SSML and LaTeX

using System.Net.WebSockets;
using System.Text;
using System.Text.Json;

// See SSML support requirements in the note above
class Program {
  // If you have not configured an environment variable, replace the following line with: private static readonly string ApiKey = "sk-xxx"
  private static readonly string ApiKey = Environment.GetEnvironmentVariable("DASHSCOPE_API_KEY") ?? throw new InvalidOperationException("DASHSCOPE_API_KEY environment variable is not set.");

  private const string WebSocketUrl = "wss://maas.qwencloudapi.com/api-ws/v1/inference/";
  // Output file path
  private const string OutputFilePath = "output.mp3";

  // WebSocket client
  private static ClientWebSocket _webSocket = new ClientWebSocket();
  // Cancellation token source
  private static CancellationTokenSource _cancellationTokenSource = new CancellationTokenSource();
  // Task ID
  private static string? _taskId;
  // Whether the task has started
  private static TaskCompletionSource<bool> _taskStartedTcs = new TaskCompletionSource<bool>();

  static async Task Main(string[] args) {
    try {
      // Clear the output file
      ClearOutputFile(OutputFilePath);

      // Connect to WebSocket service
      await ConnectToWebSocketAsync(WebSocketUrl);

      // Start the task to receive messages
      Task receiveTask = ReceiveMessagesAsync();

      // Send run-task command
      _taskId = GenerateTaskId();
      await SendRunTaskCommandAsync(_taskId);

      // Wait for the task-started event
      await _taskStartedTcs.Task;

      // Send the continue-task command. When using the SSML feature, this command can be sent only once.
      // Special characters need to be escaped.
      await SendContinueTaskCommandAsync("<speak rate=\"2\">My speaking rate is faster than a normal person's.</speak>");

      // Send the finish-task command
      await SendFinishTaskCommandAsync(_taskId);

      // Wait for the receive task to complete
      await receiveTask;

      Console.WriteLine("Task completed, connection closed.");
    } catch (OperationCanceledException) {
      Console.WriteLine("The task was canceled.");
    } catch (Exception ex) {
      Console.WriteLine($"An error occurred: {ex.Message}");
    } finally {
      _cancellationTokenSource.Cancel();
      _webSocket.Dispose();
    }
  }

  private static void ClearOutputFile(string filePath) {
    if (File.Exists(filePath)) {
      File.WriteAllText(filePath, string.Empty);
      Console.WriteLine("The output file has been cleared.");
    } else {
      Console.WriteLine("The output file does not exist and does not need to be cleared.");
    }
  }

  private static async Task ConnectToWebSocketAsync(string url) {
    var uri = new Uri(url);
    if (_webSocket.State == WebSocketState.Connecting || _webSocket.State == WebSocketState.Open) {
      return;
    }

    // Set headers for the WebSocket connection
    _webSocket.Options.SetRequestHeader("Authorization", $"bearer {ApiKey}");
    _webSocket.Options.SetRequestHeader("X-DashScope-DataInspection", "enable");

    try {
      await _webSocket.ConnectAsync(uri, _cancellationTokenSource.Token);
      Console.WriteLine("Successfully connected to the WebSocket service.");
    } catch (OperationCanceledException) {
      Console.WriteLine("WebSocket connection was canceled.");
    } catch (Exception ex) {
      Console.WriteLine($"WebSocket connection failed: {ex.Message}");
      throw;
    }
  }

  private static async Task SendRunTaskCommandAsync(string taskId) {
    var command = CreateCommand("run-task", taskId, "duplex", new {
      task_group = "audio",
      task = "tts",
      function = "SpeechSynthesizer",
      model = "cosyvoice-v3-flash",
      parameters = new
      {
        text_type = "PlainText",
        voice = "longanyang",
        format = "mp3",
        sample_rate = 22050,
        volume = 50,
        rate = 1,
        pitch = 1,
        // With enable_ssml: true, send continue-task only once
        enable_ssml = true
      },
      input = new { }
    });

    await SendJsonMessageAsync(command);
    Console.WriteLine("Sent run-task command.");
  }

  private static async Task SendContinueTaskCommandAsync(string text) {
    if (_taskId == null) {
      throw new InvalidOperationException("Task ID is not initialized.");
    }

