "webpack": "^5.39.0",
+        "webpack-cli": "^4.7.2"
+    },
+    "scripts": {
+        "test": "./scripts/run-tests.sh",
+        "webpack": "webpack",
+        "prepare": "webpack"
+    }
+}

engine/ds-screencast/node_modules/chrome-remote-interface/webpack.config.js

@@ -0,0 +1,48 @@
+'use strict';
+
+const TerserPlugin = require('terser-webpack-plugin');
+const webpack = require('webpack');
+
+function criWrapper(_, options, callback) {
+    window.criRequest(options, callback); // eslint-disable-line no-undef
+}
+
+module.exports = {
+    mode: 'production',
+    resolve: {
+        fallback: {
+            'util': require.resolve('util/'),
+            'url': require.resolve('url/'),
+            'http': false,
+            'https': false,
+            'dns': false
+        },
+        alias: {
+            'ws': './websocket-wrapper.js'
+        }
+    },
+    externals: [
+        {
+            './external-request.js': `var (${criWrapper})`
+        }
+    ],
+    plugins: [
+        new webpack.ProvidePlugin({
+            process: 'process/browser',
+        }),
+    ],
+    optimization: {
+        minimizer: [
+            new TerserPlugin({
+                extractComments: false,
+            })
+        ],
+    },
+    entry: ['babel-polyfill', './index.js'],
+    output: {
+        path: __dirname,
+        filename: 'chrome-remote-interface.js',
+        libraryTarget: process.env.TARGET || 'commonjs2',
+        library: 'CDP'
+    }
+};

engine/ds-screencast/node_modules/commander/History.md

@@ -0,0 +1,298 @@
+
+2.11.0 / 2017-07-03
+==================
+
+  * Fix help section order and padding (#652)
+  * feature: support for signals to subcommands (#632)
+  * Fixed #37, --help should not display first (#447)
+  * Fix translation errors. (#570)
+  * Add package-lock.json
+  * Remove engines
+  * Upgrade package version
+  * Prefix events to prevent conflicts between commands and options (#494)
+  * Removing dependency on graceful-readlink
+  * Support setting name in #name function and make it chainable
+  * Add .vscode directory to .gitignore (Visual Studio Code metadata)
+  * Updated link to ruby commander in readme files
+
+2.10.0 / 2017-06-19
+==================
+
+  * Update .travis.yml. drop support for older node.js versions.
+  * Fix require arguments in README.md
+  * On SemVer you do not start from 0.0.1
+  * Add missing semi colon in readme
+  * Add save param to npm install
+  * node v6 travis test
+  * Update Readme_zh-CN.md
+  * Allow literal '--' to be passed-through as an argument
+  * Test subcommand alias help
+  * link build badge to master branch
+  * Support the alias of Git style sub-command
+  * added keyword commander for better search result on npm
+  * Fix Sub-Subcommands
+  * test node.js stable
+  * Fixes TypeError when a command has an option called `--description`
+  * Update README.md to make it beginner friendly and elaborate on the difference between angled and square brackets.
+  * Add chinese Readme file
+
+2.9.0 / 2015-10-13
+==================
+
+  * Add option `isDefault` to set default subcommand #415 @Qix-
+  * Add callback to allow filtering or post-processing of help text #434 @djulien
+  * Fix `undefined` text in help information close #414 #416 @zhiyelee
+
+2.8.1 / 2015-04-22
+==================
+
+ * Back out `support multiline description` Close #396 #397
+
+2.8.0 / 2015-04-07
+==================
+
+  * Add `process.execArg` support, execution args like `--harmony` will be passed to sub-commands #387 @DigitalIO @zhiyelee
+  * Fix bug in Git-style sub-commands #372 @zhiyelee
+  * Allow commands to be hidden from help #383 @tonylukasavage
+  * When git-style sub-commands are in use, yet none are called, display help #382 @claylo
+  * Add ability to specify arguments syntax for top-level command #258 @rrthomas
+  * Support multiline descriptions #208 @zxqfox
+
+2.7.1 / 2015-03-11
+==================
+
+ * Revert #347 (fix collisions when option and first arg have same name) which causes a bug in #367.
+
+2.7.0 / 2015-03-09
+==================
+
+ * Fix git-style bug when installed globally. Close #335 #349 @zhiyelee
+ * Fix collisions when option and first arg have same name. Close #346 #347 @tonylukasavage
+ * Add support for camelCase on `opts()`. Close #353  @nkzawa
+ * Add node.js 0.12 and io.js to travis.yml
+ * Allow RegEx options. #337 @palanik
+ * Fixes exit code when sub-command failing.  Close #260 #332 @pirelenito
+ * git-style `bin` files in $PATH make sense. Close #196 #327  @zhiyelee
+
+2.6.0 / 2014-12-30
+==================
+
+  * added `Command#allowUnknownOption` method. Close #138 #318 @doozr @zhiyelee
+  * Add application description to the help msg. Close #112 @dalssoft
+
+2.5.1 / 2014-12-15
+==================
+
+  * fixed two bugs incurred by variadic arguments. Close #291 @Quentin01 #302 @zhiyelee
+
+2.5.0 / 2014-10-24
+==================
+
+ * add support for variadic arguments. Closes #277 @whitlockjc
+
+2.4.0 / 2014-10-17
+==================
+
+ * fixed a bug on executing the coercion function of subcommands option. Closes #270
+ * added `Command.prototype.name` to retrieve command name. Closes #264 #266 @tonylukasavage
+ * added `Command.prototype.opts` to retrieve all the options as a simple object of key-value pairs. Closes #262 @tonylukasavage
+ * fixed a bug on subcommand name. Closes #248 @jonathandelgado
+ * fixed function normalize doesn’t honor option terminator. Closes #216 @abbr
+
+2.3.0 / 2014-07-16
+==================
+
+ * add command alias'. Closes PR #210
+ * fix: Typos. Closes #99
+ * fix: Unused fs module. Closes #217
+
+2.2.0 / 2014-03-29
+==================
+
+ * add passing of previous option value
+ * fix: support subcommands on windows. Closes #142
+ * Now the defaultValue passed as the second argument of the coercion function.
+
+2.1.0 / 2013-11-21
+==================
+
+ * add: allow cflag style option params, unit test, fixes #174
+
+2.0.0 / 2013-07-18
+==================
+
+ * remove input methods (.prompt, .confirm, etc)
+
+1.3.2 / 2013-07-18
+==================
+
+ * add support for sub-commands to co-exist with the original command
+
+1.3.1 / 2013-07-18
+==================
+
+ * add quick .runningCommand hack so you can opt-out of other logic when running a sub command
+
+1.3.0 / 2013-07-09
+==================
+
+ * add EACCES error handling
+ * fix sub-command --help
+
+1.2.0 / 2013-06-13
+==================
+
+ * allow "-" hyphen as an option argument
+ * support for RegExp coercion
+
+1.1.1 / 2012-11-20
+==================
+
+  * add more sub-command padding
+  * fix .usage() when args are present. Closes #106
+
+1.1.0 / 2012-11-16
+==================
+
+  * add git-style executable subcommand support. Closes #94
+
+1.0.5 / 2012-10-09
+==================
+
+  * fix `--name` clobbering. Closes #92
+  * fix examples/help. Closes #89
+
+1.0.4 / 2012-09-03
+==================
+
+  * add `outputHelp()` method.
+
+1.0.3 / 2012-08-30
+==================
+
+  * remove invalid .version() defaulting
+
+1.0.2 / 2012-08-24
+==================
+
+  * add `--foo=bar` support [arv]
+  * fix password on node 0.8.8. Make backward compatible with 0.6 [focusaurus]
+
+1.0.1 / 2012-08-03
+==================
+
+  * fix issue #56
+  * fix tty.setRawMode(mode) was moved to tty.ReadStream#setRawMode() (i.e. process.stdin.setRawMode())
+
+1.0.0 / 2012-07-05
+==================
+
+  * add support for optional option descriptions
+  * add defaulting of `.version()` to package.json's version
+
+0.6.1 / 2012-06-01
+==================
+
+  * Added: append (yes or no) on confirmation
+  * Added: allow node.js v0.7.x
+
+0.6.0 / 2012-04-10
+==================
+
+  * Added `.prompt(obj, callback)` support. Closes #49
+  * Added default support to .choose(). Closes #41
+  * Fixed the choice example
+
+0.5.1 / 2011-12-20
+==================
+
+  * Fixed `password()` for recent nodes. Closes #36
+
+0.5.0 / 2011-12-04
+==================
+
+  * Added sub-command option support [itay]
+
+0.4.3 / 2011-12-04
+==================
+
+  * Fixed custom help ordering. Closes #32
+
+0.4.2 / 2011-11-24
+==================
+
+  * Added travis support
+  * Fixed: line-buffered input automatically trimmed. Closes #31
+
+0.4.1 / 2011-11-18
+==================
+
+  * Removed listening for "close" on --help
+
+0.4.0 / 2011-11-15
+==================
+
+  * Added support for `--`. Closes #24
+
+0.3.3 / 2011-11-14
+==================
+
+  * Fixed: wait for close event when writing help info [Jerry Hamlet]
+
+0.3.2 / 2011-11-01
+==================
+
+  * Fixed long flag definitions with values [felixge]
+
+0.3.1 / 2011-10-31
+==================
+
+  * Changed `--version` short flag to `-V` from `-v`
+  * Changed `.version()` so it's configurable [felixge]
+
+0.3.0 / 2011-10-31
+==================
+
+  * Added support for long flags only. Closes #18
+
+0.2.1 / 2011-10-24
+==================
+
+  * "node": ">= 0.4.x < 0.7.0". Closes #20
+
+0.2.0 / 2011-09-26
+==================
+
+  * Allow for defaults that are not just boolean. Default peassignment only occurs for --no-*, optional, and required arguments. [Jim Isaacs]
+
+0.1.0 / 2011-08-24
+==================
+
+  * Added support for custom `--help` output
+
+0.0.5 / 2011-08-18
+==================
+
+  * Changed: when the user enters nothing prompt for password again
+  * Fixed issue with passwords beginning with numbers [NuckChorris]
+
+0.0.4 / 2011-08-15
+==================
+
+  * Fixed `Commander#args`
+
+0.0.3 / 2011-08-15
+==================
+
+  * Added default option value support
+
+0.0.2 / 2011-08-15
+==================
+
+  * Added mask support to `Command#password(str[, mask], fn)`
+  * Added `Command#password(str, fn)`
+
+0.0.1 / 2010-01-03
+==================
+
+  * Initial release

engine/ds-screencast/node_modules/commander/LICENSE

@@ -0,0 +1,22 @@
+(The MIT License)
+
+Copyright (c) 2011 TJ Holowaychuk <tj@vision-media.ca>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

engine/ds-screencast/node_modules/commander/Readme.md

@@ -0,0 +1,351 @@
+# Commander.js
+
+
+[![Build Status](https://api.travis-ci.org/tj/commander.js.svg?branch=master)](http://travis-ci.org/tj/commander.js)
+[![NPM Version](http://img.shields.io/npm/v/commander.svg?style=flat)](https://www.npmjs.org/package/commander)
+[![NPM Downloads](https://img.shields.io/npm/dm/commander.svg?style=flat)](https://www.npmjs.org/package/commander)
+[![Join the chat at https://gitter.im/tj/commander.js](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/tj/commander.js?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
+
+  The complete solution for [node.js](http://nodejs.org) command-line interfaces, inspired by Ruby's [commander](https://github.com/commander-rb/commander).  
+  [API documentation](http://tj.github.com/commander.js/)
+
+
+## Installation
+
+    $ npm install commander --save
+
+## Option parsing
+
+ Options with commander are defined with the `.option()` method, also serving as documentation for the options. The example below parses args and options from `process.argv`, leaving remaining args as the `program.args` array which were not consumed by options.
+
+```js
+#!/usr/bin/env node
+
+/**
+ * Module dependencies.
+ */
+
+var program = require('commander');
+
+program
+  .version('0.1.0')
+  .option('-p, --peppers', 'Add peppers')
+  .option('-P, --pineapple', 'Add pineapple')
+  .option('-b, --bbq-sauce', 'Add bbq sauce')
+  .option('-c, --cheese [type]', 'Add the specified type of cheese [marble]', 'marble')
+  .parse(process.argv);
+
+console.log('you ordered a pizza with:');
+if (program.peppers) console.log('  - peppers');
+if (program.pineapple) console.log('  - pineapple');
+if (program.bbqSauce) console.log('  - bbq');
+console.log('  - %s cheese', program.cheese);
+```
+
+ Short flags may be passed as a single arg, for example `-abc` is equivalent to `-a -b -c`. Multi-word options such as "--template-engine" are camel-cased, becoming `program.templateEngine` etc.
+
+
+## Coercion
+
+```js
+function range(val) {
+  return val.split('..').map(Number);
+}
+
+function list(val) {
+  return val.split(',');
+}
+
+function collect(val, memo) {
+  memo.push(val);
+  return memo;
+}
+
+function increaseVerbosity(v, total) {
+  return total + 1;
+}
+
+program
+  .version('0.1.0')
+  .usage('[options] <file ...>')
+  .option('-i, --integer <n>', 'An integer argument', parseInt)
+  .option('-f, --float <n>', 'A float argument', parseFloat)
+  .option('-r, --range <a>..<b>', 'A range', range)
+  .option('-l, --list <items>', 'A list', list)
+  .option('-o, --optional [value]', 'An optional value')
+  .option('-c, --collect [value]', 'A repeatable value', collect, [])
+  .option('-v, --verbose', 'A value that can be increased', increaseVerbosity, 0)
+  .parse(process.argv);
+
+console.log(' int: %j', program.integer);
+console.log(' float: %j', program.float);
+console.log(' optional: %j', program.optional);
+program.range = program.range || [];
+console.log(' range: %j..%j', program.range[0], program.range[1]);
+console.log(' list: %j', program.list);
+console.log(' collect: %j', program.collect);
+console.log(' verbosity: %j', program.verbose);
+console.log(' args: %j', program.args);
+```
+
+## Regular Expression
+```js
+program
+  .version('0.1.0')
+  .option('-s --size <size>', 'Pizza size', /^(large|medium|small)$/i, 'medium')
+  .option('-d --drink [drink]', 'Drink', /^(coke|pepsi|izze)$/i)
+  .parse(process.argv);
+  
+console.log(' size: %j', program.size);
+console.log(' drink: %j', program.drink);
+```
+
+## Variadic arguments
+
+ The last argument of a command can be variadic, and only the last argument.  To make an argument variadic you have to
+ append `...` to the argument name.  Here is an example:
+
+```js
+#!/usr/bin/env node
+
+/**
+ * Module dependencies.
+ */
+
+var program = require('commander');
+
+program
+  .version('0.1.0')
+  .command('rmdir <dir> [otherDirs...]')
+  .action(function (dir, otherDirs) {
+    console.log('rmdir %s', dir);
+    if (otherDirs) {
+      otherDirs.forEach(function (oDir) {
+        console.log('rmdir %s', oDir);
+      });
+    }
+  });
+
+program.parse(process.argv);
+```
+
+ An `Array` is used for the value of a variadic argument.  This applies to `program.args` as well as the argument passed
+ to your action as demonstrated above.
+
+## Specify the argument syntax
+
+```js
+#!/usr/bin/env node
+
+var program = require('commander');
+
+program
+  .version('0.1.0')
+  .arguments('<cmd> [env]')
+  .action(function (cmd, env) {
+     cmdValue = cmd;
+     envValue = env;
+  });
+
+program.parse(process.argv);
+
+if (typeof cmdValue === 'undefined') {
+   console.error('no command given!');
+   process.exit(1);
+}
+console.log('command:', cmdValue);
+console.log('environment:', envValue || "no environment given");
+```
+Angled brackets (e.g. `<cmd>`) indicate required input. Square brackets (e.g. `[env]`) indicate optional input.
+
+## Git-style sub-commands
+
+```js
+// file: ./examples/pm
+var program = require('commander');
+
+program
+  .version('0.1.0')
+  .command('install [name]', 'install one or more packages')
+  .command('search [query]', 'search with optional query')
+  .command('list', 'list packages installed', {isDefault: true})
+  .parse(process.argv);
+```
+
+When `.command()` is invoked with a description argument, no `.action(callback)` should be called to handle sub-commands, otherwise there will be an error. This tells commander that you're going to use separate executables for sub-commands, much like `git(1)` and other popular tools.  
+The commander will try to search the executables in the directory of the entry script (like `./examples/pm`) with the name `program-command`, like `pm-install`, `pm-search`.
+
+Options can be passed with the call to `.command()`. Specifying `true` for `opts.noHelp` will remove the option from the generated help output. Specifying `true` for `opts.isDefault` will run the subcommand if no other subcommand is specified.
+
+If the program is designed to be installed globally, make sure the executables have proper modes, like `755`.
+
+### `--harmony`
+
+You can enable `--harmony` option in two ways:
+* Use `#! /usr/bin/env node --harmony` in the sub-commands scripts. Note some os version don’t support this pattern.
+* Use the `--harmony` option when call the command, like `node --harmony examples/pm publish`. The `--harmony` option will be preserved when spawning sub-command process.
+
+## Automated --help
+
+ The help information is auto-generated based on the information commander already knows about your program, so the following `--help` info is for free:
+
+```  
+ $ ./examples/pizza --help
+
+   Usage: pizza [options]
+
+   An application for pizzas ordering
+
+   Options:
+
+     -h, --help           output usage information
+     -V, --version        output the version number
+     -p, --peppers        Add peppers
+     -P, --pineapple      Add pineapple
+     -b, --bbq            Add bbq sauce
+     -c, --cheese <type>  Add the specified type of cheese [marble]
+     -C, --no-cheese      You do not want any cheese
+
+```
+
+## Custom help
+
+ You can display arbitrary `-h, --help` information
+ by listening for "--help". Commander will automatically
+ exit once you are done so that the remainder of your program
+ does not execute causing undesired behaviours, for example
+ in the following executable "stuff" will not output when
+ `--help` is used.
+
+```js
+#!/usr/bin/env node
+
+/**
+ * Module dependencies.
+ */
+
+var program = require('commander');
+
+program
+  .version('0.1.0')
+  .option('-f, --foo', 'enable some foo')
+  .option('-b, --bar', 'enable some bar')
+  .option('-B, --baz', 'enable some baz');
+
+// must be before .parse() since
+// node's emit() is immediate
+
+program.on('--help', function(){
+  console.log('  Examples:');
+  console.log('');
+  console.log('    $ custom-help --help');
+  console.log('    $ custom-help -h');
+  console.log('');
+});
+
+program.parse(process.argv);
+
+console.log('stuff');
+```
+
+Yields the following help output when `node script-name.js -h` or `node script-name.js --help` are run:
+
+```
+
+Usage: custom-help [options]
+
+Options:
+
+  -h, --help     output usage information
+  -V, --version  output the version number
+  -f, --foo      enable some foo
+  -b, --bar      enable some bar
+  -B, --baz      enable some baz
+
+Examples:
+
+  $ custom-help --help
+  $ custom-help -h
+
+```
+
+## .outputHelp(cb)
+
+Output help information without exiting.
+Optional callback cb allows post-processing of help text before it is displayed.
+
+If you want to display help by default (e.g. if no command was provided), you can use something like:
+
+```js
+var program = require('commander');
+var colors = require('colors');
+
+program
+  .version('0.1.0')
+  .command('getstream [url]', 'get stream URL')
+  .parse(process.argv);
+
+  if (!process.argv.slice(2).length) {
+    program.outputHelp(make_red);
+  }
+
+function make_red(txt) {
+  return colors.red(txt); //display the help text in red on the console
+}
+```
+
+## .help(cb)
+
+  Output help information and exit immediately.
+  Optional callback cb allows post-processing of help text before it is displayed.
+
+## Examples
+
+```js
+var program = require('commander');
+
+program
+  .version('0.1.0')
+  .option('-C, --chdir <path>', 'change the working directory')
+  .option('-c, --config <path>', 'set config path. defaults to ./deploy.conf')
+  .option('-T, --no-tests', 'ignore test hook');
+
+program
+  .command('setup [env]')
+  .description('run setup commands for all envs')
+  .option("-s, --setup_mode [mode]", "Which setup mode to use")
+  .action(function(env, options){
+    var mode = options.setup_mode || "normal";
+    env = env || 'all';
+    console.log('setup for %s env(s) with %s mode', env, mode);
+  });
+
+program
+  .command('exec <cmd>')
+  .alias('ex')
+  .description('execute the given remote cmd')
+  .option("-e, --exec_mode <mode>", "Which exec mode to use")
+  .action(function(cmd, options){
+    console.log('exec "%s" using %s mode', cmd, options.exec_mode);
+  }).on('--help', function() {
+    console.log('  Examples:');
+    console.log();
+    console.log('    $ deploy exec sequential');
+    console.log('    $ deploy exec async');
+    console.log();
+  });
+
+program
+  .command('*')
+  .action(function(env){
+    console.log('deploying "%s"', env);
+  });
+
+program.parse(process.argv);
+```
+
+More Demos can be found in the [examples](https://github.com/tj/commander.js/tree/master/examples) directory.
+
+## License
+
+MIT

