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Business Disaster Recovery Scheme (Web and App)
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Last updated: 2025-06-05 10:51:17
Business Disaster Recovery Scheme (Web and App)
Last updated: 2025-06-05 10:51:17
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To ensure that customers' business processes run normally in case of an exception in the Captcha server, we provide the following business disaster recovery schemes.
Note:
No billing is incurred when verifying any disaster recovery tickets generated in the disaster recovery schemes.

Business client (frontend) disaster recovery

1. Define the JS load error handling function.
// The error handling function ensures that event processes run normally in case of JS load or initialization errors.
// Define the function before the script loads
function loadErrorCallback() {
    var appid = 'CaptchaAppId';
    // Generate a disaster recovery ticket or use another handling technique
    var ticket = 'trerror_1001_' + appid + '_' + Math.floor(new Date().getTime() / 1000);
    callback({
        ret: 0,
        randstr: '@'+ Math.random().toString(36).substr(2),
        ticket,
        errorCode: 1001,
        errorMessage: 'jsload_error',
    });
}
2. Call the JS load error handling function if an error is caught during the CAPTCHA instance call.
try {
    // Generate a CAPTCHA object
    var captcha = new TencentCaptcha(document.getElementById('cap_iframe'), 'Your CAPTCHA's CaptchaAppId', callback, {});
    // Call the method to show the CAPTCHA
    captcha.show(); 
} catch (error) {
    // Load error. Call the CAPTCHA js load error handling function.
    loadErrorCallback();
}
3. Define the CAPTCHA callback function so the handling is based on ticket and errorCode (instead of ret). For errorCode definitions, please see Web Frontend Integration.
function callback(res) {
    // res (CAPTCHA is closed by the user) = {ret: 2, ticket: null}
    // res (Verification is successful) = {ret: 0, ticket: "String", randstr: "String"}
    // res (Request error. A disaster recovery ticket with the prefix trerror_ is returned.) = {ret: 0, ticket: "String", randstr: "String",  errorCode: Number, errorMessage: "String"}
    if (res.ticket){
        // Handle based on errorCode
        if(res.errorCode === xxxxx){
           // Customize the disaster recovery logic (for example, skip this verification)
        }
      }
}

Business server (backend) disaster recovery

In case of an exception when requesting the ticket verification API, the business server needs to handle the exception (for example, skip this verification) to avoid affecting business processes due to abnormal API responses, request timeouts, or the service not responding. The following are some abnormal responses that require disaster recovery on the business side.
Request timeout or service not responding.
Exception returned. Code is InternalError. Example:
{
  "Response": {
      "Error": {
          "Code": "InternalError",
          "Message": "An internal error has occurred. Retry your request. If the problem persists, contact us."
      },
      "RequestId": "xxxxxxxxxxx"
  }
}
Service internal error. CaptchaCode is 26. Example:
{
  "Response": {
      "CaptchaCode": 26,
      "CaptchaMsg": "System busy. For more information, please see the Captcha documentation. Search for the keyword "DescribeCaptchaResult", and check the description of the CaptchaCode field in the output parameters",
      "EvilLevel": 0,
      "GetCaptchaTime": 0,
      "RequestId": "xxxxxxxxxxx"
  },
  "retcode": 0,
  "retmsg": "ok"
}

More information

You can log in to the Captcha console, and click Quick Consulting in the upper right corner to learn more.
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