    var command = CreateCommand("continue-task", _taskId, "duplex", new {
      input = new {
        text
      }
    });

    await SendJsonMessageAsync(command);
    Console.WriteLine("Sent continue-task command.");
  }

  private static async Task SendFinishTaskCommandAsync(string taskId) {
    var command = CreateCommand("finish-task", taskId, "duplex", new {
      input = new { }
    });

    await SendJsonMessageAsync(command);
    Console.WriteLine("Sent finish-task command.");
  }

  private static async Task SendJsonMessageAsync(string message) {
    var buffer = Encoding.UTF8.GetBytes(message);
    try {
      await _webSocket.SendAsync(new ArraySegment<byte>(buffer), WebSocketMessageType.Text, true, _cancellationTokenSource.Token);
    } catch (OperationCanceledException) {
      Console.WriteLine("Message sending was canceled.");
    }
  }

  private static async Task ReceiveMessagesAsync() {
    while (_webSocket.State == WebSocketState.Open) {
      var response = await ReceiveMessageAsync();
      if (response != null) {
        var eventStr = response.RootElement.GetProperty("header").GetProperty("event").GetString();
        switch (eventStr) {
          case "task-started":
            Console.WriteLine("Task started.");
            _taskStartedTcs.TrySetResult(true);
            break;
          case "task-finished":
            Console.WriteLine("Task finished.");
            _cancellationTokenSource.Cancel();
            break;
          case "task-failed":
            Console.WriteLine("Task failed: " + response.RootElement.GetProperty("header").GetProperty("error_message").GetString());
            _cancellationTokenSource.Cancel();
            break;
          default:
            // result-generated can be handled here
            break;
        }
      }
    }
  }

  private static async Task<JsonDocument?> ReceiveMessageAsync() {
    var buffer = new byte[1024 * 4];
    var segment = new ArraySegment<byte>(buffer);

    try {
      WebSocketReceiveResult result = await _webSocket.ReceiveAsync(segment, _cancellationTokenSource.Token);

      if (result.MessageType == WebSocketMessageType.Close) {
        await _webSocket.CloseAsync(WebSocketCloseStatus.NormalClosure, "Closing", _cancellationTokenSource.Token);
        return null;
      }

      if (result.MessageType == WebSocketMessageType.Binary) {
        // Handle binary data
        Console.WriteLine("Receiving binary data...");

        // Save binary data to a file
        using (var fileStream = new FileStream(OutputFilePath, FileMode.Append)) {
          fileStream.Write(buffer, 0, result.Count);
        }

        return null;
      }

      string message = Encoding.UTF8.GetString(buffer, 0, result.Count);
      return JsonDocument.Parse(message);
    } catch (OperationCanceledException) {
      Console.WriteLine("Message reception was canceled.");
      return null;
    }
  }

  private static string GenerateTaskId() {
    return Guid.NewGuid().ToString("N").Substring(0, 32);
  }

  private static string CreateCommand(string action, string taskId, string streaming, object payload) {
    var command = new {
      header = new {
        action,
        task_id = taskId,
        streaming
      },
      payload
    };

    return JsonSerializer.Serialize(command);
  }
}

my-php-project/
├── composer.json
├── vendor/
└── index.php

{
  "require": {
    "react/event-loop": "^1.3",
    "react/socket": "^1.11",
    "react/stream": "^1.2",
    "react/http": "^1.1",
    "ratchet/pawl": "^0.4"
  },
  "autoload": {
    "psr-4": {
      "App\\": "src/"
    }
  }
}

<!-- See SSML support requirements in the note above -->

<?php

require __DIR__ . '/vendor/autoload.php';

use Ratchet\Client\Connector;
use React\EventLoop\Loop;
use React\Socket\Connector as SocketConnector;

// If you have not configured an environment variable, replace the following line with: $api_key = "sk-xxx"
$api_key = getenv("DASHSCOPE_API_KEY");
$websocket_url = 'wss://maas.qwencloudapi.com/api-ws/v1/inference/'; // WebSocket server address
$output_file = 'output.mp3'; // Output file path

$loop = Loop::get();

if (file_exists($output_file)) {
    // Clear the file content
    file_put_contents($output_file, '');
}