engine/ds-screencast/node_modules/commander/package.json

@@ -0,0 +1,29 @@
+{
+  "name": "commander",
+  "version": "2.11.0",
+  "description": "the complete solution for node.js command-line programs",
+  "keywords": [
+    "commander",
+    "command",
+    "option",
+    "parser"
+  ],
+  "author": "TJ Holowaychuk <tj@vision-media.ca>",
+  "license": "MIT",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/tj/commander.js.git"
+  },
+  "devDependencies": {
+    "should": "^11.2.1",
+    "sinon": "^2.3.5"
+  },
+  "scripts": {
+    "test": "make test"
+  },
+  "main": "index",
+  "files": [
+    "index.js"
+  ],
+  "dependencies": {}
+}

engine/ds-screencast/node_modules/ws/LICENSE

@@ -0,0 +1,20 @@
+Copyright (c) 2011 Einar Otto Stangvik <einaros@gmail.com>
+Copyright (c) 2013 Arnout Kazemier and contributors
+Copyright (c) 2016 Luigi Pinca and contributors
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

engine/ds-screencast/node_modules/ws/README.md

@@ -0,0 +1,548 @@
+# ws: a Node.js WebSocket library
+
+[![Version npm](https://img.shields.io/npm/v/ws.svg?logo=npm)](https://www.npmjs.com/package/ws)
+[![CI](https://img.shields.io/github/actions/workflow/status/websockets/ws/ci.yml?branch=master&label=CI&logo=github)](https://github.com/websockets/ws/actions?query=workflow%3ACI+branch%3Amaster)
+[![Coverage Status](https://img.shields.io/coveralls/websockets/ws/master.svg?logo=coveralls)](https://coveralls.io/github/websockets/ws)
+
+ws is a simple to use, blazing fast, and thoroughly tested WebSocket client and
+server implementation.
+
+Passes the quite extensive Autobahn test suite: [server][server-report],
+[client][client-report].
+
+**Note**: This module does not work in the browser. The client in the docs is a
+reference to a backend with the role of a client in the WebSocket communication.
+Browser clients must use the native
+[`WebSocket`](https://developer.mozilla.org/en-US/docs/Web/API/WebSocket)
+object. To make the same code work seamlessly on Node.js and the browser, you
+can use one of the many wrappers available on npm, like
+[isomorphic-ws](https://github.com/heineiuo/isomorphic-ws).
+
+## Table of Contents
+
+- [Protocol support](#protocol-support)
+- [Installing](#installing)
+  - [Opt-in for performance](#opt-in-for-performance)
+    - [Legacy opt-in for performance](#legacy-opt-in-for-performance)
+- [API docs](#api-docs)
+- [WebSocket compression](#websocket-compression)
+- [Usage examples](#usage-examples)
+  - [Sending and receiving text data](#sending-and-receiving-text-data)
+  - [Sending binary data](#sending-binary-data)
+  - [Simple server](#simple-server)
+  - [External HTTP/S server](#external-https-server)
+  - [Multiple servers sharing a single HTTP/S server](#multiple-servers-sharing-a-single-https-server)
+  - [Client authentication](#client-authentication)
+  - [Server broadcast](#server-broadcast)
+  - [Round-trip time](#round-trip-time)
+  - [Use the Node.js streams API](#use-the-nodejs-streams-api)
+  - [Other examples](#other-examples)
+- [FAQ](#faq)
+  - [How to get the IP address of the client?](#how-to-get-the-ip-address-of-the-client)
+  - [How to detect and close broken connections?](#how-to-detect-and-close-broken-connections)
+  - [How to connect via a proxy?](#how-to-connect-via-a-proxy)
+- [Changelog](#changelog)
+- [License](#license)
+
+## Protocol support
+
+- **HyBi drafts 07-12** (Use the option `protocolVersion: 8`)
+- **HyBi drafts 13-17** (Current default, alternatively option
+  `protocolVersion: 13`)
+
+## Installing
+
+```
+npm install ws
+```
+
+### Opt-in for performance
+
+[bufferutil][] is an optional module that can be installed alongside the ws
+module:
+
+```
+npm install --save-optional bufferutil
+```
+
+This is a binary addon that improves the performance of certain operations such
+as masking and unmasking the data payload of the WebSocket frames. Prebuilt
+binaries are available for the most popular platforms, so you don't necessarily
+need to have a C++ compiler installed on your machine.
+
+To force ws to not use bufferutil, use the
+[`WS_NO_BUFFER_UTIL`](./doc/ws.md#ws_no_buffer_util) environment variable. This
+can be useful to enhance security in systems where a user can put a package in
+the package search path of an application of another user, due to how the
+Node.js resolver algorithm works.
+
+#### Legacy opt-in for performance
+
+If you are running on an old version of Node.js (prior to v18.14.0), ws also
+supports the [utf-8-validate][] module:
+
+```
+npm install --save-optional utf-8-validate
+```
+
+This contains a binary polyfill for [`buffer.isUtf8()`][].
+
+To force ws not to use utf-8-validate, use the
+[`WS_NO_UTF_8_VALIDATE`](./doc/ws.md#ws_no_utf_8_validate) environment variable.
+
+## API docs
+
+See [`/doc/ws.md`](./doc/ws.md) for Node.js-like documentation of ws classes and
+utility functions.
+
+## WebSocket compression
+
+ws supports the [permessage-deflate extension][permessage-deflate] which enables
+the client and server to negotiate a compression algorithm and its parameters,
+and then selectively apply it to the data payloads of each WebSocket message.
+
+The extension is disabled by default on the server and enabled by default on the
+client. It adds a significant overhead in terms of performance and memory
+consumption so we suggest to enable it only if it is really needed.
+
+Note that Node.js has a variety of issues with high-performance compression,
+where increased concurrency, especially on Linux, can lead to [catastrophic
+memory fragmentation][node-zlib-bug] and slow performance. If you intend to use
+permessage-deflate in production, it is worthwhile to set up a test
+representative of your workload and ensure Node.js/zlib will handle it with
+acceptable performance and memory usage.
+
+Tuning of permessage-deflate can be done via the options defined below. You can
+also use `zlibDeflateOptions` and `zlibInflateOptions`, which is passed directly
+into the creation of [raw deflate/inflate streams][node-zlib-deflaterawdocs].
+
+See [the docs][ws-server-options] for more options.
+
+```js
+import WebSocket, { WebSocketServer } from 'ws';
+
+const wss = new WebSocketServer({
+  port: 8080,
+  perMessageDeflate: {
+    zlibDeflateOptions: {
+      // See zlib defaults.
+      chunkSize: 1024,
+      memLevel: 7,
+      level: 3
+    },
+    zlibInflateOptions: {
+      chunkSize: 10 * 1024
+    },
+    // Other options settable:
+    clientNoContextTakeover: true, // Defaults to negotiated value.
+    serverNoContextTakeover: true, // Defaults to negotiated value.
+    serverMaxWindowBits: 10, // Defaults to negotiated value.
+    // Below options specified as default values.
+    concurrencyLimit: 10, // Limits zlib concurrency for perf.
+    threshold: 1024 // Size (in bytes) below which messages
+    // should not be compressed if context takeover is disabled.
+  }
+});
+```
+
+The client will only use the extension if it is supported and enabled on the
+server. To always disable the extension on the client, set the
+`perMessageDeflate` option to `false`.
+
+```js
+import WebSocket from 'ws';
+
+const ws = new WebSocket('ws://www.host.com/path', {
+  perMessageDeflate: false
+});
+```
+
+## Usage examples
+
+### Sending and receiving text data
+
+```js
+import WebSocket from 'ws';
+
+const ws = new WebSocket('ws://www.host.com/path');
+
+ws.on('error', console.error);
+
+ws.on('open', function open() {
+  ws.send('something');
+});
+
+ws.on('message', function message(data) {
+  console.log('received: %s', data);
+});
+```
+
+### Sending binary data
+
+```js
+import WebSocket from 'ws';
+
+const ws = new WebSocket('ws://www.host.com/path');
+
+ws.on('error', console.error);
+
+ws.on('open', function open() {
+  const array = new Float32Array(5);
+
+  for (var i = 0; i < array.length; ++i) {
+    array[i] = i / 2;
+  }
+
+  ws.send(array);
+});
+```
+
+### Simple server
+
+```js
+import { WebSocketServer } from 'ws';
+
+const wss = new WebSocketServer({ port: 8080 });
+
+wss.on('connection', function connection(ws) {
+  ws.on('error', console.error);
+
+  ws.on('message', function message(data) {
+    console.log('received: %s', data);
+  });
+
+  ws.send('something');
+});
+```
+
+### External HTTP/S server
+
+```js
+import { createServer } from 'https';
+import { readFileSync } from 'fs';
+import { WebSocketServer } from 'ws';
+
+const server = createServer({
+  cert: readFileSync('/path/to/cert.pem'),
+  key: readFileSync('/path/to/key.pem')
+});
+const wss = new WebSocketServer({ server });
+
+wss.on('connection', function connection(ws) {
+  ws.on('error', console.error);
+
+  ws.on('message', function message(data) {
+    console.log('received: %s', data);
+  });
+
+  ws.send('something');
+});
+
+server.listen(8080);
+```
+
+### Multiple servers sharing a single HTTP/S server
+
+```js
+import { createServer } from 'http';
+import { WebSocketServer } from 'ws';
+
+const server = createServer();
+const wss1 = new WebSocketServer({ noServer: true });
+const wss2 = new WebSocketServer({ noServer: true });
+
+wss1.on('connection', function connection(ws) {
+  ws.on('error', console.error);
+
+  // ...
+});
+
+wss2.on('connection', function connection(ws) {
+  ws.on('error', console.error);
+
+  // ...
+});
+
+server.on('upgrade', function upgrade(request, socket, head) {
+  const { pathname } = new URL(request.url, 'wss://base.url');
+
+  if (pathname === '/foo') {
+    wss1.handleUpgrade(request, socket, head, function done(ws) {
+      wss1.emit('connection', ws, request);
+    });
+  } else if (pathname === '/bar') {
+    wss2.handleUpgrade(request, socket, head, function done(ws) {
+      wss2.emit('connection', ws, request);
+    });
+  } else {
+    socket.destroy();
+  }
+});
+
+server.listen(8080);
+```
+
+### Client authentication
+
+```js
+import { createServer } from 'http';
+import { WebSocketServer } from 'ws';
+
+function onSocketError(err) {
+  console.error(err);
+}
+
+const server = createServer();
+const wss = new WebSocketServer({ noServer: true });
+
+wss.on('connection', function connection(ws, request, client) {
+  ws.on('error', console.error);
+
+  ws.on('message', function message(data) {
+    console.log(`Received message ${data} from user ${client}`);
+  });
+});
+
+server.on('upgrade', function upgrade(request, socket, head) {
+  socket.on('error', onSocketError);
+
+  // This function is not defined on purpose. Implement it with your own logic.
+  authenticate(request, function next(err, client) {
+    if (err || !client) {
+      socket.write('HTTP/1.1 401 Unauthorized\r\n\r\n');
+      socket.destroy();
+      return;
+    }
+
+    socket.removeListener('error', onSocketError);
+
+    wss.handleUpgrade(request, socket, head, function done(ws) {
+      wss.emit('connection', ws, request, client);
+    });
+  });
+});
+
+server.listen(8080);
+```
+
+Also see the provided [example][session-parse-example] using `express-session`.
+
+### Server broadcast
+
+A client WebSocket broadcasting to all connected WebSocket clients, including
+itself.
+
+```js
+import WebSocket, { WebSocketServer } from 'ws';
+
+const wss = new WebSocketServer({ port: 8080 });
+
+wss.on('connection', function connection(ws) {
+  ws.on('error', console.error);
+
+  ws.on('message', function message(data, isBinary) {
+    wss.clients.forEach(function each(client) {
+      if (client.readyState === WebSocket.OPEN) {
+        client.send(data, { binary: isBinary });
+      }
+    });
+  });
+});
+```
+
+A client WebSocket broadcasting to every other connected WebSocket clients,
+excluding itself.
+
+```js
+import WebSocket, { WebSocketServer } from 'ws';
+
+const wss = new WebSocketServer({ port: 8080 });
+
+wss.on('connection', function connection(ws) {
+  ws.on('error', console.error);
+
+  ws.on('message', function message(data, isBinary) {
+    wss.clients.forEach(function each(client) {
+      if (client !== ws && client.readyState === WebSocket.OPEN) {
+        client.send(data, { binary: isBinary });
+      }
+    });
+  });
+});
+```
+
+### Round-trip time
+
+```js
+import WebSocket from 'ws';
+
+const ws = new WebSocket('wss://websocket-echo.com/');
+
+ws.on('error', console.error);
+
+ws.on('open', function open() {
+  console.log('connected');
+  ws.send(Date.now());
+});
+
+ws.on('close', function close() {
+  console.log('disconnected');
+});
+
+ws.on('message', function message(data) {
+  console.log(`Round-trip time: ${Date.now() - data} ms`);
+
+  setTimeout(function timeout() {
+    ws.send(Date.now());
+  }, 500);
+});
+```
+
+### Use the Node.js streams API
+
+```js
+import WebSocket, { createWebSocketStream } from 'ws';
+
+const ws = new WebSocket('wss://websocket-echo.com/');
+
+const duplex = createWebSocketStream(ws, { encoding: 'utf8' });
+
+duplex.on('error', console.error);
+
+duplex.pipe(process.stdout);
+process.stdin.pipe(duplex);
+```
+
+### Other examples
+
+For a full example with a browser client communicating with a ws server, see the
+examples folder.
+
+Otherwise, see the test cases.
+
+## FAQ
+
+### How to get the IP address of the client?
+
+The remote IP address can be obtained from the raw socket.
+
+```js
+import { WebSocketServer } from 'ws';
+
+const wss = new WebSocketServer({ port: 8080 });
+
+wss.on('connection', function connection(ws, req) {
+  const ip = req.socket.remoteAddress;
+
+  ws.on('error', console.error);
+});
+```
+
+When the server runs behind a proxy like NGINX, the de-facto standard is to use
+the `X-Forwarded-For` header.
+
+```js
+wss.on('connection', function connection(ws, req) {
+  const ip = req.headers['x-forwarded-for'].split(',')[0].trim();
+
+  ws.on('error', console.error);
+});
+```
+
+### How to detect and close broken connections?
+
+Sometimes, the link between the server and the client can be interrupted in a
+way that keeps both the server and the client unaware of the broken state of the
+connection (e.g. when pulling the cord).
+
+In these cases, ping messages can be used as a means to verify that the remote
+endpoint is still responsive.
+
+```js
+import { WebSocketServer } from 'ws';
+
+function heartbeat() {
+  this.isAlive = true;
+}
+
+const wss = new WebSocketServer({ port: 8080 });
+
+wss.on('connection', function connection(ws) {
+  ws.isAlive = true;
+  ws.on('error', console.error);
+  ws.on('pong', heartbeat);
+});
+
+const interval = setInterval(function ping() {
+  wss.clients.forEach(function each(ws) {
+    if (ws.isAlive === false) return ws.terminate();
+
+    ws.isAlive = false;
+    ws.ping();
+  });
+}, 30000);
+
+wss.on('close', function close() {
+  clearInterval(interval);
+});
+```
+
+Pong messages are automatically sent in response to ping messages as required by
+the spec.
+
+Just like the server example above, your clients might as well lose connection
+without knowing it. You might want to add a ping listener on your clients to
+prevent that. A simple implementation would be:
+
+```js
+import WebSocket from 'ws';
+
+function heartbeat() {
+  clearTimeout(this.pingTimeout);
+
+  // Use `WebSocket#terminate()`, which immediately destroys the connection,
+  // instead of `WebSocket#close()`, which waits for the close timer.
+  // Delay should be equal to the interval at which your server
+  // sends out pings plus a conservative assumption of the latency.
+  this.pingTimeout = setTimeout(() => {
+    this.terminate();
+  }, 30000 + 1000);
+}
+
+const client = new WebSocket('wss://websocket-echo.com/');
+
+client.on('error', console.error);
+client.on('open', heartbeat);
+client.on('ping', heartbeat);
+client.on('close', function clear() {
+  clearTimeout(this.pingTimeout);
+});
+```
+
+### How to connect via a proxy?
+
+Use a custom `http.Agent` implementation like [https-proxy-agent][] or
+[socks-proxy-agent][].
+
+## Changelog
+
+We're using the GitHub [releases][changelog] for changelog entries.
+
+## License
+
+[MIT](LICENSE)
+
+[`buffer.isutf8()`]: https://nodejs.org/api/buffer.html#bufferisutf8input
+[bufferutil]: https://github.com/websockets/bufferutil
+[changelog]: https://github.com/websockets/ws/releases
+[client-report]: http://websockets.github.io/ws/autobahn/clients/
+[https-proxy-agent]: https://github.com/TooTallNate/node-https-proxy-agent
+[node-zlib-bug]: https://github.com/nodejs/node/issues/8871
+[node-zlib-deflaterawdocs]:
+  https://nodejs.org/api/zlib.html#zlib_zlib_createdeflateraw_options
+[permessage-deflate]: https://tools.ietf.org/html/rfc7692
+[server-report]: http://websockets.github.io/ws/autobahn/servers/
+[session-parse-example]: ./examples/express-session-parse
+[socks-proxy-agent]: https://github.com/TooTallNate/node-socks-proxy-agent
+[utf-8-validate]: https://github.com/websockets/utf-8-validate
+[ws-server-options]: ./doc/ws.md#new-websocketserveroptions-callback

engine/ds-screencast/node_modules/ws/browser.js

@@ -0,0 +1,8 @@
+'use strict';
+
+module.exports = function () {
+  throw new Error(
+    'ws does not work in the browser. Browser clients must use the native ' +
+      'WebSocket object'
+  );
+};

