Lyrics Generation Callbacks

When you submit a task to the Lyrics Generation API, you can use the callBackUrl parameter to set a callback URL. When the task is completed, the system will automatically push the results to your specified address.

Callback Mechanism Overview

The callback mechanism eliminates the need to poll the API for task status. The system will proactively push task completion results to your server.

Callback Timing

The system will send callback notifications in the following situations:

Lyrics generation task completed successfully
Lyrics generation task failed
Errors occurred during task processing

Callback Method

HTTP Method: POST
Content Type: application/json
Timeout Setting: 15 seconds

Callback Request Format

When the task is completed, the system will send a POST request to your callBackUrl in the following format:

{
  "code": 200,
  "msg": "All generated successfully.",
  "data": {
    "callbackType": "complete",
    "taskId": "11dc****8b0f",
    "data": [
      {
        "text": "[Verse]\nWalking through the city's darkest night\nWith dreams burning like a blazing fire",
        "title": "Iron Man",
        "status": "complete",
        "errorMessage": ""
      },
      {
        "text": "[Verse]\nWind is calling out my name\nSteel armor shining in the light",
        "title": "Iron Man",
        "status": "complete",
        "errorMessage": ""
      }
    ]
  }
}

Status Code Description

code

integer

required

Callback status code indicating task processing result:

Status Code	Description
200	Success - Lyrics generation completed
400	Bad Request - Parameter error, content violation, etc.
451	Download Failed - Unable to download related files
500	Server Error - Please try again later

msg

string

required

Status message providing detailed status description

data.callbackType

string

required

Callback type indicating the current callback stage:

complete: Lyrics generation completed
error: Task failed

data.taskId

string

required

Task ID, consistent with the taskId returned when you submitted the task

data.data

array

Lyrics generation result information, returns multiple lyrics variants on success

data.data[].text

string

Generated lyrics content, including song structure markers (e.g., [Verse], [Chorus], etc.)

data.data[].title

string

Lyrics title

data.data[].status

string

Lyrics generation status:

complete: Generation completed
failed: Generation failed

data.data[].errorMessage

string

Error message, contains specific error description when status is failed

Callback Reception Examples

Here are example codes for receiving callbacks in popular programming languages:

Node.js
Python
PHP

const express = require('express');
const app = express();

app.use(express.json());

app.post('/generate-lyrics-callback', (req, res) => {
  const { code, msg, data } = req.body;
  
  console.log('Received lyrics generation callback:', {
    taskId: data.taskId,
    callbackType: data.callbackType,
    status: code,
    message: msg
  });
  
  if (code === 200) {
    // Task completed successfully
    console.log('Lyrics generation completed');
    const lyricsData = data.data || [];
    
    console.log(`Generated ${lyricsData.length} lyrics variants:`);
    lyricsData.forEach((lyrics, index) => {
      console.log(`Lyrics variant ${index + 1}:`);
      console.log(`  Title: ${lyrics.title}`);
      console.log(`  Status: ${lyrics.status}`);
      if (lyrics.status === 'complete') {
        console.log(`  Lyrics content:\n${lyrics.text}`);
      } else {
        console.log(`  Error message: ${lyrics.errorMessage}`);
      }
    });
    
    // Process generated lyrics
    // Can save to database, files, etc.
    
  } else {
    // Task failed
    console.log('Lyrics generation failed:', msg);
    
    // Handle failure cases...
    if (code === 400) {
      console.log('Parameter error or content violation');
    } else if (code === 451) {
      console.log('File download failed');
    } else if (code === 500) {
      console.log('Server internal error');
    }
  }
  
  // Return 200 status code to confirm callback received
  res.status(200).json({ status: 'received' });
});

app.listen(3000, () => {
  console.log('Callback server running on port 3000');
});

from flask import Flask, request, jsonify

app = Flask(__name__)

@app.route('/generate-lyrics-callback', methods=['POST'])
def handle_callback():
    data = request.json
    
    code = data.get('code')
    msg = data.get('msg')
    callback_data = data.get('data', {})
    task_id = callback_data.get('taskId')
    callback_type = callback_data.get('callbackType')
    lyrics_data = callback_data.get('data', [])
    
    print(f"Received lyrics generation callback: {task_id}, type: {callback_type}, status: {code}, message: {msg}")
    
    if code == 200:
        # Task completed successfully
        print("Lyrics generation completed")
        
        print(f"Generated {len(lyrics_data)} lyrics variants:")
        for i, lyrics in enumerate(lyrics_data):
            print(f"Lyrics variant {i + 1}:")
            print(f"  Title: {lyrics.get('title')}")
            print(f"  Status: {lyrics.get('status')}")
            if lyrics.get('status') == 'complete':
                print(f"  Lyrics content:\n{lyrics.get('text')}")
                
                # Save lyrics to file example
                try:
                    filename = f"lyrics_{task_id}_{i + 1}.txt"
                    with open(filename, "w", encoding="utf-8") as f:
                        f.write(f"Title: {lyrics.get('title')}\n\n")
                        f.write(lyrics.get('text'))
                    print(f"Lyrics saved as {filename}")
                except Exception as e:
                    print(f"Lyrics save failed: {e}")
            else:
                print(f"  Error message: {lyrics.get('errorMessage')}")
                
    else:
        # Task failed
        print(f"Lyrics generation failed: {msg}")
        
