fix: handle WebSocket disconnect properly and improve audio conversion

Author: hoangtung386

apps/gateway/src/routes/websocket.py

@@ -33,7 +33,11 @@ async def websocket_stream(
 
     try:
         while True:
-            data = await websocket.receive()
+            try:
+                data = await websocket.receive()
+            except RuntimeError:
+                # WebSocket already disconnected
+                break
 
             if "bytes" in data:
                 audio_data = data["bytes"]

apps/gateway/src/static/index.html

@@ -118,20 +118,42 @@ <h1>🎤 Voice Interaction</h1>
             }
         }
 
-        async function convertAndSend(audioBlob) {
-            // Convert webm to raw PCM using Web Audio API
-            const arrayBuffer = await audioBlob.arrayBuffer();
-            const audioContext = new AudioContext();
-            const audioBuffer = await audioContext.decodeAudioData(arrayBuffer);
-            
-            // Convert to mono 16kHz
-            const channelData = audioBuffer.getChannelData(0);
-            const samples = channelData.filter((_, i) => i % 3 === 0); // Downsample
-            const int16Array = new Int16Array(samples.length);
-            
-            for (let i = 0; i < samples.length; i++) {
-                int16Array[i] = Math.max(-1, Math.min(1, samples[i])) * 32767;
+async function convertAndSend(audioBlob) {
+            try {
+                const arrayBuffer = await audioBlob.arrayBuffer();
+                const audioContext = new AudioContext();
+                const audioBuffer = await audioContext.decodeAudioData(arrayBuffer);
+                
+                // Get mono channel and convert to 16kHz
+                const channelData = audioBuffer.getChannelData(0);
+                const sampleRate = audioBuffer.sampleRate;
+                const targetSampleRate = 16000;
+                
+                // Resample
+                const ratio = sampleRate / targetSampleRate;
+                const newLength = Math.floor(channelData.length / ratio);
+                const resampled = new Float32Array(newLength);
+                
+                for (let i = 0; i < newLength; i++) {
+                    resampled[i] = channelData[Math.floor(i * ratio)];
+                }
+                
+                // Convert to Int16 PCM
+                const int16Array = new Int16Array(newLength);
+                for (let i = 0; i < newLength; i++) {
+                    const sample = Math.max(-1, Math.min(1, resampled[i]));
+                    int16Array[i] = sample * 32767;
+                }
+                
+                if (ws && ws.readyState === WebSocket.OPEN) {
+                    ws.send(int16Array.buffer);
+                }
+                
+                await audioContext.close();
+            } catch (e) {
+                console.error('Audio conversion error:', e);
             }
+        }
 
             if (ws && ws.readyState === WebSocket.OPEN) {
                 ws.send(int16Array.buffer);