engine/ds-screencast/node_modules/ws/index.js

@@ -0,0 +1,13 @@
+'use strict';
+
+const WebSocket = require('./lib/websocket');
+
+WebSocket.createWebSocketStream = require('./lib/stream');
+WebSocket.Server = require('./lib/websocket-server');
+WebSocket.Receiver = require('./lib/receiver');
+WebSocket.Sender = require('./lib/sender');
+
+WebSocket.WebSocket = WebSocket;
+WebSocket.WebSocketServer = WebSocket.Server;
+
+module.exports = WebSocket;

engine/ds-screencast/node_modules/ws/lib/buffer-util.js

@@ -0,0 +1,131 @@
+'use strict';
+
+const { EMPTY_BUFFER } = require('./constants');
+
+const FastBuffer = Buffer[Symbol.species];
+
+/**
+ * Merges an array of buffers into a new buffer.
+ *
+ * @param {Buffer[]} list The array of buffers to concat
+ * @param {Number} totalLength The total length of buffers in the list
+ * @return {Buffer} The resulting buffer
+ * @public
+ */
+function concat(list, totalLength) {
+  if (list.length === 0) return EMPTY_BUFFER;
+  if (list.length === 1) return list[0];
+
+  const target = Buffer.allocUnsafe(totalLength);
+  let offset = 0;
+
+  for (let i = 0; i < list.length; i++) {
+    const buf = list[i];
+    target.set(buf, offset);
+    offset += buf.length;
+  }
+
+  if (offset < totalLength) {
+    return new FastBuffer(target.buffer, target.byteOffset, offset);
+  }
+
+  return target;
+}
+
+/**
+ * Masks a buffer using the given mask.
+ *
+ * @param {Buffer} source The buffer to mask
+ * @param {Buffer} mask The mask to use
+ * @param {Buffer} output The buffer where to store the result
+ * @param {Number} offset The offset at which to start writing
+ * @param {Number} length The number of bytes to mask.
+ * @public
+ */
+function _mask(source, mask, output, offset, length) {
+  for (let i = 0; i < length; i++) {
+    output[offset + i] = source[i] ^ mask[i & 3];
+  }
+}
+
+/**
+ * Unmasks a buffer using the given mask.
+ *
+ * @param {Buffer} buffer The buffer to unmask
+ * @param {Buffer} mask The mask to use
+ * @public
+ */
+function _unmask(buffer, mask) {
+  for (let i = 0; i < buffer.length; i++) {
+    buffer[i] ^= mask[i & 3];
+  }
+}
+
+/**
+ * Converts a buffer to an `ArrayBuffer`.
+ *
+ * @param {Buffer} buf The buffer to convert
+ * @return {ArrayBuffer} Converted buffer
+ * @public
+ */
+function toArrayBuffer(buf) {
+  if (buf.length === buf.buffer.byteLength) {
+    return buf.buffer;
+  }
+
+  return buf.buffer.slice(buf.byteOffset, buf.byteOffset + buf.length);
+}
+
+/**
+ * Converts `data` to a `Buffer`.
+ *
+ * @param {*} data The data to convert
+ * @return {Buffer} The buffer
+ * @throws {TypeError}
+ * @public
+ */
+function toBuffer(data) {
+  toBuffer.readOnly = true;
+
+  if (Buffer.isBuffer(data)) return data;
+
+  let buf;
+
+  if (data instanceof ArrayBuffer) {
+    buf = new FastBuffer(data);
+  } else if (ArrayBuffer.isView(data)) {
+    buf = new FastBuffer(data.buffer, data.byteOffset, data.byteLength);
+  } else {
+    buf = Buffer.from(data);
+    toBuffer.readOnly = false;
+  }
+
+  return buf;
+}
+
+module.exports = {
+  concat,
+  mask: _mask,
+  toArrayBuffer,
+  toBuffer,
+  unmask: _unmask
+};
+
+/* istanbul ignore else  */
+if (!process.env.WS_NO_BUFFER_UTIL) {
+  try {
+    const bufferUtil = require('bufferutil');
+
+    module.exports.mask = function (source, mask, output, offset, length) {
+      if (length < 48) _mask(source, mask, output, offset, length);
+      else bufferUtil.mask(source, mask, output, offset, length);
+    };
+
+    module.exports.unmask = function (buffer, mask) {
+      if (buffer.length < 32) _unmask(buffer, mask);
+      else bufferUtil.unmask(buffer, mask);
+    };
+  } catch (e) {
+    // Continue regardless of the error.
+  }
+}

engine/ds-screencast/node_modules/ws/lib/constants.js

@@ -0,0 +1,19 @@
+'use strict';
+
+const BINARY_TYPES = ['nodebuffer', 'arraybuffer', 'fragments'];
+const hasBlob = typeof Blob !== 'undefined';
+
+if (hasBlob) BINARY_TYPES.push('blob');
+
+module.exports = {
+  BINARY_TYPES,
+  CLOSE_TIMEOUT: 30000,
+  EMPTY_BUFFER: Buffer.alloc(0),
+  GUID: '258EAFA5-E914-47DA-95CA-C5AB0DC85B11',
+  hasBlob,
+  kForOnEventAttribute: Symbol('kIsForOnEventAttribute'),
+  kListener: Symbol('kListener'),
+  kStatusCode: Symbol('status-code'),
+  kWebSocket: Symbol('websocket'),
+  NOOP: () => {}
+};

engine/ds-screencast/node_modules/ws/lib/event-target.js

@@ -0,0 +1,292 @@
+'use strict';
+
+const { kForOnEventAttribute, kListener } = require('./constants');
+
+const kCode = Symbol('kCode');
+const kData = Symbol('kData');
+const kError = Symbol('kError');
+const kMessage = Symbol('kMessage');
+const kReason = Symbol('kReason');
+const kTarget = Symbol('kTarget');
+const kType = Symbol('kType');
+const kWasClean = Symbol('kWasClean');
+
+/**
+ * Class representing an event.
+ */
+class Event {
+  /**
+   * Create a new `Event`.
+   *
+   * @param {String} type The name of the event
+   * @throws {TypeError} If the `type` argument is not specified
+   */
+  constructor(type) {
+    this[kTarget] = null;
+    this[kType] = type;
+  }
+
+  /**
+   * @type {*}
+   */
+  get target() {
+    return this[kTarget];
+  }
+
+  /**
+   * @type {String}
+   */
+  get type() {
+    return this[kType];
+  }
+}
+
+Object.defineProperty(Event.prototype, 'target', { enumerable: true });
+Object.defineProperty(Event.prototype, 'type', { enumerable: true });
+
+/**
+ * Class representing a close event.
+ *
+ * @extends Event
+ */
+class CloseEvent extends Event {
+  /**
+   * Create a new `CloseEvent`.
+   *
+   * @param {String} type The name of the event
+   * @param {Object} [options] A dictionary object that allows for setting
+   *     attributes via object members of the same name
+   * @param {Number} [options.code=0] The status code explaining why the
+   *     connection was closed
+   * @param {String} [options.reason=''] A human-readable string explaining why
+   *     the connection was closed
+   * @param {Boolean} [options.wasClean=false] Indicates whether or not the
+   *     connection was cleanly closed
+   */
+  constructor(type, options = {}) {
+    super(type);
+
+    this[kCode] = options.code === undefined ? 0 : options.code;
+    this[kReason] = options.reason === undefined ? '' : options.reason;
+    this[kWasClean] = options.wasClean === undefined ? false : options.wasClean;
+  }
+
+  /**
+   * @type {Number}
+   */
+  get code() {
+    return this[kCode];
+  }
+
+  /**
+   * @type {String}
+   */
+  get reason() {
+    return this[kReason];
+  }
+
+  /**
+   * @type {Boolean}
+   */
+  get wasClean() {
+    return this[kWasClean];
+  }
+}
+
+Object.defineProperty(CloseEvent.prototype, 'code', { enumerable: true });
+Object.defineProperty(CloseEvent.prototype, 'reason', { enumerable: true });
+Object.defineProperty(CloseEvent.prototype, 'wasClean', { enumerable: true });
+
+/**
+ * Class representing an error event.
+ *
+ * @extends Event
+ */
+class ErrorEvent extends Event {
+  /**
+   * Create a new `ErrorEvent`.
+   *
+   * @param {String} type The name of the event
+   * @param {Object} [options] A dictionary object that allows for setting
+   *     attributes via object members of the same name
+   * @param {*} [options.error=null] The error that generated this event
+   * @param {String} [options.message=''] The error message
+   */
+  constructor(type, options = {}) {
+    super(type);
+
+    this[kError] = options.error === undefined ? null : options.error;
+    this[kMessage] = options.message === undefined ? '' : options.message;
+  }
+
+  /**
+   * @type {*}
+   */
+  get error() {
+    return this[kError];
+  }
+
+  /**
+   * @type {String}
+   */
+  get message() {
+    return this[kMessage];
+  }
+}
+
+Object.defineProperty(ErrorEvent.prototype, 'error', { enumerable: true });
+Object.defineProperty(ErrorEvent.prototype, 'message', { enumerable: true });
+
+/**
+ * Class representing a message event.
+ *
+ * @extends Event
+ */
+class MessageEvent extends Event {
+  /**
+   * Create a new `MessageEvent`.
+   *
+   * @param {String} type The name of the event
+   * @param {Object} [options] A dictionary object that allows for setting
+   *     attributes via object members of the same name
+   * @param {*} [options.data=null] The message content
+   */
+  constructor(type, options = {}) {
+    super(type);
+
+    this[kData] = options.data === undefined ? null : options.data;
+  }
+
+  /**
+   * @type {*}
+   */
+  get data() {
+    return this[kData];
+  }
+}
+
+Object.defineProperty(MessageEvent.prototype, 'data', { enumerable: true });
+
+/**
+ * This provides methods for emulating the `EventTarget` interface. It's not
+ * meant to be used directly.
+ *
+ * @mixin
+ */
+const EventTarget = {
+  /**
+   * Register an event listener.
+   *
+   * @param {String} type A string representing the event type to listen for
+   * @param {(Function|Object)} handler The listener to add
+   * @param {Object} [options] An options object specifies characteristics about
+   *     the event listener
+   * @param {Boolean} [options.once=false] A `Boolean` indicating that the
+   *     listener should be invoked at most once after being added. If `true`,
+   *     the listener would be automatically removed when invoked.
+   * @public
+   */
+  addEventListener(type, handler, options = {}) {
+    for (const listener of this.listeners(type)) {
+      if (
+        !options[kForOnEventAttribute] &&
+        listener[kListener] === handler &&
+        !listener[kForOnEventAttribute]
+      ) {
+        return;
+      }
+    }
+
+    let wrapper;
+
+    if (type === 'message') {
+      wrapper = function onMessage(data, isBinary) {
+        const event = new MessageEvent('message', {
+          data: isBinary ? data : data.toString()
+        });
+
+        event[kTarget] = this;
+        callListener(handler, this, event);
+      };
+    } else if (type === 'close') {
+      wrapper = function onClose(code, message) {
+        const event = new CloseEvent('close', {
+          code,
+          reason: message.toString(),
+          wasClean: this._closeFrameReceived && this._closeFrameSent
+        });
+
+        event[kTarget] = this;
+        callListener(handler, this, event);
+      };
+    } else if (type === 'error') {
+      wrapper = function onError(error) {
+        const event = new ErrorEvent('error', {
+          error,
+          message: error.message
+        });
+
+        event[kTarget] = this;
+        callListener(handler, this, event);
+      };
+    } else if (type === 'open') {
+      wrapper = function onOpen() {
+        const event = new Event('open');
+
+        event[kTarget] = this;
+        callListener(handler, this, event);
+      };
+    } else {
+      return;
+    }
+
+    wrapper[kForOnEventAttribute] = !!options[kForOnEventAttribute];
+    wrapper[kListener] = handler;
+
+    if (options.once) {
+      this.once(type, wrapper);
+    } else {
+      this.on(type, wrapper);
+    }
+  },
+
+  /**
+   * Remove an event listener.
+   *
+   * @param {String} type A string representing the event type to remove
+   * @param {(Function|Object)} handler The listener to remove
+   * @public
+   */
+  removeEventListener(type, handler) {
+    for (const listener of this.listeners(type)) {
+      if (listener[kListener] === handler && !listener[kForOnEventAttribute]) {
+        this.removeListener(type, listener);
+        break;
+      }
+    }
+  }
+};
+
+module.exports = {
+  CloseEvent,
+  ErrorEvent,
+  Event,
+  EventTarget,
+  MessageEvent
+};
+
+/**
+ * Call an event listener
+ *
+ * @param {(Function|Object)} listener The listener to call
+ * @param {*} thisArg The value to use as `this`` when calling the listener
+ * @param {Event} event The event to pass to the listener
+ * @private
+ */
+function callListener(listener, thisArg, event) {
+  if (typeof listener === 'object' && listener.handleEvent) {
+    listener.handleEvent.call(listener, event);
+  } else {
+    listener.call(thisArg, event);
+  }
+}

engine/ds-screencast/node_modules/ws/lib/extension.js

@@ -0,0 +1,203 @@
+'use strict';
+
+const { tokenChars } = require('./validation');
+
+/**
+ * Adds an offer to the map of extension offers or a parameter to the map of
+ * parameters.
+ *
+ * @param {Object} dest The map of extension offers or parameters
+ * @param {String} name The extension or parameter name
+ * @param {(Object|Boolean|String)} elem The extension parameters or the
+ *     parameter value
+ * @private
+ */
+function push(dest, name, elem) {
+  if (dest[name] === undefined) dest[name] = [elem];
+  else dest[name].push(elem);
+}
+
+/**
+ * Parses the `Sec-WebSocket-Extensions` header into an object.
+ *
+ * @param {String} header The field value of the header
+ * @return {Object} The parsed object
+ * @public
+ */
+function parse(header) {
+  const offers = Object.create(null);
+  let params = Object.create(null);
+  let mustUnescape = false;
+  let isEscaping = false;
+  let inQuotes = false;
+  let extensionName;
+  let paramName;
+  let start = -1;
+  let code = -1;
+  let end = -1;
+  let i = 0;
+
+  for (; i < header.length; i++) {
+    code = header.charCodeAt(i);
+
+    if (extensionName === undefined) {
+      if (end === -1 && tokenChars[code] === 1) {
+        if (start === -1) start = i;
+      } else if (
+        i !== 0 &&
+        (code === 0x20 /* ' ' */ || code === 0x09) /* '\t' */
+      ) {
+        if (end === -1 && start !== -1) end = i;
+      } else if (code === 0x3b /* ';' */ || code === 0x2c /* ',' */) {
+        if (start === -1) {
+          throw new SyntaxError(`Unexpected character at index ${i}`);
+        }
+
+        if (end === -1) end = i;
+        const name = header.slice(start, end);
+        if (code === 0x2c) {
+          push(offers, name, params);
+          params = Object.create(null);
+        } else {
+          extensionName = name;
+        }
+
+        start = end = -1;
+      } else {
+        throw new SyntaxError(`Unexpected character at index ${i}`);
+      }
+    } else if (paramName === undefined) {
+      if (end === -1 && tokenChars[code] === 1) {
+        if (start === -1) start = i;
+      } else if (code === 0x20 || code === 0x09) {
+        if (end === -1 && start !== -1) end = i;
+      } else if (code === 0x3b || code === 0x2c) {
+        if (start === -1) {
+          throw new SyntaxError(`Unexpected character at index ${i}`);
+        }
+
+        if (end === -1) end = i;
+        push(params, header.slice(start, end), true);
+        if (code === 0x2c) {
+          push(offers, extensionName, params);
+          params = Object.create(null);
+          extensionName = undefined;
+        }
+
+        start = end = -1;
+      } else if (code === 0x3d /* '=' */ && start !== -1 && end === -1) {
+        paramName = header.slice(start, i);
+        start = end = -1;
+      } else {
+        throw new SyntaxError(`Unexpected character at index ${i}`);
+      }
+    } else {
+      //
+      // The value of a quoted-string after unescaping must conform to the
+      // token ABNF, so only token characters are valid.
+      // Ref: https://tools.ietf.org/html/rfc6455#section-9.1
+      //
+      if (isEscaping) {
+        if (tokenChars[code] !== 1) {
+          throw new SyntaxError(`Unexpected character at index ${i}`);
+        }
+        if (start === -1) start = i;
+        else if (!mustUnescape) mustUnescape = true;
+        isEscaping = false;
+      } else if (inQuotes) {
+        if (tokenChars[code] === 1) {
+          if (start === -1) start = i;
+        } else if (code === 0x22 /* '"' */ && start !== -1) {
+          inQuotes = false;
+          end = i;
+        } else if (code === 0x5c /* '\' */) {
+          isEscaping = true;
+        } else {
+          throw new SyntaxError(`Unexpected character at index ${i}`);
+        }
+      } else if (code === 0x22 && header.charCodeAt(i - 1) === 0x3d) {
+        inQuotes = true;
+      } else if (end === -1 && tokenChars[code] === 1) {
+        if (start === -1) start = i;
+      } else if (start !== -1 && (code === 0x20 || code === 0x09)) {
+        if (end === -1) end = i;
+      } else if (code === 0x3b || code === 0x2c) {
+        if (start === -1) {
+          throw new SyntaxError(`Unexpected character at index ${i}`);
+        }
+
+        if (end === -1) end = i;
+        let value = header.slice(start, end);
+        if (mustUnescape) {
+          value = value.replace(/\\/g, '');
+          mustUnescape = false;
+        }
+        push(params, paramName, value);
+        if (code === 0x2c) {
+          push(offers, extensionName, params);
+          params = Object.create(null);
+          extensionName = undefined;
+        }
+
+        paramName = undefined;
+        start = end = -1;
+      } else {
+        throw new SyntaxError(`Unexpected character at index ${i}`);
+      }
+    }
+  }
+
+  if (start === -1 || inQuotes || code === 0x20 || code === 0x09) {
+    throw new SyntaxError('Unexpected end of input');
+  }
+
+  if (end === -1) end = i;
+  const token = header.slice(start, end);
+  if (extensionName === undefined) {
+    push(offers, token, params);
+  } else {
+    if (paramName === undefined) {
+      push(params, token, true);
+    } else if (mustUnescape) {
+      push(params, paramName, token.replace(/\\/g, ''));
+    } else {
+      push(params, paramName, token);
+    }
+    push(offers, extensionName, params);
+  }
+
+  return offers;
+}
+
+/**
+ * Builds the `Sec-WebSocket-Extensions` header field value.
+ *
+ * @param {Object} extensions The map of extensions and parameters to format
+ * @return {String} A string representing the given object
+ * @public
+ */
+function format(extensions) {
+  return Object.keys(extensions)
+    .map((extension) => {
+      let configurations = extensions[extension];
+      if (!Array.isArray(configurations)) configurations = [configurations];
+      return configurations
+        .map((params) => {
+          return [extension]
+            .concat(
+              Object.keys(params).map((k) => {
+                let values = params[k];
+                if (!Array.isArray(values)) values = [values];
+                return values
+                  .map((v) => (v === true ? k : `${k}=${v}`))
+                  .join('; ');
+              })
+            )
+            .join('; ');
+        })
+        .join(', ');
+    })
+    .join(', ');
+}
+
+module.exports = { format, parse };

