gemini-multimodal-live-dev-guide/part_2_dev_api/chapter_04/index.html at main · ffesseler/gemini-multimodal-live-dev-guide · GitHub

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<!DOCTYPE html>
<!--
 Copyright 2024 Google LLC

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at

     http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
-->

<html>
<head>
  <title>Gemini Text-to-Speech WebSocket Test</title>
  <style>
    .header-section {
      padding: 20px;
      margin-bottom: 30px;
      background-color: #f5f5f5;
      border-bottom: 1px solid #ddd;
    }
    .header-section h1 {
      margin-top: 0;
      color: #333;
    }
    .header-section p {
      margin-bottom: 0;
      color: #666;
    }
    .input-container {
      margin: 20px;
      display: flex;
      gap: 10px;
    }
    #userInput {
      padding: 8px;
      width: 300px;
    }
    #sendButton {
      padding: 8px 16px;
      cursor: pointer;
    }
    #output {
      margin: 20px;
    }
  </style>
</head>
<body>
  <div class="header-section">
    <h1>Gemini Text-to-Speech with WebSockets</h1>
    <p>This application demonstrates real-time text-to-speech using the Gemini API. Type a message and receive an audio response that plays automatically in your browser. The app uses WebSockets for communication and AudioContext for handling audio playback.</p>
  </div>

  <div class="input-container">
    <input type="text" id="userInput" placeholder="Type your message...">
    <button id="sendButton" onclick="sendUserMessage()">Send</button>
  </div>
  <div id="output"></div>

  <script>
    const output = document.getElementById('output');
    const apiKey = '<YOUR_API_KEY>';
    let audioContext;
    let initialized = false;
    let audioQueue = [];
    let isPlayingAudio = false;

    // Initialize audio when sending the first message
    async function ensureAudioInitialized() {
      if (!initialized) {
        audioContext = new (window.AudioContext || window.webkitAudioContext)({ sampleRate: 24000 });
        await audioContext.resume();
        initialized = true;
        console.log('Audio context initialized:', audioContext.state);
      }
    }

    async function playAudioChunk(base64AudioChunk) {
      try {
        await ensureAudioInitialized();

        // Add to queue and process if not already playing
        audioQueue.push(base64AudioChunk);
        if (!isPlayingAudio) {
          await processAudioQueue();
        }
      } catch (error) {
        console.error('Error queuing audio chunk:', error);
      }
    }

    async function processAudioQueue() {
      if (audioQueue.length === 0 || isPlayingAudio) {
        return;
      }

      isPlayingAudio = true;

      try {
        while (audioQueue.length > 0) {
          const chunk = audioQueue.shift();

          if (audioContext.state === 'suspended') {
            await audioContext.resume();
          }

          const arrayBuffer = base64ToArrayBuffer(chunk);
          const float32Data = convertPCM16LEToFloat32(arrayBuffer);

          const audioBuffer = audioContext.createBuffer(1, float32Data.length, 24000);
          audioBuffer.getChannelData(0).set(float32Data);

          const source = audioContext.createBufferSource();
          source.buffer = audioBuffer;
          source.connect(audioContext.destination);

          // Wait for the current chunk to finish before playing the next
          await new Promise((resolve) => {
            source.onended = resolve;
            source.start(0);
          });

          console.log('Finished playing chunk, remaining chunks:', audioQueue.length);
        }
      } catch (error) {
        console.error('Error processing audio queue:', error);
      } finally {
        isPlayingAudio = false;
      }
    }

    const host = 'generativelanguage.googleapis.com';
    const endpoint = `wss://${host}/ws/google.ai.generativelanguage.v1alpha.GenerativeService.BidiGenerateContent?key=${apiKey}`;

    const ws = new WebSocket(endpoint);
    let audioChunks = []; // Array to collect audio chunks
    let isReceivingResponse = false; // Flag to track if we're receiving a response

    const userInput = document.getElementById('userInput');
    const sendButton = document.getElementById('sendButton');

    function sendUserMessage() {
      if (!userInput.value.trim()) {
        return;
      }

      const message = userInput.value;
      logMessage('You: ' + message);

      const contentMessage = {
        client_content: {
          turns: [{
            role: "user",
            parts: [{ text: message }]
          }],
          turn_complete: true
        }
      };

      console.log('Sending content message:', contentMessage);
      ws.send(JSON.stringify(contentMessage));