// Create a custom connector
$socketConnector = new SocketConnector($loop, [
    'tcp' => [
        'bindto' => '0.0.0.0:0',
    ],
    'tls' => [
        'verify_peer' => false,
        'verify_peer_name' => false,
    ],
]);

$connector = new Connector($loop, $socketConnector);

$headers = [
    'Authorization' => 'bearer ' . $api_key,
    'X-DashScope-DataInspection' => 'enable'
];

$connector($websocket_url, [], $headers)->then(function ($conn) use ($loop, $output_file) {
    echo "Connected to WebSocket server\n";

    // Generate task ID
    $taskId = generateTaskId();

    // Send run-task command
    sendRunTaskMessage($conn, $taskId);

    // Define the function to send the continue-task command
    $sendContinueTask = function() use ($conn, $loop, $taskId) {
        // Send the continue-task command. When using the SSML feature, this command can be sent only once.
        $continueTaskMessage = json_encode([
            "header" => [
                "action" => "continue-task",
                "task_id" => $taskId,
                "streaming" => "duplex"
            ],
            "payload" => [
                "input" => [
                    // Special characters need to be escaped
                    "text" => "<speak rate=\"2\">My speaking rate is faster than a normal person's.</speak>"
                ]
            ]
        ]);
        $conn->send($continueTaskMessage);

        // Send the finish-task command
        sendFinishTaskMessage($conn, $taskId);
    };

    // Flag to check if the task-started event is received
    $taskStarted = false;

    // Listen for messages
    $conn->on('message', function($msg) use ($conn, $sendContinueTask, $loop, &$taskStarted, $taskId, $output_file) {
        if ($msg->isBinary()) {
            // Write binary data to the local file
            file_put_contents($output_file, $msg->getPayload(), FILE_APPEND);
        } else {
            // Handle non-binary messages
            $response = json_decode($msg, true);

            if (isset($response['header']['event'])) {
                handleEvent($conn, $response, $sendContinueTask, $loop, $taskId, $taskStarted);
            } else {
                echo "Unknown message format\n";
            }
        }
    });

    // Listen for connection close
    $conn->on('close', function($code = null, $reason = null) {
        echo "Connection closed\n";
        if ($code !== null) {
            echo "Close code: " . $code . "\n";
        }
        if ($reason !== null) {
            echo "Close reason: " . $reason . "\n";
        }
    });
}, function ($e) {
    echo "Could not connect: {$e->getMessage()}\n";
});

$loop->run();

/**
 * Generate task ID
 * @return string
 */
function generateTaskId(): string {
    return bin2hex(random_bytes(16));
}

/**
 * Send run-task command
 * @param $conn
 * @param $taskId
 */
function sendRunTaskMessage($conn, $taskId) {
    $runTaskMessage = json_encode([
        "header" => [
            "action" => "run-task",
            "task_id" => $taskId,
            "streaming" => "duplex"
        ],
        "payload" => [
            "task_group" => "audio",
            "task" => "tts",
            "function" => "SpeechSynthesizer",
            "model" => "cosyvoice-v3-flash",
            "parameters" => [
                "text_type" => "PlainText",
                "voice" => "longanyang",
                "format" => "mp3",
                "sample_rate" => 22050,
                "volume" => 50,
                "rate" => 1,
                "pitch" => 1,
                // With enable_ssml: true, send continue-task only once
                "enable_ssml" => true
            ],
            "input" => (object) []
        ]
    ]);
    echo "Preparing to send run-task command: " . $runTaskMessage . "\n";
    $conn->send($runTaskMessage);
    echo "run-task command sent\n";
}

/**
 * Read audio file
 * @param string $filePath
 * @return bool|string
 */
function readAudioFile(string $filePath) {
    $voiceData = file_get_contents($filePath);
    if ($voiceData === false) {
        echo "Failed to read audio file\n";
    }
    return $voiceData;
}

/**
 * Split audio data
 * @param string $data
 * @param int $chunkSize
 * @return array
 */
function splitAudioData(string $data, int $chunkSize): array {
    return str_split($data, $chunkSize);
}