engine/ds-screencast/node_modules/ws/lib/limiter.js

@@ -0,0 +1,55 @@
+'use strict';
+
+const kDone = Symbol('kDone');
+const kRun = Symbol('kRun');
+
+/**
+ * A very simple job queue with adjustable concurrency. Adapted from
+ * https://github.com/STRML/async-limiter
+ */
+class Limiter {
+  /**
+   * Creates a new `Limiter`.
+   *
+   * @param {Number} [concurrency=Infinity] The maximum number of jobs allowed
+   *     to run concurrently
+   */
+  constructor(concurrency) {
+    this[kDone] = () => {
+      this.pending--;
+      this[kRun]();
+    };
+    this.concurrency = concurrency || Infinity;
+    this.jobs = [];
+    this.pending = 0;
+  }
+
+  /**
+   * Adds a job to the queue.
+   *
+   * @param {Function} job The job to run
+   * @public
+   */
+  add(job) {
+    this.jobs.push(job);
+    this[kRun]();
+  }
+
+  /**
+   * Removes a job from the queue and runs it if possible.
+   *
+   * @private
+   */
+  [kRun]() {
+    if (this.pending === this.concurrency) return;
+
+    if (this.jobs.length) {
+      const job = this.jobs.shift();
+
+      this.pending++;
+      job(this[kDone]);
+    }
+  }
+}
+
+module.exports = Limiter;

engine/ds-screencast/node_modules/ws/lib/permessage-deflate.js

@@ -0,0 +1,528 @@
+'use strict';
+
+const zlib = require('zlib');
+
+const bufferUtil = require('./buffer-util');
+const Limiter = require('./limiter');
+const { kStatusCode } = require('./constants');
+
+const FastBuffer = Buffer[Symbol.species];
+const TRAILER = Buffer.from([0x00, 0x00, 0xff, 0xff]);
+const kPerMessageDeflate = Symbol('permessage-deflate');
+const kTotalLength = Symbol('total-length');
+const kCallback = Symbol('callback');
+const kBuffers = Symbol('buffers');
+const kError = Symbol('error');
+
+//
+// We limit zlib concurrency, which prevents severe memory fragmentation
+// as documented in https://github.com/nodejs/node/issues/8871#issuecomment-250915913
+// and https://github.com/websockets/ws/issues/1202
+//
+// Intentionally global; it's the global thread pool that's an issue.
+//
+let zlibLimiter;
+
+/**
+ * permessage-deflate implementation.
+ */
+class PerMessageDeflate {
+  /**
+   * Creates a PerMessageDeflate instance.
+   *
+   * @param {Object} [options] Configuration options
+   * @param {(Boolean|Number)} [options.clientMaxWindowBits] Advertise support
+   *     for, or request, a custom client window size
+   * @param {Boolean} [options.clientNoContextTakeover=false] Advertise/
+   *     acknowledge disabling of client context takeover
+   * @param {Number} [options.concurrencyLimit=10] The number of concurrent
+   *     calls to zlib
+   * @param {(Boolean|Number)} [options.serverMaxWindowBits] Request/confirm the
+   *     use of a custom server window size
+   * @param {Boolean} [options.serverNoContextTakeover=false] Request/accept
+   *     disabling of server context takeover
+   * @param {Number} [options.threshold=1024] Size (in bytes) below which
+   *     messages should not be compressed if context takeover is disabled
+   * @param {Object} [options.zlibDeflateOptions] Options to pass to zlib on
+   *     deflate
+   * @param {Object} [options.zlibInflateOptions] Options to pass to zlib on
+   *     inflate
+   * @param {Boolean} [isServer=false] Create the instance in either server or
+   *     client mode
+   * @param {Number} [maxPayload=0] The maximum allowed message length
+   */
+  constructor(options, isServer, maxPayload) {
+    this._maxPayload = maxPayload | 0;
+    this._options = options || {};
+    this._threshold =
+      this._options.threshold !== undefined ? this._options.threshold : 1024;
+    this._isServer = !!isServer;
+    this._deflate = null;
+    this._inflate = null;
+
+    this.params = null;
+
+    if (!zlibLimiter) {
+      const concurrency =
+        this._options.concurrencyLimit !== undefined
+          ? this._options.concurrencyLimit
+          : 10;
+      zlibLimiter = new Limiter(concurrency);
+    }
+  }
+
+  /**
+   * @type {String}
+   */
+  static get extensionName() {
+    return 'permessage-deflate';
+  }
+
+  /**
+   * Create an extension negotiation offer.
+   *
+   * @return {Object} Extension parameters
+   * @public
+   */
+  offer() {
+    const params = {};
+
+    if (this._options.serverNoContextTakeover) {
+      params.server_no_context_takeover = true;
+    }
+    if (this._options.clientNoContextTakeover) {
+      params.client_no_context_takeover = true;
+    }
+    if (this._options.serverMaxWindowBits) {
+      params.server_max_window_bits = this._options.serverMaxWindowBits;
+    }
+    if (this._options.clientMaxWindowBits) {
+      params.client_max_window_bits = this._options.clientMaxWindowBits;
+    } else if (this._options.clientMaxWindowBits == null) {
+      params.client_max_window_bits = true;
+    }
+
+    return params;
+  }
+
+  /**
+   * Accept an extension negotiation offer/response.
+   *
+   * @param {Array} configurations The extension negotiation offers/reponse
+   * @return {Object} Accepted configuration
+   * @public
+   */
+  accept(configurations) {
+    configurations = this.normalizeParams(configurations);
+
+    this.params = this._isServer
+      ? this.acceptAsServer(configurations)
+      : this.acceptAsClient(configurations);
+
+    return this.params;
+  }
+
+  /**
+   * Releases all resources used by the extension.
+   *
+   * @public
+   */
+  cleanup() {
+    if (this._inflate) {
+      this._inflate.close();
+      this._inflate = null;
+    }
+
+    if (this._deflate) {
+      const callback = this._deflate[kCallback];
+
+      this._deflate.close();
+      this._deflate = null;
+
+      if (callback) {
+        callback(
+          new Error(
+            'The deflate stream was closed while data was being processed'
+          )
+        );
+      }
+    }
+  }
+
+  /**
+   *  Accept an extension negotiation offer.
+   *
+   * @param {Array} offers The extension negotiation offers
+   * @return {Object} Accepted configuration
+   * @private
+   */
+  acceptAsServer(offers) {
+    const opts = this._options;
+    const accepted = offers.find((params) => {
+      if (
+        (opts.serverNoContextTakeover === false &&
+          params.server_no_context_takeover) ||
+        (params.server_max_window_bits &&
+          (opts.serverMaxWindowBits === false ||
+            (typeof opts.serverMaxWindowBits === 'number' &&
+              opts.serverMaxWindowBits > params.server_max_window_bits))) ||
+        (typeof opts.clientMaxWindowBits === 'number' &&
+          !params.client_max_window_bits)
+      ) {
+        return false;
+      }
+
+      return true;
+    });
+
+    if (!accepted) {
+      throw new Error('None of the extension offers can be accepted');
+    }
+
+    if (opts.serverNoContextTakeover) {
+      accepted.server_no_context_takeover = true;
+    }
+    if (opts.clientNoContextTakeover) {
+      accepted.client_no_context_takeover = true;
+    }
+    if (typeof opts.serverMaxWindowBits === 'number') {
+      accepted.server_max_window_bits = opts.serverMaxWindowBits;
+    }
+    if (typeof opts.clientMaxWindowBits === 'number') {
+      accepted.client_max_window_bits = opts.clientMaxWindowBits;
+    } else if (
+      accepted.client_max_window_bits === true ||
+      opts.clientMaxWindowBits === false
+    ) {
+      delete accepted.client_max_window_bits;
+    }
+
+    return accepted;
+  }
+
+  /**
+   * Accept the extension negotiation response.
+   *
+   * @param {Array} response The extension negotiation response
+   * @return {Object} Accepted configuration
+   * @private
+   */
+  acceptAsClient(response) {
+    const params = response[0];
+
+    if (
+      this._options.clientNoContextTakeover === false &&
+      params.client_no_context_takeover
+    ) {
+      throw new Error('Unexpected parameter "client_no_context_takeover"');
+    }
+
+    if (!params.client_max_window_bits) {
+      if (typeof this._options.clientMaxWindowBits === 'number') {
+        params.client_max_window_bits = this._options.clientMaxWindowBits;
+      }
+    } else if (
+      this._options.clientMaxWindowBits === false ||
+      (typeof this._options.clientMaxWindowBits === 'number' &&
+        params.client_max_window_bits > this._options.clientMaxWindowBits)
+    ) {
+      throw new Error(
+        'Unexpected or invalid parameter "client_max_window_bits"'
+      );
+    }
+
+    return params;
+  }
+
+  /**
+   * Normalize parameters.
+   *
+   * @param {Array} configurations The extension negotiation offers/reponse
+   * @return {Array} The offers/response with normalized parameters
+   * @private
+   */
+  normalizeParams(configurations) {
+    configurations.forEach((params) => {
+      Object.keys(params).forEach((key) => {
+        let value = params[key];
+
+        if (value.length > 1) {
+          throw new Error(`Parameter "${key}" must have only a single value`);
+        }
+
+        value = value[0];
+
+        if (key === 'client_max_window_bits') {
+          if (value !== true) {
+            const num = +value;
+            if (!Number.isInteger(num) || num < 8 || num > 15) {
+              throw new TypeError(
+                `Invalid value for parameter "${key}": ${value}`
+              );
+            }
+            value = num;
+          } else if (!this._isServer) {
+            throw new TypeError(
+              `Invalid value for parameter "${key}": ${value}`
+            );
+          }
+        } else if (key === 'server_max_window_bits') {
+          const num = +value;
+          if (!Number.isInteger(num) || num < 8 || num > 15) {
+            throw new TypeError(
+              `Invalid value for parameter "${key}": ${value}`
+            );
+          }
+          value = num;
+        } else if (
+          key === 'client_no_context_takeover' ||
+          key === 'server_no_context_takeover'
+        ) {
+          if (value !== true) {
+            throw new TypeError(
+              `Invalid value for parameter "${key}": ${value}`
+            );
+          }
+        } else {
+          throw new Error(`Unknown parameter "${key}"`);
+        }
+
+        params[key] = value;
+      });
+    });
+
+    return configurations;
+  }
+
+  /**
+   * Decompress data. Concurrency limited.
+   *
+   * @param {Buffer} data Compressed data
+   * @param {Boolean} fin Specifies whether or not this is the last fragment
+   * @param {Function} callback Callback
+   * @public
+   */
+  decompress(data, fin, callback) {
+    zlibLimiter.add((done) => {
+      this._decompress(data, fin, (err, result) => {
+        done();
+        callback(err, result);
+      });
+    });
+  }
+
+  /**
+   * Compress data. Concurrency limited.
+   *
+   * @param {(Buffer|String)} data Data to compress
+   * @param {Boolean} fin Specifies whether or not this is the last fragment
+   * @param {Function} callback Callback
+   * @public
+   */
+  compress(data, fin, callback) {
+    zlibLimiter.add((done) => {
+      this._compress(data, fin, (err, result) => {
+        done();
+        callback(err, result);
+      });
+    });
+  }
+
+  /**
+   * Decompress data.
+   *
+   * @param {Buffer} data Compressed data
+   * @param {Boolean} fin Specifies whether or not this is the last fragment
+   * @param {Function} callback Callback
+   * @private
+   */
+  _decompress(data, fin, callback) {
+    const endpoint = this._isServer ? 'client' : 'server';
+
+    if (!this._inflate) {
+      const key = `${endpoint}_max_window_bits`;
+      const windowBits =
+        typeof this.params[key] !== 'number'
+          ? zlib.Z_DEFAULT_WINDOWBITS
+          : this.params[key];
+
+      this._inflate = zlib.createInflateRaw({
+        ...this._options.zlibInflateOptions,
+        windowBits
+      });
+      this._inflate[kPerMessageDeflate] = this;
+      this._inflate[kTotalLength] = 0;
+      this._inflate[kBuffers] = [];
+      this._inflate.on('error', inflateOnError);
+      this._inflate.on('data', inflateOnData);
+    }
+
+    this._inflate[kCallback] = callback;
+
+    this._inflate.write(data);
+    if (fin) this._inflate.write(TRAILER);
+
+    this._inflate.flush(() => {
+      const err = this._inflate[kError];
+
+      if (err) {
+        this._inflate.close();
+        this._inflate = null;
+        callback(err);
+        return;
+      }
+
+      const data = bufferUtil.concat(
+        this._inflate[kBuffers],
+        this._inflate[kTotalLength]
+      );
+
+      if (this._inflate._readableState.endEmitted) {
+        this._inflate.close();
+        this._inflate = null;
+      } else {
+        this._inflate[kTotalLength] = 0;
+        this._inflate[kBuffers] = [];
+
+        if (fin && this.params[`${endpoint}_no_context_takeover`]) {
+          this._inflate.reset();
+        }
+      }
+
+      callback(null, data);
+    });
+  }
+
+  /**
+   * Compress data.
+   *
+   * @param {(Buffer|String)} data Data to compress
+   * @param {Boolean} fin Specifies whether or not this is the last fragment
+   * @param {Function} callback Callback
+   * @private
+   */
+  _compress(data, fin, callback) {
+    const endpoint = this._isServer ? 'server' : 'client';
+
+    if (!this._deflate) {
+      const key = `${endpoint}_max_window_bits`;
+      const windowBits =
+        typeof this.params[key] !== 'number'
+          ? zlib.Z_DEFAULT_WINDOWBITS
+          : this.params[key];
+
+      this._deflate = zlib.createDeflateRaw({
+        ...this._options.zlibDeflateOptions,
+        windowBits
+      });
+
+      this._deflate[kTotalLength] = 0;
+      this._deflate[kBuffers] = [];
+
+      this._deflate.on('data', deflateOnData);
+    }
+
+    this._deflate[kCallback] = callback;
+
+    this._deflate.write(data);
+    this._deflate.flush(zlib.Z_SYNC_FLUSH, () => {
+      if (!this._deflate) {
+        //
+        // The deflate stream was closed while data was being processed.
+        //
+        return;
+      }
+
+      let data = bufferUtil.concat(
+        this._deflate[kBuffers],
+        this._deflate[kTotalLength]
+      );
+
+      if (fin) {
+        data = new FastBuffer(data.buffer, data.byteOffset, data.length - 4);
+      }
+
+      //
+      // Ensure that the callback will not be called again in
+      // `PerMessageDeflate#cleanup()`.
+      //
+      this._deflate[kCallback] = null;
+
+      this._deflate[kTotalLength] = 0;
+      this._deflate[kBuffers] = [];
+
+      if (fin && this.params[`${endpoint}_no_context_takeover`]) {
+        this._deflate.reset();
+      }
+
+      callback(null, data);
+    });
+  }
+}
+
+module.exports = PerMessageDeflate;
+
+/**
+ * The listener of the `zlib.DeflateRaw` stream `'data'` event.
+ *
+ * @param {Buffer} chunk A chunk of data
+ * @private
+ */
+function deflateOnData(chunk) {
+  this[kBuffers].push(chunk);
+  this[kTotalLength] += chunk.length;
+}
+
+/**
+ * The listener of the `zlib.InflateRaw` stream `'data'` event.
+ *
+ * @param {Buffer} chunk A chunk of data
+ * @private
+ */
+function inflateOnData(chunk) {
+  this[kTotalLength] += chunk.length;
+
+  if (
+    this[kPerMessageDeflate]._maxPayload < 1 ||
+    this[kTotalLength] <= this[kPerMessageDeflate]._maxPayload
+  ) {
+    this[kBuffers].push(chunk);
+    return;
+  }
+
+  this[kError] = new RangeError('Max payload size exceeded');
+  this[kError].code = 'WS_ERR_UNSUPPORTED_MESSAGE_LENGTH';
+  this[kError][kStatusCode] = 1009;
+  this.removeListener('data', inflateOnData);
+
+  //
+  // The choice to employ `zlib.reset()` over `zlib.close()` is dictated by the
+  // fact that in Node.js versions prior to 13.10.0, the callback for
+  // `zlib.flush()` is not called if `zlib.close()` is used. Utilizing
+  // `zlib.reset()` ensures that either the callback is invoked or an error is
+  // emitted.
+  //
+  this.reset();
+}
+
+/**
+ * The listener of the `zlib.InflateRaw` stream `'error'` event.
+ *
+ * @param {Error} err The emitted error
+ * @private
+ */
+function inflateOnError(err) {
+  //
+  // There is no need to call `Zlib#close()` as the handle is automatically
+  // closed when an error is emitted.
+  //
+  this[kPerMessageDeflate]._inflate = null;
+
+  if (this[kError]) {
+    this[kCallback](this[kError]);
+    return;
+  }
+
+  err[kStatusCode] = 1007;
+  this[kCallback](err);
+}

