WebSocket Messages

{
  "type": "session_init",
  "session_id": "550e8400-e29b-41d4-a716-446655440000"
}

{
  "type": "transcription",
  "text": "[SPEAKER_0 | 0.000 --> 3.450]: Hello, how are you doing today?",
  "timestamp": 1703123456.789,
  "audio_file": "audio_chunks/550e8400-e29b-41d4-a716-446655440000_20231221_143056_123456.wav"
}

{
  "type": "warning",
  "message": "Audio chunk dropped - processing backlog."
}

// Send audio buffer as binary data
const audioBuffer = new ArrayBuffer(1024 * 2); // 1024 samples * 2 bytes per sample
const audioView = new Int16Array(audioBuffer);

// Fill with audio data from microphone or file
navigator.mediaDevices.getUserMedia({ audio: true })
  .then(stream => {
    const audioContext = new AudioContext();
    const source = audioContext.createMediaStreamSource(stream);
    const processor = audioContext.createScriptProcessor(1024, 1, 1);
    
    processor.onaudioprocess = function(e) {
      const inputBuffer = e.inputBuffer;
      const inputData = inputBuffer.getChannelData(0);
      
      // Convert float32 to int16
      const int16Buffer = new Int16Array(inputData.length);
      for (let i = 0; i < inputData.length; i++) {
        int16Buffer[i] = Math.max(-32768, Math.min(32767, inputData[i] * 32767));
      }
      
      // Send as binary data
      if (ws.readyState === WebSocket.OPEN) {
        ws.send(int16Buffer.buffer);
      }
    };
    
    source.connect(processor);
    processor.connect(audioContext.destination);
  });

class TranscriptionClient {
  constructor(url) {
    this.url = url;
    this.ws = null;
    this.sessionId = null;
    this.reconnectInterval = 5000;
  }
  
  connect() {
    this.ws = new WebSocket(this.url);
    
    this.ws.onopen = () => {
      console.log('Connected to transcription service');
    };
    
    this.ws.onmessage = (event) => {
      const data = JSON.parse(event.data);
      this.handleMessage(data);
    };
    
    this.ws.onclose = () => {
      console.log('Connection closed, attempting reconnect...');
      setTimeout(() => this.connect(), this.reconnectInterval);
    };
    
    this.ws.onerror = (error) => {
      console.error('WebSocket error:', error);
    };
  }
  
  handleMessage(data) {
    switch(data.type) {
      case 'session_init':
        this.sessionId = data.session_id;
        console.log('Session initialized:', this.sessionId);
        this.onSessionInit(data);
        break;
        
      case 'transcription':
        console.log('Transcription:', data.text);
        this.onTranscription(data);
        break;
        
      case 'warning':
        console.warn('Warning:', data.message);
        this.onWarning(data);
        break;
        
      default:
        console.log('Unknown message type:', data.type);
    }
  }
  
  sendAudio(audioBuffer) {
    if (this.ws && this.ws.readyState === WebSocket.OPEN) {
      this.ws.send(audioBuffer);
    }
  }
  
  // Override these methods in your implementation
  onSessionInit(data) {}
  onTranscription(data) {}
  onWarning(data) {}
}

// Usage
const client = new TranscriptionClient('ws://localhost:8000/ws/transcribe');
client.connect();

// Override handlers
client.onTranscription = (data) => {
  // Parse speaker information
  const match = data.text.match(/\[(\w+) \| ([\d.]+) --> ([\d.]+)\]: (.+)/);
  if (match) {
    const [, speaker, startTime, endTime, text] = match;
    console.log(`${speaker} (${startTime}-${endTime}s): ${text}`);
  }
};