refactor: Migrate screen sharing media handling from direct WebRTC to Mediasoup.

This commit is contained in:
2026-02-23 16:48:05 +01:00
parent ff013b206a
commit 0f250d5c2a
19 changed files with 1925 additions and 574 deletions

View File

@@ -2,137 +2,196 @@ const socket = io();
const remoteVideo = document.getElementById('remoteVideo');
const overlay = document.getElementById('overlay');
let peerConnection;
let broadcasterPeerId = null; // Track who the broadcaster is
let device;
let recvTransport;
let consumers = {}; // consumerId -> consumer
// Fetch TURN credentials dynamically from the server
const turnHost = window.location.hostname;
let config = {
iceServers: [
{ urls: `stun:${turnHost}:3478` }
],
iceCandidatePoolSize: 5
};
async function init() {
try {
// 1. Get router RTP capabilities
const rtpCapabilities = await new Promise((resolve, reject) => {
socket.emit('getRouterRtpCapabilities', (data) => {
if (data.error) reject(new Error(data.error));
else resolve(data);
});
});
// Load TURN credentials before any connections
fetch('/turn-config')
.then(r => r.json())
.then(turn => {
config = {
iceServers: [
{ urls: `stun:${turnHost}:3478` },
{ urls: `turn:${turnHost}:3478`, username: turn.username, credential: turn.credential }
],
iceCandidatePoolSize: 5
};
})
.catch(e => console.error('Failed to load TURN config:', e));
// 2. Create mediasoup Device and load capabilities
device = new mediasoupClient.Device();
await device.load({ routerRtpCapabilities: rtpCapabilities });
socket.on('offer', (id, description) => {
// Track the broadcaster's socket ID so we only react to THEIR disconnect
broadcasterPeerId = id;
// Close any existing connection before creating a new one
if (peerConnection) {
peerConnection.close();
peerConnection = null;
// 3. Create recv transport
const transportParams = await new Promise((resolve, reject) => {
socket.emit('createWebRtcTransport', { direction: 'recv' }, (data) => {
if (data.error) reject(new Error(data.error));
else resolve(data);
});
});
recvTransport = device.createRecvTransport(transportParams);
// Transport 'connect' event: DTLS handshake
recvTransport.on('connect', async ({ dtlsParameters }, callback, errback) => {
try {
await new Promise((resolve, reject) => {
socket.emit('connectTransport', {
transportId: recvTransport.id,
dtlsParameters
}, (result) => {
if (result && result.error) reject(new Error(result.error));
else resolve();
});
});
callback();
} catch (e) {
errback(e);
}
});
// 4. Get existing producers and consume them
const existingProducers = await new Promise((resolve, reject) => {
socket.emit('getProducers', (data) => {
if (data.error) reject(new Error(data.error));
else resolve(data);
});
});
for (const { producerId, kind } of existingProducers) {
await consumeProducer(producerId, kind);
}
} catch (e) {
console.error('Failed to initialize mediasoup viewer:', e);
}
peerConnection = new RTCPeerConnection(config);
peerConnection.ontrack = event => {
remoteVideo.srcObject = event.streams[0];
}
async function consumeProducer(producerId, kind) {
try {
const result = await new Promise((resolve, reject) => {
socket.emit('consume', {
transportId: recvTransport.id,
producerId,
rtpCapabilities: device.rtpCapabilities
}, (data) => {
if (data.error) reject(new Error(data.error));
else resolve(data);
});
});
const consumer = await recvTransport.consume({
id: result.id,
producerId: result.producerId,
kind: result.kind,
rtpParameters: result.rtpParameters
});
consumers[consumer.id] = consumer;
// Attach track to the video element
const { track } = consumer;
if (!remoteVideo.srcObject) {
remoteVideo.srcObject = new MediaStream();
}
remoteVideo.srcObject.addTrack(track);
remoteVideo.classList.add('active');
overlay.classList.add('hidden');
};
// Auto-unmute when the user interacts with the document to bypass browser autoplay restrictions
document.addEventListener('click', () => {
remoteVideo.muted = false;
remoteVideo.volume = 1.0;
}, {once: true});
// Monitor ICE connection state for stability
peerConnection.oniceconnectionstatechange = () => {
console.log('ICE state:', peerConnection.iceConnectionState);
if (peerConnection.iceConnectionState === 'failed') {
console.log('ICE failed, attempting restart...');
peerConnection.restartIce();
} else if (peerConnection.iceConnectionState === 'disconnected') {
setTimeout(() => {