engine/ds-screencast/node_modules/ws/lib/receiver.js

@@ -0,0 +1,706 @@
+'use strict';
+
+const { Writable } = require('stream');
+
+const PerMessageDeflate = require('./permessage-deflate');
+const {
+  BINARY_TYPES,
+  EMPTY_BUFFER,
+  kStatusCode,
+  kWebSocket
+} = require('./constants');
+const { concat, toArrayBuffer, unmask } = require('./buffer-util');
+const { isValidStatusCode, isValidUTF8 } = require('./validation');
+
+const FastBuffer = Buffer[Symbol.species];
+
+const GET_INFO = 0;
+const GET_PAYLOAD_LENGTH_16 = 1;
+const GET_PAYLOAD_LENGTH_64 = 2;
+const GET_MASK = 3;
+const GET_DATA = 4;
+const INFLATING = 5;
+const DEFER_EVENT = 6;
+
+/**
+ * HyBi Receiver implementation.
+ *
+ * @extends Writable
+ */
+class Receiver extends Writable {
+  /**
+   * Creates a Receiver instance.
+   *
+   * @param {Object} [options] Options object
+   * @param {Boolean} [options.allowSynchronousEvents=true] Specifies whether
+   *     any of the `'message'`, `'ping'`, and `'pong'` events can be emitted
+   *     multiple times in the same tick
+   * @param {String} [options.binaryType=nodebuffer] The type for binary data
+   * @param {Object} [options.extensions] An object containing the negotiated
+   *     extensions
+   * @param {Boolean} [options.isServer=false] Specifies whether to operate in
+   *     client or server mode
+   * @param {Number} [options.maxPayload=0] The maximum allowed message length
+   * @param {Boolean} [options.skipUTF8Validation=false] Specifies whether or
+   *     not to skip UTF-8 validation for text and close messages
+   */
+  constructor(options = {}) {
+    super();
+
+    this._allowSynchronousEvents =
+      options.allowSynchronousEvents !== undefined
+        ? options.allowSynchronousEvents
+        : true;
+    this._binaryType = options.binaryType || BINARY_TYPES[0];
+    this._extensions = options.extensions || {};
+    this._isServer = !!options.isServer;
+    this._maxPayload = options.maxPayload | 0;
+    this._skipUTF8Validation = !!options.skipUTF8Validation;
+    this[kWebSocket] = undefined;
+
+    this._bufferedBytes = 0;
+    this._buffers = [];
+
+    this._compressed = false;
+    this._payloadLength = 0;
+    this._mask = undefined;
+    this._fragmented = 0;
+    this._masked = false;
+    this._fin = false;
+    this._opcode = 0;
+
+    this._totalPayloadLength = 0;
+    this._messageLength = 0;
+    this._fragments = [];
+
+    this._errored = false;
+    this._loop = false;
+    this._state = GET_INFO;
+  }
+
+  /**
+   * Implements `Writable.prototype._write()`.
+   *
+   * @param {Buffer} chunk The chunk of data to write
+   * @param {String} encoding The character encoding of `chunk`
+   * @param {Function} cb Callback
+   * @private
+   */
+  _write(chunk, encoding, cb) {
+    if (this._opcode === 0x08 && this._state == GET_INFO) return cb();
+
+    this._bufferedBytes += chunk.length;
+    this._buffers.push(chunk);
+    this.startLoop(cb);
+  }
+
+  /**
+   * Consumes `n` bytes from the buffered data.
+   *
+   * @param {Number} n The number of bytes to consume
+   * @return {Buffer} The consumed bytes
+   * @private
+   */
+  consume(n) {
+    this._bufferedBytes -= n;
+
+    if (n === this._buffers[0].length) return this._buffers.shift();
+
+    if (n < this._buffers[0].length) {
+      const buf = this._buffers[0];
+      this._buffers[0] = new FastBuffer(
+        buf.buffer,
+        buf.byteOffset + n,
+        buf.length - n
+      );
+
+      return new FastBuffer(buf.buffer, buf.byteOffset, n);
+    }
+
+    const dst = Buffer.allocUnsafe(n);
+
+    do {
+      const buf = this._buffers[0];
+      const offset = dst.length - n;
+
+      if (n >= buf.length) {
+        dst.set(this._buffers.shift(), offset);
+      } else {
+        dst.set(new Uint8Array(buf.buffer, buf.byteOffset, n), offset);
+        this._buffers[0] = new FastBuffer(
+          buf.buffer,
+          buf.byteOffset + n,
+          buf.length - n
+        );
+      }
+
+      n -= buf.length;
+    } while (n > 0);
+
+    return dst;
+  }
+
+  /**
+   * Starts the parsing loop.
+   *
+   * @param {Function} cb Callback
+   * @private
+   */
+  startLoop(cb) {
+    this._loop = true;
+
+    do {
+      switch (this._state) {
+        case GET_INFO:
+          this.getInfo(cb);
+          break;
+        case GET_PAYLOAD_LENGTH_16:
+          this.getPayloadLength16(cb);
+          break;
+        case GET_PAYLOAD_LENGTH_64:
+          this.getPayloadLength64(cb);
+          break;
+        case GET_MASK:
+          this.getMask();
+          break;
+        case GET_DATA:
+          this.getData(cb);
+          break;
+        case INFLATING:
+        case DEFER_EVENT:
+          this._loop = false;
+          return;
+      }
+    } while (this._loop);
+
+    if (!this._errored) cb();
+  }
+
+  /**
+   * Reads the first two bytes of a frame.
+   *
+   * @param {Function} cb Callback
+   * @private
+   */
+  getInfo(cb) {
+    if (this._bufferedBytes < 2) {
+      this._loop = false;
+      return;
+    }
+
+    const buf = this.consume(2);
+
+    if ((buf[0] & 0x30) !== 0x00) {
+      const error = this.createError(
+        RangeError,
+        'RSV2 and RSV3 must be clear',
+        true,
+        1002,
+        'WS_ERR_UNEXPECTED_RSV_2_3'
+      );
+
+      cb(error);
+      return;
+    }
+
+    const compressed = (buf[0] & 0x40) === 0x40;
+
+    if (compressed && !this._extensions[PerMessageDeflate.extensionName]) {
+      const error = this.createError(
+        RangeError,
+        'RSV1 must be clear',
+        true,
+        1002,
+        'WS_ERR_UNEXPECTED_RSV_1'
+      );
+
+      cb(error);
+      return;
+    }
+
+    this._fin = (buf[0] & 0x80) === 0x80;
+    this._opcode = buf[0] & 0x0f;
+    this._payloadLength = buf[1] & 0x7f;
+
+    if (this._opcode === 0x00) {
+      if (compressed) {
+        const error = this.createError(
+          RangeError,
+          'RSV1 must be clear',
+          true,
+          1002,
+          'WS_ERR_UNEXPECTED_RSV_1'
+        );
+
+        cb(error);
+        return;
+      }
+
+      if (!this._fragmented) {
+        const error = this.createError(
+          RangeError,
+          'invalid opcode 0',
+          true,
+          1002,
+          'WS_ERR_INVALID_OPCODE'
+        );
+
+        cb(error);
+        return;
+      }
+
+      this._opcode = this._fragmented;
+    } else if (this._opcode === 0x01 || this._opcode === 0x02) {
+      if (this._fragmented) {
+        const error = this.createError(
+          RangeError,
+          `invalid opcode ${this._opcode}`,
+          true,
+          1002,
+          'WS_ERR_INVALID_OPCODE'
+        );
+
+        cb(error);
+        return;
+      }
+
+      this._compressed = compressed;
+    } else if (this._opcode > 0x07 && this._opcode < 0x0b) {
+      if (!this._fin) {
+        const error = this.createError(
+          RangeError,
+          'FIN must be set',
+          true,
+          1002,
+          'WS_ERR_EXPECTED_FIN'
+        );
+
+        cb(error);
+        return;
+      }
+
+      if (compressed) {
+        const error = this.createError(
+          RangeError,
+          'RSV1 must be clear',
+          true,
+          1002,
+          'WS_ERR_UNEXPECTED_RSV_1'
+        );
+
+        cb(error);
+        return;
+      }
+
+      if (
+        this._payloadLength > 0x7d ||
+        (this._opcode === 0x08 && this._payloadLength === 1)
+      ) {
+        const error = this.createError(
+          RangeError,
+          `invalid payload length ${this._payloadLength}`,
+          true,
+          1002,
+          'WS_ERR_INVALID_CONTROL_PAYLOAD_LENGTH'
+        );
+
+        cb(error);
+        return;
+      }
+    } else {
+      const error = this.createError(
+        RangeError,
+        `invalid opcode ${this._opcode}`,
+        true,
+        1002,
+        'WS_ERR_INVALID_OPCODE'
+      );
+
+      cb(error);
+      return;
+    }
+
+    if (!this._fin && !this._fragmented) this._fragmented = this._opcode;
+    this._masked = (buf[1] & 0x80) === 0x80;
+
+    if (this._isServer) {
+      if (!this._masked) {
+        const error = this.createError(
+          RangeError,
+          'MASK must be set',
+          true,
+          1002,
+          'WS_ERR_EXPECTED_MASK'
+        );
+
+        cb(error);
+        return;
+      }
+    } else if (this._masked) {
+      const error = this.createError(
+        RangeError,
+        'MASK must be clear',
+        true,
+        1002,
+        'WS_ERR_UNEXPECTED_MASK'
+      );
+
+      cb(error);
+      return;
+    }
+
+    if (this._payloadLength === 126) this._state = GET_PAYLOAD_LENGTH_16;
+    else if (this._payloadLength === 127) this._state = GET_PAYLOAD_LENGTH_64;
+    else this.haveLength(cb);
+  }
+
+  /**
+   * Gets extended payload length (7+16).
+   *
+   * @param {Function} cb Callback
+   * @private
+   */
+  getPayloadLength16(cb) {
+    if (this._bufferedBytes < 2) {
+      this._loop = false;
+      return;
+    }
+
+    this._payloadLength = this.consume(2).readUInt16BE(0);
+    this.haveLength(cb);
+  }
+
+  /**
+   * Gets extended payload length (7+64).
+   *
+   * @param {Function} cb Callback
+   * @private
+   */
+  getPayloadLength64(cb) {
+    if (this._bufferedBytes < 8) {
+      this._loop = false;
+      return;
+    }
+
+    const buf = this.consume(8);
+    const num = buf.readUInt32BE(0);
+
+    //
+    // The maximum safe integer in JavaScript is 2^53 - 1. An error is returned
+    // if payload length is greater than this number.
+    //
+    if (num > Math.pow(2, 53 - 32) - 1) {
+      const error = this.createError(
+        RangeError,
+        'Unsupported WebSocket frame: payload length > 2^53 - 1',
+        false,
+        1009,
+        'WS_ERR_UNSUPPORTED_DATA_PAYLOAD_LENGTH'
+      );
+
+      cb(error);
+      return;
+    }
+
+    this._payloadLength = num * Math.pow(2, 32) + buf.readUInt32BE(4);
+    this.haveLength(cb);
+  }
+
+  /**
+   * Payload length has been read.
+   *
+   * @param {Function} cb Callback
+   * @private
+   */
+  haveLength(cb) {
+    if (this._payloadLength && this._opcode < 0x08) {
+      this._totalPayloadLength += this._payloadLength;
+      if (this._totalPayloadLength > this._maxPayload && this._maxPayload > 0) {
+        const error = this.createError(
+          RangeError,
+          'Max payload size exceeded',
+          false,
+          1009,
+          'WS_ERR_UNSUPPORTED_MESSAGE_LENGTH'
+        );
+
+        cb(error);
+        return;
+      }
+    }
+
+    if (this._masked) this._state = GET_MASK;
+    else this._state = GET_DATA;
+  }
+
+  /**
+   * Reads mask bytes.
+   *
+   * @private
+   */
+  getMask() {
+    if (this._bufferedBytes < 4) {
+      this._loop = false;
+      return;
+    }
+
+    this._mask = this.consume(4);
+    this._state = GET_DATA;
+  }
+
+  /**
+   * Reads data bytes.
+   *
+   * @param {Function} cb Callback
+   * @private
+   */
+  getData(cb) {
+    let data = EMPTY_BUFFER;
+
+    if (this._payloadLength) {
+      if (this._bufferedBytes < this._payloadLength) {
+        this._loop = false;
+        return;
+      }
+
+      data = this.consume(this._payloadLength);
+
+      if (
+        this._masked &&
+        (this._mask[0] | this._mask[1] | this._mask[2] | this._mask[3]) !== 0
+      ) {
+        unmask(data, this._mask);
+      }
+    }
+
+    if (this._opcode > 0x07) {
+      this.controlMessage(data, cb);
+      return;
+    }
+
+    if (this._compressed) {
+      this._state = INFLATING;
+      this.decompress(data, cb);
+      return;
+    }
+
+    if (data.length) {
+      //
+      // This message is not compressed so its length is the sum of the payload
+      // length of all fragments.
+      //
+      this._messageLength = this._totalPayloadLength;
+      this._fragments.push(data);
+    }
+
+    this.dataMessage(cb);
+  }
+
+  /**
+   * Decompresses data.
+   *
+   * @param {Buffer} data Compressed data
+   * @param {Function} cb Callback
+   * @private
+   */
+  decompress(data, cb) {
+    const perMessageDeflate = this._extensions[PerMessageDeflate.extensionName];
+
+    perMessageDeflate.decompress(data, this._fin, (err, buf) => {
+      if (err) return cb(err);
+
+      if (buf.length) {
+        this._messageLength += buf.length;
+        if (this._messageLength > this._maxPayload && this._maxPayload > 0) {
+          const error = this.createError(
+            RangeError,
+            'Max payload size exceeded',
+            false,
+            1009,
+            'WS_ERR_UNSUPPORTED_MESSAGE_LENGTH'
+          );
+
+          cb(error);
+          return;
+        }
+
+        this._fragments.push(buf);
+      }
+
+      this.dataMessage(cb);
+      if (this._state === GET_INFO) this.startLoop(cb);
+    });
+  }
+
+  /**
+   * Handles a data message.
+   *
+   * @param {Function} cb Callback
+   * @private
+   */
+  dataMessage(cb) {
+    if (!this._fin) {
+      this._state = GET_INFO;
+      return;
+    }
+
+    const messageLength = this._messageLength;
+    const fragments = this._fragments;
+
+    this._totalPayloadLength = 0;
+    this._messageLength = 0;
+    this._fragmented = 0;
+    this._fragments = [];
+
+    if (this._opcode === 2) {
+      let data;
+
+      if (this._binaryType === 'nodebuffer') {
+        data = concat(fragments, messageLength);
+      } else if (this._binaryType === 'arraybuffer') {
+        data = toArrayBuffer(concat(fragments, messageLength));
+      } else if (this._binaryType === 'blob') {
+        data = new Blob(fragments);
+      } else {
+        data = fragments;
+      }
+
+      if (this._allowSynchronousEvents) {
+        this.emit('message', data, true);
+        this._state = GET_INFO;
+      } else {
+        this._state = DEFER_EVENT;
+        setImmediate(() => {
+          this.emit('message', data, true);
+          this._state = GET_INFO;
+          this.startLoop(cb);
+        });
+      }
+    } else {
+      const buf = concat(fragments, messageLength);
+
+      if (!this._skipUTF8Validation && !isValidUTF8(buf)) {
+        const error = this.createError(
+          Error,
+          'invalid UTF-8 sequence',
+          true,
+          1007,
+          'WS_ERR_INVALID_UTF8'
+        );
+
+        cb(error);
+        return;
+      }
+
+      if (this._state === INFLATING || this._allowSynchronousEvents) {
+        this.emit('message', buf, false);
+        this._state = GET_INFO;
+      } else {
+        this._state = DEFER_EVENT;
+        setImmediate(() => {
+          this.emit('message', buf, false);
+          this._state = GET_INFO;
+          this.startLoop(cb);
+        });
+      }
+    }
+  }
+
+  /**
+   * Handles a control message.
+   *
+   * @param {Buffer} data Data to handle
+   * @return {(Error|RangeError|undefined)} A possible error
+   * @private
+   */
+  controlMessage(data, cb) {
+    if (this._opcode === 0x08) {
+      if (data.length === 0) {
+        this._loop = false;
+        this.emit('conclude', 1005, EMPTY_BUFFER);
+        this.end();
+      } else {
+        const code = data.readUInt16BE(0);
+
+        if (!isValidStatusCode(code)) {
+          const error = this.createError(
+            RangeError,
+            `invalid status code ${code}`,
+            true,
+            1002,
+            'WS_ERR_INVALID_CLOSE_CODE'
+          );
+
+          cb(error);
+          return;
+        }
+
+        const buf = new FastBuffer(
+          data.buffer,
+          data.byteOffset + 2,
+          data.length - 2
+        );
+
+        if (!this._skipUTF8Validation && !isValidUTF8(buf)) {
+          const error = this.createError(
+            Error,
+            'invalid UTF-8 sequence',
+            true,
+            1007,
+            'WS_ERR_INVALID_UTF8'
+          );
+
+          cb(error);
+          return;
+        }
+
+        this._loop = false;
+        this.emit('conclude', code, buf);
+        this.end();
+      }
+
+      this._state = GET_INFO;
+      return;
+    }
+
+    if (this._allowSynchronousEvents) {
+      this.emit(this._opcode === 0x09 ? 'ping' : 'pong', data);
+      this._state = GET_INFO;
+    } else {
+      this._state = DEFER_EVENT;
+      setImmediate(() => {
+        this.emit(this._opcode === 0x09 ? 'ping' : 'pong', data);
+        this._state = GET_INFO;
+        this.startLoop(cb);
+      });
+    }
+  }
+
+  /**
+   * Builds an error object.
+   *
+   * @param {function(new:Error|RangeError)} ErrorCtor The error constructor
+   * @param {String} message The error message
+   * @param {Boolean} prefix Specifies whether or not to add a default prefix to
+   *     `message`
+   * @param {Number} statusCode The status code
+   * @param {String} errorCode The exposed error code
+   * @return {(Error|RangeError)} The error
+   * @private
+   */
+  createError(ErrorCtor, message, prefix, statusCode, errorCode) {
+    this._loop = false;
+    this._errored = true;
+
+    const err = new ErrorCtor(
+      prefix ? `Invalid WebSocket frame: ${message}` : message
+    );
+
+    Error.captureStackTrace(err, this.createError);
+    err.code = errorCode;
+    err[kStatusCode] = statusCode;
+    return err;
+  }
+}
+
+module.exports = Receiver;

