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'use strict';
const util = require('node:util');
const Bonjour = require('bonjour-service').Bonjour;
const CastClient = require('castv2-client').Client;
const DefaultMediaReceiver = require('castv2-client').DefaultMediaReceiver;
/**
* Progress logging, off unless asked for:
*
* NODE_DEBUG=cast-chromecast npm start
*
* The receiver reports its state on a timer, so `player status: PLAYING`
* repeats for as long as a film runs and buries everything else in the
* terminal. Node's own `debuglog` is used rather than a flag of our own: it
* costs nothing when disabled — the message is never even formatted — and it
* is the knob a Node developer already expects to reach for.
*
* Failures do not come through here. A connection that dies silently is a
* connection nobody can diagnose, so those stay on `console.error`.
*/
const debug = util.debuglog('cast-chromecast');
const SCAN_DURATION_MS = 6000;
// The one track the receiver is ever told about. A side-loaded track cannot
// have its cues replaced in place, so changing subtitles means loading again
// with a new URL under this same id rather than adding a second track.
const TEXT_TRACK_ID = 1;
// White on nothing is unreadable over a bright scene, and the receiver's
// default style is exactly that. An outline costs no bandwidth.
const TEXT_TRACK_STYLE = Object.freeze({
backgroundColor: '#00000000',
foregroundColor: '#FFFFFFFF',
edgeType: 'OUTLINE',
edgeColor: '#000000FF',
fontScale: 1.0,
fontFamily: 'SANS_SERIF',
});
/**
* What to hand `player.load()` for a stream, with or without subtitles.
*
* `streamType: 'LIVE'` because the relay has no beginning to seek back to —
* the film's own timeline lives on this side, and a seek restarts the relay.
*/
function mediaFor(mediaUrl, subtitle) {
const media = {
contentId: mediaUrl,
contentType: 'video/mp4',
streamType: 'LIVE',
};
if (subtitle && subtitle.url) {
media.tracks = [{
trackId: TEXT_TRACK_ID,
type: 'TEXT',
trackContentId: subtitle.url,
trackContentType: 'text/vtt',
subtype: 'SUBTITLES',
name: subtitle.label || 'Subtitles',
language: subtitle.language || 'und',
}];
media.textTrackStyle = TEXT_TRACK_STYLE;
}
return media;
}
function loadOptionsFor(subtitle) {
return {
autoplay: true,
activeTrackIds: subtitle && subtitle.url ? [TEXT_TRACK_ID] : [],
};
}
class CastChromecast {
constructor() {
this._bonjour = null;
this._browser = null;
this._devices = new Map();
this._client = null;
this._player = null;
this._connectedDevice = null;
}
async discover() {
this._devices.clear();
if (this._browser) {
this._browser.stop();
this._browser = null;
}
if (!this._bonjour) {
this._bonjour = new Bonjour();
}
debug('[cast-chromecast] scanning for devices...');
return new Promise((resolve) => {
this._browser = this._bonjour.find({ type: 'googlecast' }, (service) => {
const id = service.txt?.id || service.name;
const name = service.txt?.fn || service.name;
const host = service.addresses?.find((a) => /^\d+\.\d+\.\d+\.\d+$/.test(a))
|| (service.referer && service.referer.address);
const port = service.port || 8009;
if (host && id) {
this._devices.set(id, { id, name, host, port });
debug(`[cast-chromecast] discovered: "${name}" at ${host}:${port}`);
}
});
setTimeout(() => {
if (this._browser) {
this._browser.stop();
this._browser = null;
}
const devices = Array.from(this._devices.values());
debug(`[cast-chromecast] scan complete: ${devices.length} device(s)`);
resolve(devices);
}, SCAN_DURATION_MS);
});
}
async connect(deviceId, mediaUrl, subtitle) {
const device = this._devices.get(deviceId);
if (!device) throw new Error(`Unknown device: ${deviceId}`);
await this.disconnect();
debug(`[cast-chromecast] connecting to "${device.name}" (${device.host}:${device.port})`);
const client = new CastClient();
await new Promise((resolve, reject) => {
client.on('error', (err) => {
// Not `debug`: this fires when the socket to the receiver dies, and it
// is the only trace of why the cast stopped.
console.error(`[cast-chromecast] client error: ${err.message}`);
this._cleanup();
});
client.connect(device.host, () => resolve());
setTimeout(() => reject(new Error('Connection timeout')), 10000);
});
this._client = client;
this._connectedDevice = device;
const player = await new Promise((resolve, reject) => {
client.launch(DefaultMediaReceiver, (err, p) => {
if (err) return reject(err);
resolve(p);
});
});
this._player = player;
player.on('status', (status) => {
debug(`[cast-chromecast] player status: ${status.playerState}`);
});
debug(`[cast-chromecast] loading with ${subtitle?.url ? 'subtitles' : 'no subtitles'}`);
const status = await new Promise((resolve, reject) => {
player.load(mediaFor(mediaUrl, subtitle), loadOptionsFor(subtitle),
(err, s) => {
if (err) return reject(err);
resolve(s);
});
});
debug(`[cast-chromecast] loaded on "${device.name}", state: ${status.playerState}`);
return { deviceName: device.name, playerState: status.playerState };
}
async reload(mediaUrl, subtitle) {
if (!this._player) throw new Error('Not connected');
debug(`[cast-chromecast] reloading stream on "${this._connectedDevice?.name}"`
+ ` with ${subtitle?.url ? 'subtitles' : 'no subtitles'}`);
const status = await new Promise((resolve, reject) => {
this._player.load(mediaFor(mediaUrl, subtitle), loadOptionsFor(subtitle),
(err, s) => {
if (err) return reject(err);
resolve(s);
});
});
debug(`[cast-chromecast] reloaded, state: ${status.playerState}`);
return { playerState: status.playerState };
}
async disconnect() {
if (this._player) {
try {
await new Promise((resolve) => {
this._player.stop(() => resolve());
});
} catch { /* already stopped */ }
}
this._cleanup();
}
getStatus() {
return {
connected: this._client !== null,
deviceName: this._connectedDevice?.name || null,
};
}
_cleanup() {
if (this._client) {
try { this._client.close(); } catch { /* ignore */ }
}
this._client = null;
this._player = null;
this._connectedDevice = null;
}
}
module.exports = CastChromecast;
module.exports.mediaFor = mediaFor;
module.exports.loadOptionsFor = loadOptionsFor;
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