if (peerConnection && peerConnection.iceConnectionState === 'disconnected') {
console.log('ICE still disconnected, attempting restart...');
peerConnection.restartIce();
}
}, 3000);
}
};
peerConnection.onicecandidate = event => {
if (event.candidate) {
socket.emit('candidate', id, event.candidate);
}
};
peerConnection
.setRemoteDescription(description)
.then(() => peerConnection.createAnswer())
.then(sdp => {
let sdpLines = sdp.sdp.split('\r\n');
let opusPayloadType = null;
for (let i = 0; i < sdpLines.length; i++) {
if (sdpLines[i].includes('a=rtpmap:') && sdpLines[i].includes('opus/48000/2')) {
const match = sdpLines[i].match(/a=rtpmap:(\d+) /);
if (match) opusPayloadType = match[1];
}
}
if (opusPayloadType) {
let fmtpFound = false;
for (let i = 0; i < sdpLines.length; i++) {
if (sdpLines[i].startsWith(`a=fmtp:${opusPayloadType}`)) {
sdpLines[i] = `a=fmtp:${opusPayloadType} minptime=10;useinbandfec=1;maxplaybackrate=48000;stereo=1;sprop-stereo=1;maxaveragebitrate=510000;cbr=1`;
fmtpFound = true;
}
}
if (!fmtpFound) {
sdpLines.push(`a=fmtp:${opusPayloadType} minptime=10;useinbandfec=1;maxplaybackrate=48000;stereo=1;sprop-stereo=1;maxaveragebitrate=510000;cbr=1`);
}
}
sdp.sdp = sdpLines.join('\r\n');
return peerConnection.setLocalDescription(sdp);
})
.then(() => {
socket.emit('answer', id, peerConnection.localDescription);
// Resume the consumer (server starts them paused)
await new Promise((resolve, reject) => {
socket.emit('resumeConsumer', { consumerId: consumer.id }, (result) => {
if (result && result.error) reject(new Error(result.error));
else resolve();
});
});
});
socket.on('candidate', (id, candidate) => {
if (peerConnection) {
peerConnection.addIceCandidate(new RTCIceCandidate(candidate))
.catch(e => console.error(e));
consumer.on('trackended', () => {
console.log(`Track ended for consumer ${consumer.id}`);
});
consumer.on('transportclose', () => {
console.log(`Transport closed for consumer ${consumer.id}`);
});
} catch (e) {
console.error('Failed to consume producer:', e);
}
}
// Listen for new producers (e.g. broadcaster adds audio after starting)
socket.on('newProducer', async ({ producerId, kind }) => {
if (recvTransport) {
await consumeProducer(producerId, kind);
}
});
socket.on('broadcaster', () => {
socket.emit('viewer');
// Handle producer closed (broadcaster stopped a track)
socket.on('producerClosed', ({ consumerId }) => {
const consumer = consumers[consumerId];
if (consumer) {
// Remove the track from the video element
if (remoteVideo.srcObject) {
const track = consumer.track;
if (track) {
remoteVideo.srcObject.removeTrack(track);
}
}
consumer.close();
delete consumers[consumerId];
}
// If no more consumers, show overlay
if (Object.keys(consumers).length === 0) {
remoteVideo.classList.remove('active');
remoteVideo.srcObject = null;
overlay.classList.remove('hidden');
}
});
// CRITICAL: Only react to the BROADCASTER's disconnect, not other viewers
socket.on('disconnectPeer', (id) => {
if (id !== broadcasterPeerId) return; // Ignore other viewers disconnecting
if (peerConnection) {
peerConnection.close();
peerConnection = null;
// Broadcaster connected - try to initialize
socket.on('broadcasterConnected', () => {
// Re-init to pick up new producers
if (!device) {
init();
} else {
// Just fetch new producers
socket.emit('getProducers', async (producers) => {
for (const { producerId, kind } of producers) {
// Check if we're already consuming this producer
const alreadyConsuming = Object.values(consumers).some(c => c.producerId === producerId);
if (!alreadyConsuming) {
await consumeProducer(producerId, kind);
}
}
});
}
broadcasterPeerId = null;
});
// Broadcaster disconnected
socket.on('broadcasterDisconnected', () => {
// Close all consumers
Object.values(consumers).forEach(consumer => {
consumer.close();
});
consumers = {};
remoteVideo.classList.remove('active');
remoteVideo.srcObject = null;
overlay.classList.remove('hidden');
overlay.querySelector('h1').innerText = 'Stream Ended';
overlay.querySelector('.status-indicator span:last-child').innerText = 'Waiting for new stream...';
});
// Auto-unmute when the user interacts with the document
document.addEventListener('click', () => {
remoteVideo.muted = false;
remoteVideo.volume = 1.0;
}, { once: true });
// Initialize on connect
socket.on('connect', () => {
socket.emit('viewer');
init();
});