engine/ds-screencast/node_modules/ws/lib/sender.js

@@ -0,0 +1,602 @@
+/* eslint no-unused-vars: ["error", { "varsIgnorePattern": "^Duplex" }] */
+
+'use strict';
+
+const { Duplex } = require('stream');
+const { randomFillSync } = require('crypto');
+
+const PerMessageDeflate = require('./permessage-deflate');
+const { EMPTY_BUFFER, kWebSocket, NOOP } = require('./constants');
+const { isBlob, isValidStatusCode } = require('./validation');
+const { mask: applyMask, toBuffer } = require('./buffer-util');
+
+const kByteLength = Symbol('kByteLength');
+const maskBuffer = Buffer.alloc(4);
+const RANDOM_POOL_SIZE = 8 * 1024;
+let randomPool;
+let randomPoolPointer = RANDOM_POOL_SIZE;
+
+const DEFAULT = 0;
+const DEFLATING = 1;
+const GET_BLOB_DATA = 2;
+
+/**
+ * HyBi Sender implementation.
+ */
+class Sender {
+  /**
+   * Creates a Sender instance.
+   *
+   * @param {Duplex} socket The connection socket
+   * @param {Object} [extensions] An object containing the negotiated extensions
+   * @param {Function} [generateMask] The function used to generate the masking
+   *     key
+   */
+  constructor(socket, extensions, generateMask) {
+    this._extensions = extensions || {};
+
+    if (generateMask) {
+      this._generateMask = generateMask;
+      this._maskBuffer = Buffer.alloc(4);
+    }
+
+    this._socket = socket;
+
+    this._firstFragment = true;
+    this._compress = false;
+
+    this._bufferedBytes = 0;
+    this._queue = [];
+    this._state = DEFAULT;
+    this.onerror = NOOP;
+    this[kWebSocket] = undefined;
+  }
+
+  /**
+   * Frames a piece of data according to the HyBi WebSocket protocol.
+   *
+   * @param {(Buffer|String)} data The data to frame
+   * @param {Object} options Options object
+   * @param {Boolean} [options.fin=false] Specifies whether or not to set the
+   *     FIN bit
+   * @param {Function} [options.generateMask] The function used to generate the
+   *     masking key
+   * @param {Boolean} [options.mask=false] Specifies whether or not to mask
+   *     `data`
+   * @param {Buffer} [options.maskBuffer] The buffer used to store the masking
+   *     key
+   * @param {Number} options.opcode The opcode
+   * @param {Boolean} [options.readOnly=false] Specifies whether `data` can be
+   *     modified
+   * @param {Boolean} [options.rsv1=false] Specifies whether or not to set the
+   *     RSV1 bit
+   * @return {(Buffer|String)[]} The framed data
+   * @public
+   */
+  static frame(data, options) {
+    let mask;
+    let merge = false;
+    let offset = 2;
+    let skipMasking = false;
+
+    if (options.mask) {
+      mask = options.maskBuffer || maskBuffer;
+
+      if (options.generateMask) {
+        options.generateMask(mask);
+      } else {
+        if (randomPoolPointer === RANDOM_POOL_SIZE) {
+          /* istanbul ignore else  */
+          if (randomPool === undefined) {
+            //
+            // This is lazily initialized because server-sent frames must not
+            // be masked so it may never be used.
+            //
+            randomPool = Buffer.alloc(RANDOM_POOL_SIZE);
+          }
+
+          randomFillSync(randomPool, 0, RANDOM_POOL_SIZE);
+          randomPoolPointer = 0;
+        }
+
+        mask[0] = randomPool[randomPoolPointer++];
+        mask[1] = randomPool[randomPoolPointer++];
+        mask[2] = randomPool[randomPoolPointer++];
+        mask[3] = randomPool[randomPoolPointer++];
+      }
+
+      skipMasking = (mask[0] | mask[1] | mask[2] | mask[3]) === 0;
+      offset = 6;
+    }
+
+    let dataLength;
+
+    if (typeof data === 'string') {
+      if (
+        (!options.mask || skipMasking) &&
+        options[kByteLength] !== undefined
+      ) {
+        dataLength = options[kByteLength];
+      } else {
+        data = Buffer.from(data);
+        dataLength = data.length;
+      }
+    } else {
+      dataLength = data.length;
+      merge = options.mask && options.readOnly && !skipMasking;
+    }
+
+    let payloadLength = dataLength;
+
+    if (dataLength >= 65536) {
+      offset += 8;
+      payloadLength = 127;
+    } else if (dataLength > 125) {
+      offset += 2;
+      payloadLength = 126;
+    }
+
+    const target = Buffer.allocUnsafe(merge ? dataLength + offset : offset);
+
+    target[0] = options.fin ? options.opcode | 0x80 : options.opcode;
+    if (options.rsv1) target[0] |= 0x40;
+
+    target[1] = payloadLength;
+
+    if (payloadLength === 126) {
+      target.writeUInt16BE(dataLength, 2);
+    } else if (payloadLength === 127) {
+      target[2] = target[3] = 0;
+      target.writeUIntBE(dataLength, 4, 6);
+    }
+
+    if (!options.mask) return [target, data];
+
+    target[1] |= 0x80;
+    target[offset - 4] = mask[0];
+    target[offset - 3] = mask[1];
+    target[offset - 2] = mask[2];
+    target[offset - 1] = mask[3];
+
+    if (skipMasking) return [target, data];
+
+    if (merge) {
+      applyMask(data, mask, target, offset, dataLength);
+      return [target];
+    }
+
+    applyMask(data, mask, data, 0, dataLength);
+    return [target, data];
+  }
+
+  /**
+   * Sends a close message to the other peer.
+   *
+   * @param {Number} [code] The status code component of the body
+   * @param {(String|Buffer)} [data] The message component of the body
+   * @param {Boolean} [mask=false] Specifies whether or not to mask the message
+   * @param {Function} [cb] Callback
+   * @public
+   */
+  close(code, data, mask, cb) {
+    let buf;
+
+    if (code === undefined) {
+      buf = EMPTY_BUFFER;
+    } else if (typeof code !== 'number' || !isValidStatusCode(code)) {
+      throw new TypeError('First argument must be a valid error code number');
+    } else if (data === undefined || !data.length) {
+      buf = Buffer.allocUnsafe(2);
+      buf.writeUInt16BE(code, 0);
+    } else {
+      const length = Buffer.byteLength(data);
+
+      if (length > 123) {
+        throw new RangeError('The message must not be greater than 123 bytes');
+      }
+
+      buf = Buffer.allocUnsafe(2 + length);
+      buf.writeUInt16BE(code, 0);
+
+      if (typeof data === 'string') {
+        buf.write(data, 2);
+      } else {
+        buf.set(data, 2);
+      }
+    }
+
+    const options = {
+      [kByteLength]: buf.length,
+      fin: true,
+      generateMask: this._generateMask,
+      mask,
+      maskBuffer: this._maskBuffer,
+      opcode: 0x08,
+      readOnly: false,
+      rsv1: false
+    };
+
+    if (this._state !== DEFAULT) {
+      this.enqueue([this.dispatch, buf, false, options, cb]);
+    } else {
+      this.sendFrame(Sender.frame(buf, options), cb);
+    }
+  }
+
+  /**
+   * Sends a ping message to the other peer.
+   *
+   * @param {*} data The message to send
+   * @param {Boolean} [mask=false] Specifies whether or not to mask `data`
+   * @param {Function} [cb] Callback
+   * @public
+   */
+  ping(data, mask, cb) {
+    let byteLength;
+    let readOnly;
+
+    if (typeof data === 'string') {
+      byteLength = Buffer.byteLength(data);
+      readOnly = false;
+    } else if (isBlob(data)) {
+      byteLength = data.size;
+      readOnly = false;
+    } else {
+      data = toBuffer(data);
+      byteLength = data.length;
+      readOnly = toBuffer.readOnly;
+    }
+
+    if (byteLength > 125) {
+      throw new RangeError('The data size must not be greater than 125 bytes');
+    }
+
+    const options = {
+      [kByteLength]: byteLength,
+      fin: true,
+      generateMask: this._generateMask,
+      mask,
+      maskBuffer: this._maskBuffer,
+      opcode: 0x09,
+      readOnly,
+      rsv1: false
+    };
+
+    if (isBlob(data)) {
+      if (this._state !== DEFAULT) {
+        this.enqueue([this.getBlobData, data, false, options, cb]);
+      } else {
+        this.getBlobData(data, false, options, cb);
+      }
+    } else if (this._state !== DEFAULT) {
+      this.enqueue([this.dispatch, data, false, options, cb]);
+    } else {
+      this.sendFrame(Sender.frame(data, options), cb);
+    }
+  }
+
+  /**
+   * Sends a pong message to the other peer.
+   *
+   * @param {*} data The message to send
+   * @param {Boolean} [mask=false] Specifies whether or not to mask `data`
+   * @param {Function} [cb] Callback
+   * @public
+   */
+  pong(data, mask, cb) {
+    let byteLength;
+    let readOnly;
+
+    if (typeof data === 'string') {
+      byteLength = Buffer.byteLength(data);
+      readOnly = false;
+    } else if (isBlob(data)) {
+      byteLength = data.size;
+      readOnly = false;
+    } else {
+      data = toBuffer(data);
+      byteLength = data.length;
+      readOnly = toBuffer.readOnly;
+    }
+
+    if (byteLength > 125) {
+      throw new RangeError('The data size must not be greater than 125 bytes');
+    }
+
+    const options = {
+      [kByteLength]: byteLength,
+      fin: true,
+      generateMask: this._generateMask,
+      mask,
+      maskBuffer: this._maskBuffer,
+      opcode: 0x0a,
+      readOnly,
+      rsv1: false
+    };
+
+    if (isBlob(data)) {
+      if (this._state !== DEFAULT) {
+        this.enqueue([this.getBlobData, data, false, options, cb]);
+      } else {
+        this.getBlobData(data, false, options, cb);
+      }
+    } else if (this._state !== DEFAULT) {
+      this.enqueue([this.dispatch, data, false, options, cb]);
+    } else {
+      this.sendFrame(Sender.frame(data, options), cb);
+    }
+  }
+
+  /**
+   * Sends a data message to the other peer.
+   *
+   * @param {*} data The message to send
+   * @param {Object} options Options object
+   * @param {Boolean} [options.binary=false] Specifies whether `data` is binary
+   *     or text
+   * @param {Boolean} [options.compress=false] Specifies whether or not to
+   *     compress `data`
+   * @param {Boolean} [options.fin=false] Specifies whether the fragment is the
+   *     last one
+   * @param {Boolean} [options.mask=false] Specifies whether or not to mask
+   *     `data`
+   * @param {Function} [cb] Callback
+   * @public
+   */
+  send(data, options, cb) {
+    const perMessageDeflate = this._extensions[PerMessageDeflate.extensionName];
+    let opcode = options.binary ? 2 : 1;
+    let rsv1 = options.compress;
+
+    let byteLength;
+    let readOnly;
+
+    if (typeof data === 'string') {
+      byteLength = Buffer.byteLength(data);
+      readOnly = false;
+    } else if (isBlob(data)) {
+      byteLength = data.size;
+      readOnly = false;
+    } else {
+      data = toBuffer(data);
+      byteLength = data.length;
+      readOnly = toBuffer.readOnly;
+    }
+
+    if (this._firstFragment) {
+      this._firstFragment = false;
+      if (
+        rsv1 &&
+        perMessageDeflate &&
+        perMessageDeflate.params[
+          perMessageDeflate._isServer
+            ? 'server_no_context_takeover'
+            : 'client_no_context_takeover'
+        ]
+      ) {
+        rsv1 = byteLength >= perMessageDeflate._threshold;
+      }
+      this._compress = rsv1;
+    } else {
+      rsv1 = false;
+      opcode = 0;
+    }
+
+    if (options.fin) this._firstFragment = true;
+
+    const opts = {
+      [kByteLength]: byteLength,
+      fin: options.fin,
+      generateMask: this._generateMask,
+      mask: options.mask,
+      maskBuffer: this._maskBuffer,
+      opcode,
+      readOnly,
+      rsv1
+    };
+
+    if (isBlob(data)) {
+      if (this._state !== DEFAULT) {
+        this.enqueue([this.getBlobData, data, this._compress, opts, cb]);
+      } else {
+        this.getBlobData(data, this._compress, opts, cb);
+      }
+    } else if (this._state !== DEFAULT) {
+      this.enqueue([this.dispatch, data, this._compress, opts, cb]);
+    } else {
+      this.dispatch(data, this._compress, opts, cb);
+    }
+  }
+
+  /**
+   * Gets the contents of a blob as binary data.
+   *
+   * @param {Blob} blob The blob
+   * @param {Boolean} [compress=false] Specifies whether or not to compress
+   *     the data
+   * @param {Object} options Options object
+   * @param {Boolean} [options.fin=false] Specifies whether or not to set the
+   *     FIN bit
+   * @param {Function} [options.generateMask] The function used to generate the
+   *     masking key
+   * @param {Boolean} [options.mask=false] Specifies whether or not to mask
+   *     `data`
+   * @param {Buffer} [options.maskBuffer] The buffer used to store the masking
+   *     key
+   * @param {Number} options.opcode The opcode
+   * @param {Boolean} [options.readOnly=false] Specifies whether `data` can be
+   *     modified
+   * @param {Boolean} [options.rsv1=false] Specifies whether or not to set the
+   *     RSV1 bit
+   * @param {Function} [cb] Callback
+   * @private
+   */
+  getBlobData(blob, compress, options, cb) {
+    this._bufferedBytes += options[kByteLength];
+    this._state = GET_BLOB_DATA;
+
+    blob
+      .arrayBuffer()
+      .then((arrayBuffer) => {
+        if (this._socket.destroyed) {
+          const err = new Error(
+            'The socket was closed while the blob was being read'
+          );
+
+          //
+          // `callCallbacks` is called in the next tick to ensure that errors
+          // that might be thrown in the callbacks behave like errors thrown
+          // outside the promise chain.
+          //
+          process.nextTick(callCallbacks, this, err, cb);
+          return;
+        }
+
+        this._bufferedBytes -= options[kByteLength];
+        const data = toBuffer(arrayBuffer);
+
+        if (!compress) {
+          this._state = DEFAULT;
+          this.sendFrame(Sender.frame(data, options), cb);
+          this.dequeue();
+        } else {
+          this.dispatch(data, compress, options, cb);
+        }
+      })
+      .catch((err) => {
+        //
+        // `onError` is called in the next tick for the same reason that
+        // `callCallbacks` above is.
+        //
+        process.nextTick(onError, this, err, cb);
+      });
+  }
+
+  /**
+   * Dispatches a message.
+   *
+   * @param {(Buffer|String)} data The message to send
+   * @param {Boolean} [compress=false] Specifies whether or not to compress
+   *     `data`
+   * @param {Object} options Options object
+   * @param {Boolean} [options.fin=false] Specifies whether or not to set the
+   *     FIN bit
+   * @param {Function} [options.generateMask] The function used to generate the
+   *     masking key
+   * @param {Boolean} [options.mask=false] Specifies whether or not to mask
+   *     `data`
+   * @param {Buffer} [options.maskBuffer] The buffer used to store the masking
+   *     key
+   * @param {Number} options.opcode The opcode
+   * @param {Boolean} [options.readOnly=false] Specifies whether `data` can be
+   *     modified
+   * @param {Boolean} [options.rsv1=false] Specifies whether or not to set the
+   *     RSV1 bit
+   * @param {Function} [cb] Callback
+   * @private
+   */
+  dispatch(data, compress, options, cb) {
+    if (!compress) {
+      this.sendFrame(Sender.frame(data, options), cb);
+      return;
+    }
+
+    const perMessageDeflate = this._extensions[PerMessageDeflate.extensionName];
+
+    this._bufferedBytes += options[kByteLength];
+    this._state = DEFLATING;
+    perMessageDeflate.compress(data, options.fin, (_, buf) => {
+      if (this._socket.destroyed) {
+        const err = new Error(
+          'The socket was closed while data was being compressed'
+        );
+
+        callCallbacks(this, err, cb);
+        return;
+      }
+
+      this._bufferedBytes -= options[kByteLength];
+      this._state = DEFAULT;
+      options.readOnly = false;
+      this.sendFrame(Sender.frame(buf, options), cb);
+      this.dequeue();
+    });
+  }
+
+  /**
+   * Executes queued send operations.
+   *
+   * @private
+   */
+  dequeue() {
+    while (this._state === DEFAULT && this._queue.length) {
+      const params = this._queue.shift();
+
+      this._bufferedBytes -= params[3][kByteLength];
+      Reflect.apply(params[0], this, params.slice(1));
+    }
+  }
+
+  /**
+   * Enqueues a send operation.
+   *
+   * @param {Array} params Send operation parameters.
+   * @private
+   */
+  enqueue(params) {
+    this._bufferedBytes += params[3][kByteLength];
+    this._queue.push(params);
+  }
+
+  /**
+   * Sends a frame.
+   *
+   * @param {(Buffer | String)[]} list The frame to send
+   * @param {Function} [cb] Callback
+   * @private
+   */
+  sendFrame(list, cb) {
+    if (list.length === 2) {
+      this._socket.cork();
+      this._socket.write(list[0]);
+      this._socket.write(list[1], cb);
+      this._socket.uncork();
+    } else {
+      this._socket.write(list[0], cb);
+    }
+  }
+}
+
+module.exports = Sender;
+
+/**
+ * Calls queued callbacks with an error.
+ *
+ * @param {Sender} sender The `Sender` instance
+ * @param {Error} err The error to call the callbacks with
+ * @param {Function} [cb] The first callback
+ * @private
+ */
+function callCallbacks(sender, err, cb) {
+  if (typeof cb === 'function') cb(err);
+
+  for (let i = 0; i < sender._queue.length; i++) {
+    const params = sender._queue[i];
+    const callback = params[params.length - 1];
+
+    if (typeof callback === 'function') callback(err);
+  }
+}
+
+/**
+ * Handles a `Sender` error.
+ *
+ * @param {Sender} sender The `Sender` instance
+ * @param {Error} err The error
+ * @param {Function} [cb] The first pending callback
+ * @private
+ */
+function onError(sender, err, cb) {
+  callCallbacks(sender, err, cb);
+  sender.onerror(err);
+}

engine/ds-screencast/node_modules/ws/lib/stream.js

@@ -0,0 +1,161 @@
+/* eslint no-unused-vars: ["error", { "varsIgnorePattern": "^WebSocket$" }] */
+'use strict';
+
+const WebSocket = require('./websocket');
+const { Duplex } = require('stream');
+
+/**
+ * Emits the `'close'` event on a stream.
+ *
+ * @param {Duplex} stream The stream.
+ * @private
+ */
+function emitClose(stream) {
+  stream.emit('close');
+}
+
+/**
+ * The listener of the `'end'` event.
+ *
+ * @private
+ */
+function duplexOnEnd() {
+  if (!this.destroyed && this._writableState.finished) {
+    this.destroy();
+  }
+}
+
+/**
+ * The listener of the `'error'` event.
+ *
+ * @param {Error} err The error
+ * @private
+ */
+function duplexOnError(err) {
+  this.removeListener('error', duplexOnError);
+  this.destroy();
+  if (this.listenerCount('error') === 0) {
+    // Do not suppress the throwing behavior.
+    this.emit('error', err);
+  }
+}
+
+/**
+ * Wraps a `WebSocket` in a duplex stream.
+ *
+ * @param {WebSocket} ws The `WebSocket` to wrap
+ * @param {Object} [options] The options for the `Duplex` constructor
+ * @return {Duplex} The duplex stream
+ * @public
+ */
+function createWebSocketStream(ws, options) {
+  let terminateOnDestroy = true;
+
+  const duplex = new Duplex({
+    ...options,
+    autoDestroy: false,
+    emitClose: false,
+    objectMode: false,
+    writableObjectMode: false
+  });
+
+  ws.on('message', function message(msg, isBinary) {
+    const data =
+      !isBinary && duplex._readableState.objectMode ? msg.toString() : msg;
+
+    if (!duplex.push(data)) ws.pause();
+  });
+
+  ws.once('error', function error(err) {
+    if (duplex.destroyed) return;
+
+    // Prevent `ws.terminate()` from being called by `duplex._destroy()`.
+    //
+    // - If the `'error'` event is emitted before the `'open'` event, then
+    //   `ws.terminate()` is a noop as no socket is assigned.
+    // - Otherwise, the error is re-emitted by the listener of the `'error'`
+    //   event of the `Receiver` object. The listener already closes the
+    //   connection by calling `ws.close()`. This allows a close frame to be
+    //   sent to the other peer. If `ws.terminate()` is called right after this,
+    //   then the close frame might not be sent.
+    terminateOnDestroy = false;
+    duplex.destroy(err);
+  });
+
+  ws.once('close', function close() {
+    if (duplex.destroyed) return;
+
+    duplex.push(null);
+  });
+
+  duplex._destroy = function (err, callback) {
+    if (ws.readyState === ws.CLOSED) {
+      callback(err);
+      process.nextTick(emitClose, duplex);
+      return;
+    }
+
+    let called = false;
+
+    ws.once('error', function error(err) {
+      called = true;
+      callback(err);
+    });
+
+    ws.once('close', function close() {
+      if (!called) callback(err);
+      process.nextTick(emitClose, duplex);
+    });
+
+    if (terminateOnDestroy) ws.terminate();
+  };
+
+  duplex._final = function (callback) {
+    if (ws.readyState === ws.CONNECTING) {
+      ws.once('open', function open() {
+        duplex._final(callback);
+      });
+      return;
+    }
+
+    // If the value of the `_socket` property is `null` it means that `ws` is a
+    // client websocket and the handshake failed. In fact, when this happens, a
+    // socket is never assigned to the websocket. Wait for the `'error'` event
+    // that will be emitted by the websocket.
+    if (ws._socket === null) return;
+
+    if (ws._socket._writableState.finished) {
+      callback();
+      if (duplex._readableState.endEmitted) duplex.destroy();
+    } else {
+      ws._socket.once('finish', function finish() {
+        // `duplex` is not destroyed here because the `'end'` event will be
+        // emitted on `duplex` after this `'finish'` event. The EOF signaling
+        // `null` chunk is, in fact, pushed when the websocket emits `'close'`.
+        callback();
+      });
+      ws.close();
+    }
+  };
+
+  duplex._read = function () {
+    if (ws.isPaused) ws.resume();
+  };
+
+  duplex._write = function (chunk, encoding, callback) {
+    if (ws.readyState === ws.CONNECTING) {
+      ws.once('open', function open() {
+        duplex._write(chunk, encoding, callback);
+      });
+      return;
+    }
+
+    ws.send(chunk, callback);
+  };
+
+  duplex.on('end', duplexOnEnd);
+  duplex.on('error', duplexOnError);
+  return duplex;
+}
+
+module.exports = createWebSocketStream;