        # Handle failure cases...
        if code == 400:
            print("Parameter error or content violation")
        elif code == 451:
            print("File download failed")
        elif code == 500:
            print("Server internal error")
    
    # Return 200 status code to confirm callback received
    return jsonify({'status': 'received'}), 200

if __name__ == '__main__':
    app.run(host='0.0.0.0', port=3000)

<?php
header('Content-Type: application/json');

// Get POST data
$input = file_get_contents('php://input');
$data = json_decode($input, true);

$code = $data['code'] ?? null;
$msg = $data['msg'] ?? '';
$callbackData = $data['data'] ?? [];
$taskId = $callbackData['taskId'] ?? '';
$callbackType = $callbackData['callbackType'] ?? '';
$lyricsData = $callbackData['data'] ?? [];

error_log("Received lyrics generation callback: $taskId, type: $callbackType, status: $code, message: $msg");

if ($code === 200) {
    // Task completed successfully
    error_log("Lyrics generation completed");
    
    error_log("Generated " . count($lyricsData) . " lyrics variants:");
    foreach ($lyricsData as $index => $lyrics) {
        error_log("Lyrics variant " . ($index + 1) . ":");
        error_log("  Title: " . ($lyrics['title'] ?? ''));
        error_log("  Status: " . ($lyrics['status'] ?? ''));
        
        if (($lyrics['status'] ?? '') === 'complete') {
            error_log("  Lyrics content:\n" . ($lyrics['text'] ?? ''));
            
            // Save lyrics to file example
            try {
                $filename = "lyrics_{$taskId}_" . ($index + 1) . ".txt";
                $content = "Title: " . ($lyrics['title'] ?? '') . "\n\n" . ($lyrics['text'] ?? '');
                file_put_contents($filename, $content);
                error_log("Lyrics saved as $filename");
            } catch (Exception $e) {
                error_log("Lyrics save failed: " . $e->getMessage());
            }
        } else {
            error_log("  Error message: " . ($lyrics['errorMessage'] ?? ''));
        }
    }
    
} else {
    // Task failed
    error_log("Lyrics generation failed: $msg");
    
    // Handle failure cases...
    if ($code === 400) {
        error_log("Parameter error or content violation");
    } elseif ($code === 451) {
        error_log("File download failed");
    } elseif ($code === 500) {
        error_log("Server internal error");
    }
}

// Return 200 status code to confirm callback received
http_response_code(200);
echo json_encode(['status' => 'received']);
?>

Best Practices

Callback URL Configuration Recommendations

Use HTTPS: Ensure your callback URL uses HTTPS protocol for secure data transmission
Verify Source: Verify the legitimacy of the request source in callback processing
Idempotent Processing: The same taskId may receive multiple callbacks, ensure processing logic is idempotent
Quick Response: Callback processing should return a 200 status code as quickly as possible to avoid timeout
Asynchronous Processing: Complex business logic should be processed asynchronously to avoid blocking callback response
Lyrics Storage: Lyrics content should be saved to database or file system promptly

Important Reminders

Callback URL must be a publicly accessible address
Server must respond within 15 seconds, otherwise it will be considered a timeout
If 3 consecutive retries fail, the system will stop sending callbacks
Please ensure the stability of callback processing logic to avoid callback failures due to exceptions
Pay attention to content policy compliance to avoid generation failures due to policy violations
Lyrics content may contain special characters, pay attention to encoding handling

Troubleshooting

If you do not receive callback notifications, please check the following:

Network Connection Issues

Confirm that the callback URL is accessible from the public network
Check firewall settings to ensure inbound requests are not blocked
Verify that domain name resolution is correct

Server Response Issues

Ensure the server returns HTTP 200 status code within 15 seconds
Check server logs for error messages
Verify that the interface path and HTTP method are correct

Content Format Issues

Confirm that the received POST request body is in JSON format
Check that Content-Type is application/json
Verify that JSON parsing is correct

Lyrics Processing Issues

Note that lyrics content may contain line breaks and special characters
Ensure text encoding is handled correctly (recommend using UTF-8)
Verify lyrics save paths and permissions
Note whether lyrics content complies with content policies

Alternative Solution

If you cannot use the callback mechanism, you can also use polling:

Poll Query Results

Use the get lyrics generation details endpoint to regularly query task status. We recommend querying every 30 seconds.

Generate Music

Generate Lyrics

WAV Conversion

Vocal Removal

Music Video Generation

Account Management

File Upload API

Lyrics Generation Callbacks

Callback Mechanism Overview

Callback Timing

Callback Method

Callback Request Format

Status Code Description

Callback Reception Examples

Best Practices

Callback URL Configuration Recommendations

Important Reminders

Troubleshooting

Alternative Solution

Poll Query Results

Generate Music

Generate Lyrics

WAV Conversion

Vocal Removal

Music Video Generation

Account Management

File Upload API

​Callback Mechanism Overview

​Callback Timing

​Callback Method

​Callback Request Format

​Status Code Description

​Callback Reception Examples

​Best Practices

​Callback URL Configuration Recommendations

​Important Reminders

​Troubleshooting

​Alternative Solution

Poll Query Results

Callback Mechanism Overview

Callback Timing

Callback Method

Callback Request Format

Status Code Description

Callback Reception Examples

Best Practices

Callback URL Configuration Recommendations

Important Reminders

Troubleshooting

Alternative Solution