feat: Dynamically fetch TURN credentials, improve WebRTC connection stability with ICE restart logic, and configure TURN via environment variables.

public/viewer.js

@@ -3,17 +3,30 @@ const remoteVideo = document.getElementById('remoteVideo');
 const overlay = document.getElementById('overlay');
 
 let peerConnection;
-const config = {
+
+// Fetch TURN credentials dynamically from the server
+const turnHost = window.location.hostname;
+let config = {
     iceServers: [
-        { urls: "stun:localhost:3478" },
-        {
-            urls: "turn:localhost:3478",
-            username: "myuser",
-            credential: "mypassword"
-        }
-    ]
+        { urls: `stun:${turnHost}:3478` }
+    ],
+    iceCandidatePoolSize: 5
 };
 
+// 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));
+
 socket.on('offer', (id, description) => {
     // Close any existing connection before creating a new one
     if (peerConnection) {
@@ -31,10 +44,27 @@ socket.on('offer', (id, description) => {
     // Auto-unmute when the user interacts with the document to bypass browser autoplay restrictions
     document.addEventListener('click', () => {
         remoteVideo.muted = false;
-        // Set sink to max possible volume explicitly avoiding browser gain staging
         remoteVideo.volume = 1.0; 
     }, {once: true});
 
+    // Monitor ICE connection state for stability
+    peerConnection.oniceconnectionstatechange = () => {
+        console.log('ICE state:', peerConnection.iceConnectionState);
+        if (peerConnection.iceConnectionState === 'failed') {
+            // Try ICE restart before giving up
+            console.log('ICE failed, attempting restart...');
+            peerConnection.restartIce();
+        } else if (peerConnection.iceConnectionState === 'disconnected') {
+            // Wait briefly then check if it recovered
+            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);