engine/ds-screencast/node_modules/ws/lib/subprotocol.js

@@ -0,0 +1,62 @@
+'use strict';
+
+const { tokenChars } = require('./validation');
+
+/**
+ * Parses the `Sec-WebSocket-Protocol` header into a set of subprotocol names.
+ *
+ * @param {String} header The field value of the header
+ * @return {Set} The subprotocol names
+ * @public
+ */
+function parse(header) {
+  const protocols = new Set();
+  let start = -1;
+  let end = -1;
+  let i = 0;
+
+  for (i; i < header.length; i++) {
+    const code = header.charCodeAt(i);
+
+    if (end === -1 && tokenChars[code] === 1) {
+      if (start === -1) start = i;
+    } else if (
+      i !== 0 &&
+      (code === 0x20 /* ' ' */ || code === 0x09) /* '\t' */
+    ) {
+      if (end === -1 && start !== -1) end = i;
+    } else if (code === 0x2c /* ',' */) {
+      if (start === -1) {
+        throw new SyntaxError(`Unexpected character at index ${i}`);
+      }
+
+      if (end === -1) end = i;
+
+      const protocol = header.slice(start, end);
+
+      if (protocols.has(protocol)) {
+        throw new SyntaxError(`The "${protocol}" subprotocol is duplicated`);
+      }
+
+      protocols.add(protocol);
+      start = end = -1;
+    } else {
+      throw new SyntaxError(`Unexpected character at index ${i}`);
+    }
+  }
+
+  if (start === -1 || end !== -1) {
+    throw new SyntaxError('Unexpected end of input');
+  }
+
+  const protocol = header.slice(start, i);
+
+  if (protocols.has(protocol)) {
+    throw new SyntaxError(`The "${protocol}" subprotocol is duplicated`);
+  }
+
+  protocols.add(protocol);
+  return protocols;
+}
+
+module.exports = { parse };

engine/ds-screencast/node_modules/ws/lib/validation.js

@@ -0,0 +1,152 @@
+'use strict';
+
+const { isUtf8 } = require('buffer');
+
+const { hasBlob } = require('./constants');
+
+//
+// Allowed token characters:
+//
+// '!', '#', '$', '%', '&', ''', '*', '+', '-',
+// '.', 0-9, A-Z, '^', '_', '`', a-z, '|', '~'
+//
+// tokenChars[32] === 0 // ' '
+// tokenChars[33] === 1 // '!'
+// tokenChars[34] === 0 // '"'
+// ...
+//
+// prettier-ignore
+const tokenChars = [
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 0 - 15
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 16 - 31
+  0, 1, 0, 1, 1, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 0, // 32 - 47
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, // 48 - 63
+  0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 64 - 79
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, // 80 - 95
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 96 - 111
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0 // 112 - 127
+];
+
+/**
+ * Checks if a status code is allowed in a close frame.
+ *
+ * @param {Number} code The status code
+ * @return {Boolean} `true` if the status code is valid, else `false`
+ * @public
+ */
+function isValidStatusCode(code) {
+  return (
+    (code >= 1000 &&
+      code <= 1014 &&
+      code !== 1004 &&
+      code !== 1005 &&
+      code !== 1006) ||
+    (code >= 3000 && code <= 4999)
+  );
+}
+
+/**
+ * Checks if a given buffer contains only correct UTF-8.
+ * Ported from https://www.cl.cam.ac.uk/%7Emgk25/ucs/utf8_check.c by
+ * Markus Kuhn.
+ *
+ * @param {Buffer} buf The buffer to check
+ * @return {Boolean} `true` if `buf` contains only correct UTF-8, else `false`
+ * @public
+ */
+function _isValidUTF8(buf) {
+  const len = buf.length;
+  let i = 0;
+
+  while (i < len) {
+    if ((buf[i] & 0x80) === 0) {
+      // 0xxxxxxx
+      i++;
+    } else if ((buf[i] & 0xe0) === 0xc0) {
+      // 110xxxxx 10xxxxxx
+      if (
+        i + 1 === len ||
+        (buf[i + 1] & 0xc0) !== 0x80 ||
+        (buf[i] & 0xfe) === 0xc0 // Overlong
+      ) {
+        return false;
+      }
+
+      i += 2;
+    } else if ((buf[i] & 0xf0) === 0xe0) {
+      // 1110xxxx 10xxxxxx 10xxxxxx
+      if (
+        i + 2 >= len ||
+        (buf[i + 1] & 0xc0) !== 0x80 ||
+        (buf[i + 2] & 0xc0) !== 0x80 ||
+        (buf[i] === 0xe0 && (buf[i + 1] & 0xe0) === 0x80) || // Overlong
+        (buf[i] === 0xed && (buf[i + 1] & 0xe0) === 0xa0) // Surrogate (U+D800 - U+DFFF)
+      ) {
+        return false;
+      }
+
+      i += 3;
+    } else if ((buf[i] & 0xf8) === 0xf0) {
+      // 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
+      if (
+        i + 3 >= len ||
+        (buf[i + 1] & 0xc0) !== 0x80 ||
+        (buf[i + 2] & 0xc0) !== 0x80 ||
+        (buf[i + 3] & 0xc0) !== 0x80 ||
+        (buf[i] === 0xf0 && (buf[i + 1] & 0xf0) === 0x80) || // Overlong
+        (buf[i] === 0xf4 && buf[i + 1] > 0x8f) ||
+        buf[i] > 0xf4 // > U+10FFFF
+      ) {
+        return false;
+      }
+
+      i += 4;
+    } else {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+/**
+ * Determines whether a value is a `Blob`.
+ *
+ * @param {*} value The value to be tested
+ * @return {Boolean} `true` if `value` is a `Blob`, else `false`
+ * @private
+ */
+function isBlob(value) {
+  return (
+    hasBlob &&
+    typeof value === 'object' &&
+    typeof value.arrayBuffer === 'function' &&
+    typeof value.type === 'string' &&
+    typeof value.stream === 'function' &&
+    (value[Symbol.toStringTag] === 'Blob' ||
+      value[Symbol.toStringTag] === 'File')
+  );
+}
+
+module.exports = {
+  isBlob,
+  isValidStatusCode,
+  isValidUTF8: _isValidUTF8,
+  tokenChars
+};
+
+if (isUtf8) {
+  module.exports.isValidUTF8 = function (buf) {
+    return buf.length < 24 ? _isValidUTF8(buf) : isUtf8(buf);
+  };
+} /* istanbul ignore else  */ else if (!process.env.WS_NO_UTF_8_VALIDATE) {
+  try {
+    const isValidUTF8 = require('utf-8-validate');
+
+    module.exports.isValidUTF8 = function (buf) {
+      return buf.length < 32 ? _isValidUTF8(buf) : isValidUTF8(buf);
+    };
+  } catch (e) {
+    // Continue regardless of the error.
+  }
+}

engine/ds-screencast/node_modules/ws/lib/websocket-server.js

@@ -0,0 +1,554 @@
+/* eslint no-unused-vars: ["error", { "varsIgnorePattern": "^Duplex$", "caughtErrors": "none" }] */
+
+'use strict';
+
+const EventEmitter = require('events');
+const http = require('http');
+const { Duplex } = require('stream');
+const { createHash } = require('crypto');
+
+const extension = require('./extension');
+const PerMessageDeflate = require('./permessage-deflate');
+const subprotocol = require('./subprotocol');
+const WebSocket = require('./websocket');
+const { CLOSE_TIMEOUT, GUID, kWebSocket } = require('./constants');
+
+const keyRegex = /^[+/0-9A-Za-z]{22}==$/;
+
+const RUNNING = 0;
+const CLOSING = 1;
+const CLOSED = 2;
+
+/**
+ * Class representing a WebSocket server.
+ *
+ * @extends EventEmitter
+ */
+class WebSocketServer extends EventEmitter {
+  /**
+   * Create a `WebSocketServer` instance.
+   *
+   * @param {Object} options Configuration options
+   * @param {Boolean} [options.allowSynchronousEvents=true] Specifies whether
+   *     any of the `'message'`, `'ping'`, and `'pong'` events can be emitted
+   *     multiple times in the same tick
+   * @param {Boolean} [options.autoPong=true] Specifies whether or not to
+   *     automatically send a pong in response to a ping
+   * @param {Number} [options.backlog=511] The maximum length of the queue of
+   *     pending connections
+   * @param {Boolean} [options.clientTracking=true] Specifies whether or not to
+   *     track clients
+   * @param {Number} [options.closeTimeout=30000] Duration in milliseconds to
+   *     wait for the closing handshake to finish after `websocket.close()` is
+   *     called
+   * @param {Function} [options.handleProtocols] A hook to handle protocols
+   * @param {String} [options.host] The hostname where to bind the server
+   * @param {Number} [options.maxPayload=104857600] The maximum allowed message
+   *     size
+   * @param {Boolean} [options.noServer=false] Enable no server mode
+   * @param {String} [options.path] Accept only connections matching this path
+   * @param {(Boolean|Object)} [options.perMessageDeflate=false] Enable/disable
+   *     permessage-deflate
+   * @param {Number} [options.port] The port where to bind the server
+   * @param {(http.Server|https.Server)} [options.server] A pre-created HTTP/S
+   *     server to use
+   * @param {Boolean} [options.skipUTF8Validation=false] Specifies whether or
+   *     not to skip UTF-8 validation for text and close messages
+   * @param {Function} [options.verifyClient] A hook to reject connections
+   * @param {Function} [options.WebSocket=WebSocket] Specifies the `WebSocket`
+   *     class to use. It must be the `WebSocket` class or class that extends it
+   * @param {Function} [callback] A listener for the `listening` event
+   */
+  constructor(options, callback) {
+    super();
+
+    options = {
+      allowSynchronousEvents: true,
+      autoPong: true,
+      maxPayload: 100 * 1024 * 1024,
+      skipUTF8Validation: false,
+      perMessageDeflate: false,
+      handleProtocols: null,
+      clientTracking: true,
+      closeTimeout: CLOSE_TIMEOUT,
+      verifyClient: null,
+      noServer: false,
+      backlog: null, // use default (511 as implemented in net.js)
+      server: null,
+      host: null,
+      path: null,
+      port: null,
+      WebSocket,
+      ...options
+    };
+
+    if (
+      (options.port == null && !options.server && !options.noServer) ||
+      (options.port != null && (options.server || options.noServer)) ||
+      (options.server && options.noServer)
+    ) {
+      throw new TypeError(
+        'One and only one of the "port", "server", or "noServer" options ' +
+          'must be specified'
+      );
+    }
+
+    if (options.port != null) {
+      this._server = http.createServer((req, res) => {
+        const body = http.STATUS_CODES[426];
+
+        res.writeHead(426, {
+          'Content-Length': body.length,
+          'Content-Type': 'text/plain'
+        });
+        res.end(body);
+      });
+      this._server.listen(
+        options.port,
+        options.host,
+        options.backlog,
+        callback
+      );
+    } else if (options.server) {
+      this._server = options.server;
+    }
+
+    if (this._server) {
+      const emitConnection = this.emit.bind(this, 'connection');
+
+      this._removeListeners = addListeners(this._server, {
+        listening: this.emit.bind(this, 'listening'),
+        error: this.emit.bind(this, 'error'),
+        upgrade: (req, socket, head) => {
+          this.handleUpgrade(req, socket, head, emitConnection);
+        }
+      });
+    }
+
+    if (options.perMessageDeflate === true) options.perMessageDeflate = {};
+    if (options.clientTracking) {
+      this.clients = new Set();
+      this._shouldEmitClose = false;
+    }
+
+    this.options = options;
+    this._state = RUNNING;
+  }
+
+  /**
+   * Returns the bound address, the address family name, and port of the server
+   * as reported by the operating system if listening on an IP socket.
+   * If the server is listening on a pipe or UNIX domain socket, the name is
+   * returned as a string.
+   *
+   * @return {(Object|String|null)} The address of the server
+   * @public
+   */
+  address() {
+    if (this.options.noServer) {
+      throw new Error('The server is operating in "noServer" mode');
+    }
+
+    if (!this._server) return null;
+    return this._server.address();
+  }
+
+  /**
+   * Stop the server from accepting new connections and emit the `'close'` event
+   * when all existing connections are closed.
+   *
+   * @param {Function} [cb] A one-time listener for the `'close'` event
+   * @public
+   */
+  close(cb) {
+    if (this._state === CLOSED) {
+      if (cb) {
+        this.once('close', () => {
+          cb(new Error('The server is not running'));
+        });
+      }
+
+      process.nextTick(emitClose, this);
+      return;
+    }
+
+    if (cb) this.once('close', cb);
+
+    if (this._state === CLOSING) return;
+    this._state = CLOSING;
+
+    if (this.options.noServer || this.options.server) {
+      if (this._server) {
+        this._removeListeners();
+        this._removeListeners = this._server = null;
+      }
+
+      if (this.clients) {
+        if (!this.clients.size) {
+          process.nextTick(emitClose, this);
+        } else {
+          this._shouldEmitClose = true;
+        }
+      } else {
+        process.nextTick(emitClose, this);
+      }
+    } else {
+      const server = this._server;
+
+      this._removeListeners();
+      this._removeListeners = this._server = null;
+
+      //
+      // The HTTP/S server was created internally. Close it, and rely on its
+      // `'close'` event.
+      //
+      server.close(() => {
+        emitClose(this);
+      });
+    }
+  }
+
+  /**
+   * See if a given request should be handled by this server instance.
+   *
+   * @param {http.IncomingMessage} req Request object to inspect
+   * @return {Boolean} `true` if the request is valid, else `false`
+   * @public
+   */
+  shouldHandle(req) {
+    if (this.options.path) {
+      const index = req.url.indexOf('?');
+      const pathname = index !== -1 ? req.url.slice(0, index) : req.url;
+
+      if (pathname !== this.options.path) return false;
+    }
+
+    return true;
+  }
+
+  /**
+   * Handle a HTTP Upgrade request.
+   *
+   * @param {http.IncomingMessage} req The request object
+   * @param {Duplex} socket The network socket between the server and client
+   * @param {Buffer} head The first packet of the upgraded stream
+   * @param {Function} cb Callback
+   * @public
+   */
+  handleUpgrade(req, socket, head, cb) {
+    socket.on('error', socketOnError);
+
+    const key = req.headers['sec-websocket-key'];
+    const upgrade = req.headers.upgrade;
+    const version = +req.headers['sec-websocket-version'];
+
+    if (req.method !== 'GET') {
+      const message = 'Invalid HTTP method';
+      abortHandshakeOrEmitwsClientError(this, req, socket, 405, message);
+      return;
+    }
+
+    if (upgrade === undefined || upgrade.toLowerCase() !== 'websocket') {
+      const message = 'Invalid Upgrade header';
+      abortHandshakeOrEmitwsClientError(this, req, socket, 400, message);
+      return;
+    }
+
+    if (key === undefined || !keyRegex.test(key)) {
+      const message = 'Missing or invalid Sec-WebSocket-Key header';
+      abortHandshakeOrEmitwsClientError(this, req, socket, 400, message);
+      return;
+    }
+
+    if (version !== 13 && version !== 8) {
+      const message = 'Missing or invalid Sec-WebSocket-Version header';
+      abortHandshakeOrEmitwsClientError(this, req, socket, 400, message, {
+        'Sec-WebSocket-Version': '13, 8'
+      });
+      return;
+    }
+
+    if (!this.shouldHandle(req)) {
+      abortHandshake(socket, 400);
+      return;
+    }
+
+    const secWebSocketProtocol = req.headers['sec-websocket-protocol'];
+    let protocols = new Set();
+
+    if (secWebSocketProtocol !== undefined) {
+      try {
+        protocols = subprotocol.parse(secWebSocketProtocol);
+      } catch (err) {
+        const message = 'Invalid Sec-WebSocket-Protocol header';
+        abortHandshakeOrEmitwsClientError(this, req, socket, 400, message);
+        return;
+      }
+    }
+
+    const secWebSocketExtensions = req.headers['sec-websocket-extensions'];
+    const extensions = {};
+
+    if (
+      this.options.perMessageDeflate &&
+      secWebSocketExtensions !== undefined
+    ) {
+      const perMessageDeflate = new PerMessageDeflate(
+        this.options.perMessageDeflate,
+        true,
+        this.options.maxPayload
+      );
+
+      try {
+        const offers = extension.parse(secWebSocketExtensions);
+
+        if (offers[PerMessageDeflate.extensionName]) {
+          perMessageDeflate.accept(offers[PerMessageDeflate.extensionName]);
+          extensions[PerMessageDeflate.extensionName] = perMessageDeflate;
+        }
+      } catch (err) {
+        const message =
+          'Invalid or unacceptable Sec-WebSocket-Extensions header';
+        abortHandshakeOrEmitwsClientError(this, req, socket, 400, message);
+        return;
+      }
+    }
+
+    //
+    // Optionally call external client verification handler.
+    //
+    if (this.options.verifyClient) {
+      const info = {
+        origin:
+          req.headers[`${version === 8 ? 'sec-websocket-origin' : 'origin'}`],
+        secure: !!(req.socket.authorized || req.socket.encrypted),
+        req
+      };
+
+      if (this.options.verifyClient.length === 2) {
+        this.options.verifyClient(info, (verified, code, message, headers) => {
+          if (!verified) {
+            return abortHandshake(socket, code || 401, message, headers);
+          }
+
+          this.completeUpgrade(
+            extensions,
+            key,
+            protocols,
+            req,
+            socket,
+            head,
+            cb
+          );
+        });
+        return;
+      }
+
+      if (!this.options.verifyClient(info)) return abortHandshake(socket, 401);
+    }
+
+    this.completeUpgrade(extensions, key, protocols, req, socket, head, cb);
+  }
+
+  /**
+   * Upgrade the connection to WebSocket.
+   *
+   * @param {Object} extensions The accepted extensions
+   * @param {String} key The value of the `Sec-WebSocket-Key` header
+   * @param {Set} protocols The subprotocols
+   * @param {http.IncomingMessage} req The request object
+   * @param {Duplex} socket The network socket between the server and client
+   * @param {Buffer} head The first packet of the upgraded stream
+   * @param {Function} cb Callback
+   * @throws {Error} If called more than once with the same socket
+   * @private
+   */
+  completeUpgrade(extensions, key, protocols, req, socket, head, cb) {
+    //
+    // Destroy the socket if the client has already sent a FIN packet.
+    //
+    if (!socket.readable || !socket.writable) return socket.destroy();
+
+    if (socket[kWebSocket]) {
+      throw new Error(
+        'server.handleUpgrade() was called more than once with the same ' +
+          'socket, possibly due to a misconfiguration'
+      );
+    }
+
+    if (this._state > RUNNING) return abortHandshake(socket, 503);
+
+    const digest = createHash('sha1')
+      .update(key + GUID)
+      .digest('base64');
+
+    const headers = [
+      'HTTP/1.1 101 Switching Protocols',
+      'Upgrade: websocket',
+      'Connection: Upgrade',
+      `Sec-WebSocket-Accept: ${digest}`
+    ];
+
+    const ws = new this.options.WebSocket(null, undefined, this.options);
+
+    if (protocols.size) {
+      //
+      // Optionally call external protocol selection handler.
+      //
+      const protocol = this.options.handleProtocols
+        ? this.options.handleProtocols(protocols, req)
+        : protocols.values().next().value;
+
+      if (protocol) {
+        headers.push(`Sec-WebSocket-Protocol: ${protocol}`);
+        ws._protocol = protocol;
+      }
+    }
+
+    if (extensions[PerMessageDeflate.extensionName]) {
+      const params = extensions[PerMessageDeflate.extensionName].params;
+      const value = extension.format({
+        [PerMessageDeflate.extensionName]: [params]
+      });
+      headers.push(`Sec-WebSocket-Extensions: ${value}`);
+      ws._extensions = extensions;
+    }
+
+    //
+    // Allow external modification/inspection of handshake headers.
+    //
+    this.emit('headers', headers, req);
+
+    socket.write(headers.concat('\r\n').join('\r\n'));
+    socket.removeListener('error', socketOnError);
+
+    ws.setSocket(socket, head, {
+      allowSynchronousEvents: this.options.allowSynchronousEvents,
+      maxPayload: this.options.maxPayload,
+      skipUTF8Validation: this.options.skipUTF8Validation
+    });
+
+    if (this.clients) {
+      this.clients.add(ws);
+      ws.on('close', () => {
+        this.clients.delete(ws);
+
+        if (this._shouldEmitClose && !this.clients.size) {
+          process.nextTick(emitClose, this);
+        }
+      });
+    }
+
+    cb(ws, req);
+  }
+}
+
+module.exports = WebSocketServer;
+
+/**
+ * Add event listeners on an `EventEmitter` using a map of <event, listener>
+ * pairs.
+ *
+ * @param {EventEmitter} server The event emitter
+ * @param {Object.<String, Function>} map The listeners to add
+ * @return {Function} A function that will remove the added listeners when
+ *     called
+ * @private
+ */
+function addListeners(server, map) {
+  for (const event of Object.keys(map)) server.on(event, map[event]);
+
+  return function removeListeners() {
+    for (const event of Object.keys(map)) {
+      server.removeListener(event, map[event]);
+    }
+  };
+}
+
+/**
+ * Emit a `'close'` event on an `EventEmitter`.
+ *
+ * @param {EventEmitter} server The event emitter
+ * @private
+ */
+function emitClose(server) {
+  server._state = CLOSED;
+  server.emit('close');
+}
+
+/**
+ * Handle socket errors.
+ *
+ * @private
+ */
+function socketOnError() {
+  this.destroy();
+}
+
+/**
+ * Close the connection when preconditions are not fulfilled.
+ *
+ * @param {Duplex} socket The socket of the upgrade request
+ * @param {Number} code The HTTP response status code
+ * @param {String} [message] The HTTP response body
+ * @param {Object} [headers] Additional HTTP response headers
+ * @private
+ */
+function abortHandshake(socket, code, message, headers) {
+  //
+  // The socket is writable unless the user destroyed or ended it before calling
+  // `server.handleUpgrade()` or in the `verifyClient` function, which is a user
+  // error. Handling this does not make much sense as the worst that can happen
+  // is that some of the data written by the user might be discarded due to the
+  // call to `socket.end()` below, which triggers an `'error'` event that in
+  // turn causes the socket to be destroyed.
+  //
+  message = message || http.STATUS_CODES[code];
+  headers = {
+    Connection: 'close',
+    'Content-Type': 'text/html',
+    'Content-Length': Buffer.byteLength(message),
+    ...headers
+  };
+
+  socket.once('finish', socket.destroy);
+
+  socket.end(
+    `HTTP/1.1 ${code} ${http.STATUS_CODES[code]}\r\n` +
+      Object.keys(headers)
+        .map((h) => `${h}: ${headers[h]}`)
+        .join('\r\n') +
+      '\r\n\r\n' +
+      message
+  );
+}
+
+/**
+ * Emit a `'wsClientError'` event on a `WebSocketServer` if there is at least
+ * one listener for it, otherwise call `abortHandshake()`.
+ *
+ * @param {WebSocketServer} server The WebSocket server
+ * @param {http.IncomingMessage} req The request object
+ * @param {Duplex} socket The socket of the upgrade request
+ * @param {Number} code The HTTP response status code
+ * @param {String} message The HTTP response body
+ * @param {Object} [headers] The HTTP response headers
+ * @private
+ */
+function abortHandshakeOrEmitwsClientError(
+  server,
+  req,
+  socket,
+  code,
+  message,
+  headers
+) {
+  if (server.listenerCount('wsClientError')) {
+    const err = new Error(message);
+    Error.captureStackTrace(err, abortHandshakeOrEmitwsClientError);
+
+    server.emit('wsClientError', err, socket, req);
+  } else {
+    abortHandshake(socket, code, message, headers);
+  }
+}