/**
 * Send finish-task command
 * @param $conn
 * @param $taskId
 */
function sendFinishTaskMessage($conn, $taskId) {
    $finishTaskMessage = json_encode([
        "header" => [
            "action" => "finish-task",
            "task_id" => $taskId,
            "streaming" => "duplex"
        ],
        "payload" => [
            "input" => (object) []
        ]
    ]);
    echo "Preparing to send finish-task command: " . $finishTaskMessage . "\n";
    $conn->send($finishTaskMessage);
    echo "finish-task command sent\n";
}

/**
 * Handle events
 * @param $conn
 * @param $response
 * @param $sendContinueTask
 * @param $loop
 * @param $taskId
 * @param $taskStarted
 */
function handleEvent($conn, $response, $sendContinueTask, $loop, $taskId, &$taskStarted) {
    switch ($response['header']['event']) {
        case 'task-started':
            echo "Task started, sending continue-task command...\n";
            $taskStarted = true;
            // Send continue-task command
            $sendContinueTask();
            break;
        case 'result-generated':
            // Ignore result-generated event
            break;
        case 'task-finished':
            echo "Task finished\n";
            $conn->close();
            break;
        case 'task-failed':
            echo "Task failed\n";
            echo "Error code: " . $response['header']['error_code'] . "\n";
            echo "Error message: " . $response['header']['error_message'] . "\n";
            $conn->close();
            break;
        case 'error':
            echo "Error: " . $response['payload']['message'] . "\n";
            break;
        default:
            echo "Unknown event: " . $response['header']['event'] . "\n";
            break;
    }

    // If the task is finished, close the connection
    if ($response['header']['event'] == 'task-finished') {
        // Wait for 1 second to ensure all data is transferred
        $loop->addTimer(1, function() use ($conn) {
            $conn->close();
            echo "Client closes connection\n";
        });
    }

    // If task-started event is not received, close the connection
    if (!$taskStarted && in_array($response['header']['event'], ['task-failed', 'error'])) {
        $conn->close();
    }
}

npm install ws
npm install uuid

// See SSML support requirements in the note above

import fs from 'fs';
import WebSocket from 'ws';
import { v4 as uuid } from 'uuid'; // Used to generate UUIDs

// If you have not configured an environment variable, replace the following line with: const apiKey = "sk-xxx"
const apiKey = process.env.DASHSCOPE_API_KEY;
const url = 'wss://maas.qwencloudapi.com/api-ws/v1/inference/';
// Output file path
const outputFilePath = 'output.mp3';

// Clear the output file
fs.writeFileSync(outputFilePath, '');

// Create a WebSocket client
const ws = new WebSocket(url, {
  headers: {
    Authorization: `bearer ${apiKey}`,
    'X-DashScope-DataInspection': 'enable'
  }
});

let taskStarted = false;
let taskId = uuid();

ws.on('open', () => {
  console.log('Connected to WebSocket server');

  // Send the run-task command
  const runTaskMessage = JSON.stringify({
    header: {
      action: 'run-task',
      task_id: taskId,
      streaming: 'duplex'
    },
    payload: {
      task_group: 'audio',
      task: 'tts',
      function: 'SpeechSynthesizer',
      model: 'cosyvoice-v3-flash',
      parameters: {
        text_type: 'PlainText',
        voice: 'longanyang', // Voice
        format: 'mp3', // Audio format
        sample_rate: 22050, // Sample rate
        volume: 50, // Volume
        rate: 1, // Speech rate
        pitch: 1, // Pitch
        enable_ssml: true // Whether to enable the SSML feature. If enable_ssml is set to true, you can send the continue-task command only once. Otherwise, the error "Text request limit violated, expected 1." is reported.
      },
      input: {}
    }
  });
  ws.send(runTaskMessage);
  console.log('Sent run-task message');
});

const fileStream = fs.createWriteStream(outputFilePath, { flags: 'a' });
ws.on('message', (data, isBinary) => {
  if (isBinary) {
    // Write binary data to the file
    fileStream.write(data);
  } else {
    const message = JSON.parse(data);