      // Clear input after sending
      userInput.value = '';
    }

    // Add enter key support
    userInput.addEventListener('keypress', (e) => {
      if (e.key === 'Enter') {
        sendUserMessage();
      }
    });

    // Disable input until connection is ready
    userInput.disabled = true;
    sendButton.disabled = true;

    ws.onopen = () => {
      console.log('WebSocket connection is opening...');
      logMessage('Connected to Gemini');

      const setupMessage = {
        setup: {
          model: "models/gemini-2.0-flash-exp",
          generation_config: {
            response_modalities: ["audio"]
          }
        }
      };

      console.log('Sending setup message:', setupMessage);
      ws.send(JSON.stringify(setupMessage));
    };

    ws.onmessage = async (event) => {
      try {
        console.log('Event:', event);

        let wsResponse;
        if (event.data instanceof Blob) {
          const responseText = await event.data.text();
          wsResponse = JSON.parse(responseText);
        } else {
          wsResponse = JSON.parse(event.data);
        }

        console.log('WebSocket Response:', wsResponse);

        if (wsResponse.setupComplete) {
          // Enable input after setup is complete
          userInput.disabled = false;
          sendButton.disabled = false;
        }
        else if (wsResponse.serverContent?.modelTurn?.parts?.[0]?.inlineData) {
          try {
            const audioData = wsResponse.serverContent.modelTurn.parts[0].inlineData.data;

            // Only show "Speaking..." message when starting a new response
            if (!isPlayingAudio && audioQueue.length === 0) {
              logMessage('Gemini: Speaking...');
            }

            await playAudioChunk(audioData);

            // Show "Finished speaking" when the response is complete
            if (wsResponse.serverContent?.turnComplete) {
              logMessage('Gemini: Finished speaking');
            }
          } catch (error) {
            console.error('Error handling audio data:', error);
            console.log('Full response:', wsResponse);
          }
        }
      } catch (error) {
        console.error('Error parsing response:', error);
        console.log('Raw event data:', event.data);
        logMessage('Error parsing response: ' + error.message);
      }
    };

    function base64ToArrayBuffer(base64) {
      const binaryString = window.atob(base64);
      const bytes = new Uint8Array(binaryString.length);
      for (let i = 0; i < binaryString.length; i++) {
        bytes[i] = binaryString.charCodeAt(i);
      }
      return bytes.buffer;
    }

    function convertPCM16LEToFloat32(pcmData) {
      const inputArray = new Int16Array(pcmData);
      const float32Array = new Float32Array(inputArray.length);

      for (let i = 0; i < inputArray.length; i++) {
        float32Array[i] = inputArray[i] / 32768;
      }

      return float32Array;
    }

    ws.onerror = (error) => {
      console.error('WebSocket Error:', error);
      logMessage('WebSocket Error: ' + error.message);
    };

    ws.onclose = (event) => {
      console.log('Connection closed:', event);
      logMessage(`Connection closed - Code: ${event.code}, Reason: ${event.reason}`);
    };

    function logMessage(message) {
      const messageElement = document.createElement('p');
      messageElement.textContent = message;
      output.appendChild(messageElement);
    }

    // Rename to CustomResponse to avoid confusion with the built-in Response class
    class CustomResponse {
      constructor(data) {
        this.data = "";
        this.endOfTurn = false;

        if (data?.serverContent?.turnComplete) {
          this.endOfTurn = true;
        }

        if (data?.serverContent?.modelTurn?.parts?.[0]?.text) {
          this.data = data.serverContent.modelTurn.parts[0].text;
        }

        if (data?.serverContent?.modelTurn?.parts?.[0]?.inlineData) {
          this.data = data.serverContent.modelTurn.parts[0].inlineData.data;
        }
      }
    }
  </script>
</body>
</html>