engine/ds-screencast/node_modules/ws/package.json

@@ -0,0 +1,69 @@
+{
+  "name": "ws",
+  "version": "8.19.0",
+  "description": "Simple to use, blazing fast and thoroughly tested websocket client and server for Node.js",
+  "keywords": [
+    "HyBi",
+    "Push",
+    "RFC-6455",
+    "WebSocket",
+    "WebSockets",
+    "real-time"
+  ],
+  "homepage": "https://github.com/websockets/ws",
+  "bugs": "https://github.com/websockets/ws/issues",
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/websockets/ws.git"
+  },
+  "author": "Einar Otto Stangvik <einaros@gmail.com> (http://2x.io)",
+  "license": "MIT",
+  "main": "index.js",
+  "exports": {
+    ".": {
+      "browser": "./browser.js",
+      "import": "./wrapper.mjs",
+      "require": "./index.js"
+    },
+    "./package.json": "./package.json"
+  },
+  "browser": "browser.js",
+  "engines": {
+    "node": ">=10.0.0"
+  },
+  "files": [
+    "browser.js",
+    "index.js",
+    "lib/*.js",
+    "wrapper.mjs"
+  ],
+  "scripts": {
+    "test": "nyc --reporter=lcov --reporter=text mocha --throw-deprecation test/*.test.js",
+    "integration": "mocha --throw-deprecation test/*.integration.js",
+    "lint": "eslint . && prettier --check --ignore-path .gitignore \"**/*.{json,md,yaml,yml}\""
+  },
+  "peerDependencies": {
+    "bufferutil": "^4.0.1",
+    "utf-8-validate": ">=5.0.2"
+  },
+  "peerDependenciesMeta": {
+    "bufferutil": {
+      "optional": true
+    },
+    "utf-8-validate": {
+      "optional": true
+    }
+  },
+  "devDependencies": {
+    "benchmark": "^2.1.4",
+    "bufferutil": "^4.0.1",
+    "eslint": "^9.0.0",
+    "eslint-config-prettier": "^10.0.1",
+    "eslint-plugin-prettier": "^5.0.0",
+    "globals": "^16.0.0",
+    "mocha": "^8.4.0",
+    "nyc": "^15.0.0",
+    "prettier": "^3.0.0",
+    "utf-8-validate": "^6.0.0"
+  }
+}

engine/ds-screencast/node_modules/ws/wrapper.mjs

@@ -0,0 +1,8 @@
+import createWebSocketStream from './lib/stream.js';
+import Receiver from './lib/receiver.js';
+import Sender from './lib/sender.js';
+import WebSocket from './lib/websocket.js';
+import WebSocketServer from './lib/websocket-server.js';
+
+export { createWebSocketStream, Receiver, Sender, WebSocket, WebSocketServer };
+export default WebSocket;

engine/ds-screencast/package-lock.json

@@ -0,0 +1,78 @@
+{
+  "name": "ds-screencast",
+  "version": "1.0.0",
+  "lockfileVersion": 3,
+  "requires": true,
+  "packages": {
+    "": {
+      "name": "ds-screencast",
+      "version": "1.0.0",
+      "license": "ISC",
+      "dependencies": {
+        "chrome-remote-interface": "^0.34.0",
+        "ws": "^8.19.0"
+      }
+    },
+    "node_modules/chrome-remote-interface": {
+      "version": "0.34.0",
+      "resolved": "https://registry.npmjs.org/chrome-remote-interface/-/chrome-remote-interface-0.34.0.tgz",
+      "integrity": "sha512-rTTcTZ3zemx8I+nvBii7d8BAF0Ms8LLEroypfvwwZOwSpyNGLE28nStXyCA6VwGp2YSQfmCrQH21F/E+oBFvMw==",
+      "license": "MIT",
+      "dependencies": {
+        "commander": "2.11.x",
+        "ws": "^7.2.0"
+      },
+      "bin": {
+        "chrome-remote-interface": "bin/client.js"
+      }
+    },
+    "node_modules/chrome-remote-interface/node_modules/ws": {
+      "version": "7.5.10",
+      "resolved": "https://registry.npmjs.org/ws/-/ws-7.5.10.tgz",
+      "integrity": "sha512-+dbF1tHwZpXcbOJdVOkzLDxZP1ailvSxM6ZweXTegylPny803bFhA+vqBYw4s31NSAk4S2Qz+AKXK9a4wkdjcQ==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=8.3.0"
+      },
+      "peerDependencies": {
+        "bufferutil": "^4.0.1",
+        "utf-8-validate": "^5.0.2"
+      },
+      "peerDependenciesMeta": {
+        "bufferutil": {
+          "optional": true
+        },
+        "utf-8-validate": {
+          "optional": true
+        }
+      }
+    },
+    "node_modules/commander": {
+      "version": "2.11.0",
+      "resolved": "https://registry.npmjs.org/commander/-/commander-2.11.0.tgz",
+      "integrity": "sha512-b0553uYA5YAEGgyYIGYROzKQ7X5RAqedkfjiZxwi0kL1g3bOaBNNZfYkzt/CL0umgD5wc9Jec2FbB98CjkMRvQ==",
+      "license": "MIT"
+    },
+    "node_modules/ws": {
+      "version": "8.19.0",
+      "resolved": "https://registry.npmjs.org/ws/-/ws-8.19.0.tgz",
+      "integrity": "sha512-blAT2mjOEIi0ZzruJfIhb3nps74PRWTCz1IjglWEEpQl5XS/UNama6u2/rjFkDDouqr4L67ry+1aGIALViWjDg==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=10.0.0"
+      },
+      "peerDependencies": {
+        "bufferutil": "^4.0.1",
+        "utf-8-validate": ">=5.0.2"
+      },
+      "peerDependenciesMeta": {
+        "bufferutil": {
+          "optional": true
+        },
+        "utf-8-validate": {
+          "optional": true
+        }
+      }
+    }
+  }
+}

engine/ds-screencast/package.json

@@ -0,0 +1,16 @@
+{
+  "name": "ds-screencast",
+  "version": "1.0.0",
+  "main": "index.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "description": "",
+  "dependencies": {
+    "chrome-remote-interface": "^0.34.0",
+    "ws": "^8.19.0"
+  }
+}

engine/ds-stream/src/ds_hub.rs

@@ -0,0 +1,221 @@
+//! DreamStack Hub — ESP-NOW + UDP Signal Sender
+//!
+//! Hub-side transport for Panel IR:
+//!   - UDP: push full IR JSON to panels on port 9200
+//!   - ESP-NOW (via serial bridge): send binary signal frames (<1ms)
+//!
+//! # Architecture
+//!
+//! Since Linux doesn't have native ESP-NOW support, we use an
+//! ESP32-C3 USB dongle as a serial bridge:
+//!
+//! ```text
+//! ┌──────────┐  UART/USB  ┌──────────┐  ESP-NOW  ┌──────────┐
+//! │  ds-hub   │ ─────────► │ C3 bridge │ ────────► │  Panel   │
+//! │  (Rust)   │ ◄───────── │  (dongle) │ ◄──────── │ (ESP32)  │
+//! └──────────┘             └──────────┘            └──────────┘
+//! ```
+//!
+//! For testing without hardware, the hub falls back to UDP-only mode,
+//! which works with the browser previewer over WebSocket.
+
+use std::net::UdpSocket;
+use std::io::{self, Read, Write};
+use std::time::Duration;
+use std::fs;
+use std::path::Path;
+
+/// DreamStack binary frame types (must match ds_espnow.h)
+pub mod frame {
+    pub const DS_NOW_SIG: u8 = 0x20;
+    pub const DS_NOW_SIG_BATCH: u8 = 0x21;
+    pub const DS_NOW_TOUCH: u8 = 0x30;
+    pub const DS_NOW_ACTION: u8 = 0x31;
+    pub const DS_NOW_PING: u8 = 0xFE;
+    pub const DS_NOW_PONG: u8 = 0xFD;
+
+    pub const DS_UDP_IR_PUSH: u8 = 0x40;
+    pub const DS_UDP_IR_FRAG: u8 = 0x41;
+
+    pub const DS_MAGIC: [u8; 2] = [0xD5, 0x7A];
+    pub const DS_UDP_PORT: u16 = 9200;
+}
+
+/// A signal update ready to send.
+#[derive(Debug, Clone)]
+pub struct SignalUpdate {
+    pub id: u16,
+    pub value: i32,
+}
+
+/// Hub transport — sends signals and IR to panels.
+pub struct DsHub {
+    udp: UdpSocket,
+    panel_addr: String,
+    seq: u8,
+    // serial: Option<Box<dyn SerialPort>>,  // For ESP32-C3 bridge (future)
+}
+
+impl DsHub {
+    /// Create a new hub targeting a panel at the given address.
+    ///
+    /// ```rust
+    /// let hub = DsHub::new("192.168.1.100")?;
+    /// hub.push_ir(&ir_json)?;
+    /// hub.send_signal(0, 75)?;
+    /// ```
+    pub fn new(panel_ip: &str) -> io::Result<Self> {
+        let udp = UdpSocket::bind("0.0.0.0:0")?;
+        udp.set_broadcast(true)?;
+        Ok(DsHub {
+            udp,
+            panel_addr: format!("{}:{}", panel_ip, frame::DS_UDP_PORT),
+            seq: 0,
+            // serial: None,
+        })
+    }
+
+    /// Create a hub that broadcasts to all panels on the network.
+    pub fn broadcast() -> io::Result<Self> {
+        let udp = UdpSocket::bind("0.0.0.0:0")?;
+        udp.set_broadcast(true)?;
+        Ok(DsHub {
+            udp,
+            panel_addr: format!("255.255.255.255:{}", frame::DS_UDP_PORT),
+            seq: 0,
+        })
+    }
+
+    /// Push IR JSON to the panel via UDP.
+    /// Fragments if > 1400 bytes (UDP MTU safety margin).
+    pub fn push_ir(&mut self, ir_json: &str) -> io::Result<()> {
+        let data = ir_json.as_bytes();
+
+        if data.len() <= 1400 {
+            // Single packet
+            let mut buf = Vec::with_capacity(4 + data.len());
+            buf.extend_from_slice(&frame::DS_MAGIC);
+            buf.push(frame::DS_UDP_IR_PUSH);
+            buf.push(0); // reserved
+            buf.extend_from_slice(&(data.len() as u16).to_le_bytes());
+            buf.extend_from_slice(data);
+            self.udp.send_to(&buf, &self.panel_addr)?;
+        } else {
+            // Fragment
+            let frag_size = 1400;
+            let total = (data.len() + frag_size - 1) / frag_size;
+            let seq = self.next_seq();
+
+            for i in 0..total {
+                let start = i * frag_size;
+                let end = std::cmp::min(start + frag_size, data.len());
+                let chunk = &data[start..end];
+
+                let mut buf = Vec::with_capacity(6 + chunk.len());
+                buf.extend_from_slice(&frame::DS_MAGIC);
+                buf.push(frame::DS_UDP_IR_FRAG);
+                buf.push(i as u8);       // frag_id
+                buf.push(total as u8);   // frag_total
+                buf.push(seq);           // group seq
+                buf.extend_from_slice(chunk);
+                self.udp.send_to(&buf, &self.panel_addr)?;
+
+                // Small delay between fragments to avoid overwhelming receiver
+                std::thread::sleep(Duration::from_millis(2));
+            }
+        }
+
+        Ok(())
+    }
+
+    /// Send a single signal update via UDP (fallback, ~2ms).
+    /// For sub-1ms, use ESP-NOW via serial bridge.
+    pub fn send_signal(&mut self, id: u16, value: i32) -> io::Result<()> {
+        let buf: [u8; 7] = [
+            frame::DS_NOW_SIG,
+            (id & 0xFF) as u8,
+            ((id >> 8) & 0xFF) as u8,
+            (value & 0xFF) as u8,
+            ((value >> 8) & 0xFF) as u8,
+            ((value >> 16) & 0xFF) as u8,
+            ((value >> 24) & 0xFF) as u8,
+        ];
+        self.udp.send_to(&buf, &self.panel_addr)?;
+        Ok(())
+    }
+
+    /// Send a batch of signal updates in one UDP packet.
+    pub fn send_signal_batch(&mut self, signals: &[SignalUpdate]) -> io::Result<()> {
+        let mut buf = Vec::with_capacity(3 + signals.len() * 6);
+        buf.push(frame::DS_NOW_SIG_BATCH);
+        buf.push(signals.len() as u8);
+        buf.push(self.next_seq());
+
+        for sig in signals {
+            buf.extend_from_slice(&sig.id.to_le_bytes());
+            buf.extend_from_slice(&sig.value.to_le_bytes());
+        }
+
+        self.udp.send_to(&buf, &self.panel_addr)?;
+        Ok(())
+    }
+
+    /// Send a heartbeat ping.
+    pub fn send_ping(&mut self) -> io::Result<()> {
+        let buf = [frame::DS_NOW_PING, self.next_seq()];
+        self.udp.send_to(&buf, &self.panel_addr)?;
+        Ok(())
+    }
+
+    /// Listen for panel responses (pong, action events).
+    /// Blocks for up to `timeout` duration.
+    pub fn recv_event(&self, timeout: Duration) -> io::Result<Option<PanelEvent>> {
+        self.udp.set_read_timeout(Some(timeout))?;
+        let mut buf = [0u8; 256];
+        match self.udp.recv_from(&mut buf) {
+            Ok((len, _addr)) => {
+                if len < 1 { return Ok(None); }
+                match buf[0] {
+                    frame::DS_NOW_PONG => Ok(Some(PanelEvent::Pong(buf[1]))),
+                    frame::DS_NOW_ACTION if len >= 4 => Ok(Some(PanelEvent::Action {
+                        node_id: buf[1],
+                        action: buf[2],
+                    })),
+                    frame::DS_NOW_TOUCH if len >= 8 => {
+                        let x = u16::from_le_bytes([buf[4], buf[5]]);
+                        let y = u16::from_le_bytes([buf[6], buf[7]]);
+                        Ok(Some(PanelEvent::Touch {
+                            node_id: buf[1],
+                            event: buf[2],
+                            x,
+                            y,
+                        }))
+                    }
+                    _ => Ok(None),
+                }
+            }
+            Err(e) if e.kind() == io::ErrorKind::WouldBlock => Ok(None),
+            Err(e) => Err(e),
+        }
+    }
+
+    /// Load IR JSON from a file and push to panel.
+    pub fn push_ir_file(&mut self, path: &Path) -> io::Result<()> {
+        let json = fs::read_to_string(path)?;
+        self.push_ir(&json)
+    }
+
+    fn next_seq(&mut self) -> u8 {
+        let s = self.seq;
+        self.seq = self.seq.wrapping_add(1);
+        s
+    }
+}
+
+/// Events received from a panel.
+#[derive(Debug)]
+pub enum PanelEvent {
+    Pong(u8),
+    Action { node_id: u8, action: u8 },
+    Touch { node_id: u8, event: u8, x: u16, y: u16 },
+}

engine/ds-stream/src/lib.rs

@@ -24,3 +24,4 @@
 pub mod protocol;
 pub mod codec;
 pub mod relay;
+pub mod ds_hub;