    switch (message.header.event) {
      case 'task-started':
        taskStarted = true;
        console.log('Task has started');
        // Send continue-task command
        sendContinueTasks(ws);
        break;
      case 'task-finished':
        console.log('Task has finished');
        ws.close();
        fileStream.end(() => {
          console.log('File stream has been closed');
        });
        break;
      case 'task-failed':
        console.error('Task failed: ', message.header.error_message);
        ws.close();
        fileStream.end(() => {
          console.log('File stream has been closed');
        });
        break;
      default:
        // You can handle result-generated here
        break;
    }
  }
});

function sendContinueTasks(ws) {
  
  if (taskStarted) {
    // Send the continue-task command. When using the SSML feature, this command can be sent only once.
    const continueTaskMessage = JSON.stringify({
      header: {
        action: 'continue-task',
        task_id: taskId,
        streaming: 'duplex'
      },
      payload: {
        input: {
          // Special characters need to be escaped
          text: '<speak rate="2">My speaking rate is faster than a normal person\'s.</speak>'
        }
      }
    });
    ws.send(continueTaskMessage);
    
    // Send the finish-task command
    const finishTaskMessage = JSON.stringify({
      header: {
        action: 'finish-task',
        task_id: taskId,
        streaming: 'duplex'
      },
      payload: {
        input: {}
      }
    });
    ws.send(finishTaskMessage);
  }
}

ws.on('close', () => {
  console.log('Disconnected from the WebSocket server');
});

import com.fasterxml.jackson.databind.ObjectMapper;

import org.java_websocket.client.WebSocketClient;
import org.java_websocket.handshake.ServerHandshake;

import java.io.FileOutputStream;
import java.io.IOException;
import java.net.URI;
import java.nio.ByteBuffer;
import java.util.*;

/**
 * SSML feature notes:
 *     1. When sending the run-task command, set the enable_ssml parameter to true to enable SSML support.
 *     2. Send the text that contains SSML by using the continue-task command. You can send this command only once.
 *     3. Only cloned voices of the qwen-audio-3.0-tts-flash, qwen-audio-3.0-tts-plus, cosyvoice-v3-flash, and cosyvoice-v3-plus models, as well as system voices marked as SSML-supported in the voice list, support the SSML feature (for example, the longanyang voice of the cosyvoice-v3-flash model).
 */
public class TTSWebSocketClient extends WebSocketClient {
    private final String taskId = UUID.randomUUID().toString();
    private final String outputFile = "output_" + System.currentTimeMillis() + ".mp3";
    private boolean taskFinished = false;

    public TTSWebSocketClient(URI serverUri, Map<String, String> headers) {
        super(serverUri, headers);
    }

    @Override
    public void onOpen(ServerHandshake serverHandshake) {
        System.out.println("Connection successful");

        // Send run-task command
        // If enable_ssml is set to true, you can send the continue-task command only once.
        // Otherwise, you will get the error "Text request limit violated, expected 1."
        String runTaskCommand = "{ \"header\": { \"action\": \"run-task\", \"task_id\": \"" + taskId + "\", \"streaming\": \"duplex\" }, \"payload\": { \"task_group\": \"audio\", \"task\": \"tts\", \"function\": \"SpeechSynthesizer\", \"model\": \"cosyvoice-v3-flash\", \"parameters\": { \"text_type\": \"PlainText\", \"voice\": \"longanyang\", \"format\": \"mp3\", \"sample_rate\": 22050, \"volume\": 50, \"rate\": 1, \"pitch\": 1, \"enable_ssml\": true }, \"input\": {} }}";
        send(runTaskCommand);
    }

    @Override
    public void onMessage(String message) {
        System.out.println("Received message from server: " + message);
        try {
            // Parse JSON message
            Map<String, Object> messageMap = new ObjectMapper().readValue(message, Map.class);

            if (messageMap.containsKey("header")) {
                Map<String, Object> header = (Map<String, Object>) messageMap.get("header");

                if (header.containsKey("event")) {
                    String event = (String) header.get("event");

                    if ("task-started".equals(event)) {
                        System.out.println("Received task-started event from server");

                        // Send the continue-task command. When using the SSML feature, this command can be sent only once.
                        // Special characters need to be escaped.
                        sendContinueTask("<speak rate=\\\"2\\\">My speaking rate is faster than a normal person's.</speak>");

                        // Send the finish-task command
                        sendFinishTask();
                    } else if ("task-finished".equals(event)) {
                        System.out.println("Received task-finished event from server");
                        taskFinished = true;
                        closeConnection();
                    } else if ("task-failed".equals(event)) {
                        System.out.println("Task failed: " + message);
                        closeConnection();
                    }
                }
            }
        } catch (Exception e) {
            System.err.println("An exception occurred: " + e.getMessage());
        }
    }

    @Override
    public void onMessage(ByteBuffer message) {
        System.out.println("Size of received binary audio data: " + message.remaining());

        try (FileOutputStream fos = new FileOutputStream(outputFile, true)) {
            byte[] buffer = new byte[message.remaining()];
            message.get(buffer);
            fos.write(buffer);
            System.out.println("Audio data has been written to the local file " + outputFile);
        } catch (IOException e) {
            System.err.println("Failed to write audio data to local file: " + e.getMessage());
        }
    }

    @Override
    public void onClose(int code, String reason, boolean remote) {
        System.out.println("Connection closed: " + reason + " (" + code + ")");
    }

    @Override
    public void onError(Exception ex) {
        System.err.println("Error: " + ex.getMessage());
        ex.printStackTrace();
    }

    private void sendContinueTask(String text) {
        String command = "{ \"header\": { \"action\": \"continue-task\", \"task_id\": \"" + taskId + "\", \"streaming\": \"duplex\" }, \"payload\": { \"input\": { \"text\": \"" + text + "\" } }}";
        send(command);
    }

    private void sendFinishTask() {
        String command = "{ \"header\": { \"action\": \"finish-task\", \"task_id\": \"" + taskId + "\", \"streaming\": \"duplex\" }, \"payload\": { \"input\": {} }}";
        send(command);
    }

    private void closeConnection() {
        if (!isClosed()) {
            close();
        }
    }

    public static void main(String[] args) {
        try {
            // If you have not configured an environment variable, replace the following line with: String apiKey = "sk-xxx"
            String apiKey = System.getenv("DASHSCOPE_API_KEY");
            if (apiKey == null || apiKey.isEmpty()) {
                System.err.println("Please set the DASHSCOPE_API_KEY environment variable");
                return;
            }

            Map<String, String> headers = new HashMap<>();
            headers.put("Authorization", "bearer " + apiKey);
            TTSWebSocketClient client = new TTSWebSocketClient(new URI("wss://maas.qwencloudapi.com/api-ws/v1/inference/"), headers);

            client.connect();

            while (!client.isClosed() && !client.taskFinished) {
                Thread.sleep(1000);
            }
        } catch (Exception e) {
            System.err.println("Failed to connect to WebSocket service: " + e.getMessage());
            e.printStackTrace();
        }
    }
}

pip uninstall websocket-client
pip uninstall websocket
pip install websocket-client

# SSML feature notes:
#     1. When sending the run-task command, set the enable_ssml parameter to true to enable SSML support.
#     2. Send the text that contains SSML by using the continue-task command. You can send this command only once.
#     3. Only cloned voices of the qwen-audio-3.0-tts-flash, qwen-audio-3.0-tts-plus, cosyvoice-v3-flash, and cosyvoice-v3-plus models, as well as system voices marked as SSML-supported in the voice list, support the SSML feature (for example, the longanyang voice of the cosyvoice-v3-flash model).

import websocket
import json
import uuid
import os
import time


class TTSClient:
  def __init__(self, api_key, uri):
    """
  Initializes the TTSClient instance.

  Parameters:
    api_key (str): The API key for authentication.
    uri (str): The WebSocket service address.
  """
    self.api_key = api_key  # Replace with your API key.
    self.uri = uri  # Replace with your WebSocket address.
    self.task_id = str(uuid.uuid4())  # Generate a unique task ID.
    self.output_file = f"output_{int(time.time())}.mp3"  # Output audio file path.
    self.ws = None  # WebSocketApp instance.
    self.task_started = False  # Whether task-started is received.
    self.task_finished = False  # Whether task-finished/task-failed is received.

  def on_open(self, ws):
    """
  Callback function when the WebSocket connection is established.
  Sends the run-task command to start the speech synthesis task.
  """
    print("WebSocket connection established")

    # Construct the run-task command.
    run_task_cmd = {
      "header": {
        "action": "run-task",
        "task_id": self.task_id,
        "streaming": "duplex"
      },
      "payload": {
        "task_group": "audio",
        "task": "tts",
        "function": "SpeechSynthesizer",
        "model": "cosyvoice-v3-flash",
        "parameters": {
          "text_type": "PlainText",
          "voice": "longanyang",
          "format": "mp3",
          "sample_rate": 22050,
          "volume": 50,
          "rate": 1,
          "pitch": 1,
          # With enable_ssml: true, send continue-task only once
          "enable_ssml": True
        },
        "input": {}
      }
    }

    # Send the run-task command.
    ws.send(json.dumps(run_task_cmd))
    print("run-task command sent")

  def on_message(self, ws, message):
    """
  Callback function when a message is received.
  Handles text and binary messages separately.
  """
    if isinstance(message, str):
      # Process JSON text messages.
      try:
        msg_json = json.loads(message)
        print(f"Received JSON message: {msg_json}")

        if "header" in msg_json:
          header = msg_json["header"]

          if "event" in header:
            event = header["event"]

            if event == "task-started":
              print("Task started")
              self.task_started = True

              # Send the continue-task command. When using the SSML feature, this command can be sent only once.
              # Special characters need to be escaped.
              self.send_continue_task("<speak rate=\"2\">My speaking rate is faster than a normal person's.</speak>")

              # Send finish-task after continue-task is sent.
              self.send_finish_task()

            elif event == "task-finished":
              print("Task finished")
              self.task_finished = True
              self.close(ws)

            elif event == "task-failed":
              error_msg = msg_json.get("error_message", "Unknown error")
              print(f"Task failed: {error_msg}")
              self.task_finished = True
              self.close(ws)

      except json.JSONDecodeError as e:
        print(f"JSON parsing failed: {e}")
    else:
      # Process binary messages (audio data).
      print(f"Received binary message, size: {len(message)} bytes")
      with open(self.output_file, "ab") as f:
        f.write(message)
      print(f"Audio data has been written to the local file {self.output_file}")

  def on_error(self, ws, error):
    """Callback on error."""
    print(f"WebSocket error: {error}")

  def on_close(self, ws, close_status_code, close_msg):
    """Callback on close."""
    print(f"WebSocket closed: {close_msg} ({close_status_code})")

  def send_continue_task(self, text):
    """Sends the continue-task command with the text to be synthesized."""
    cmd = {
      "header": {
        "action": "continue-task",
        "task_id": self.task_id,
        "streaming": "duplex"
      },
      "payload": {
        "input": {
          "text": text
        }
      }
    }

    self.ws.send(json.dumps(cmd))
    print(f"Sent continue-task command, text content: {text}")

  def send_finish_task(self):
    """Sends the finish-task command to end the speech synthesis task."""
    cmd = {
      "header": {
        "action": "finish-task",
        "task_id": self.task_id,
        "streaming": "duplex"
      },
      "payload": {
        "input": {}
      }
    }

    self.ws.send(json.dumps(cmd))
    print("Sent finish-task command")

  def close(self, ws):
    """Actively closes the connection."""
    if ws and ws.sock and ws.sock.connected:
      ws.close()
      print("Connection actively closed")

  def run(self):
    """Starts the WebSocket client."""
    # Set request headers (authentication).
    header = {
      "Authorization": f"bearer {self.api_key}",
      "X-DashScope-DataInspection": "enable"
    }

    # Create a WebSocketApp instance.
    self.ws = websocket.WebSocketApp(
      self.uri,
      header=header,
      on_open=self.on_open,
      on_message=self.on_message,
      on_error=self.on_error,
      on_close=self.on_close
    )

    print("Listening for WebSocket messages...")
    self.ws.run_forever()  # Start the persistent connection listener.


# Example usage
if __name__ == "__main__":
  # If you have not configured an environment variable, replace the following line with: API_KEY = "sk-xxx"
  API_KEY = os.environ.get("DASHSCOPE_API_KEY")
  SERVER_URI = "wss://maas.qwencloudapi.com/api-ws/v1/inference/"

  client = TTSClient(API_KEY, SERVER_URI)
  client.run()