Losing REST over Ajax Errors?

In many Ajax examples, the error response is handled as follows (pseudocode):

xhr.onreadystatechange = function() {
  if (xhr.readyState == 4) {
    if (xhr.status == 200) {
      // 处理返回数据（例如：解析XML）
      // 基于自定义/临时错误检测检查结果状态（通常是0表示失败，1表示成功）
      // 处理/报告错误，或根据返回数据采取其他操作
    }
  }
};

This approach works, but as applications grow and the need for useful error reporting (and error avoidance!) increases, this simple Boolean error checking can quickly become difficult to manage. Imagine:

1. Developer 1: "What does error code 7 mean?"
2. Developer 2: "Well, wait, I'm sure where we wrote it..."

Don't worry, there is a smarter alternative that you will use every time you load your browser - HTTP status code (if you don't want to read another RFC, check out Mark Pilgrim's humorous abridged list).

In the previous example, I added a switch block to handle some of the most useful status codes when handling JavaScript HTTP request responses:

xhr.onreadystatechange = function() {
  if (xhr.readyState == 4) {
    switch (xhr.status) {
      case 200: // OK!
        /* 如果请求是创建新资源（例如将项目发布到数据库），则可以返回“201 已创建”状态码 */
        break;
      case 304: // 未修改
        /* 当你的Ajax小部件正在检查更新内容时使用，例如Twitter界面 */
        break;
      case 400: // 错误请求
        /* 类似于对服务器不支持的JS接口请求的安全网。“你的浏览器发出了服务器无法理解的请求” */
        break;
      case 409: // 冲突
        /* 你的JavaScript请求可能尝试更新数据库记录，但由于冲突而失败（例如：必须唯一的字段） */
        break;
      case 503: // 服务不可用
        /* 此请求依赖的资源当前不可用（例如：文件被另一个进程锁定） */
        break;
    }
  }
};

So, next time you want to add <status>1</status> or something like that in your XML response, take a deeper look at the HTTP status code. This may be the first step to getting a REST, which is definitely a good thing™.

FAQs about AJAX Errors (FAQs)

What is a 400 Error Request in AJAX?

The 400 erroneous request in AJAX is a client error, which occurs when the server cannot understand the request due to invalid syntax. This error can be triggered by a variety of reasons, such as incorrect format of the data sent in the request, too large in size, or a problem with the server itself. It is important to debug errors to identify the root cause and apply the appropriate solution.

How to debug 400 error requests in AJAX?

Debugging 400 error requests in AJAX includes several steps. First, check the syntax of the AJAX request. Make sure the URL, header, and data are formatted correctly. Use browser developer tools to check network requests and responses. If the error persists, check if there are any problems with the server-side code.

How to fix 400 erroneous requests in AJAX?

Fixing 400 erroneous requests in AJAX depends on the cause of the error. If the error is due to incorrect data format, make sure the data is correctly formatted to JSON or XML. If the request size is too large, consider reducing the request size. If the errors are caused by server-side issues, check for any errors in the server logs and fix them accordingly.

Why does my jQuery AJAX POST request receive 400 error requests?

The 400 erroneous request in jQuery AJAX POST can be caused by a variety of reasons. The most common reason is the incorrect data format. Make sure the data is correctly formatted to JSON or XML. Other reasons may include server problems or request size too large.

How to prevent 400 erroneous requests in AJAX?

Preventing 400 erroneous requests in AJAX includes ensuring that the AJAX request is formatted correctly. This includes URLs, headers, and data. Also, make sure the request size is not large. Check regularly for any errors in the server logs and fix them immediately.

How does 400 erroneous requests in AJAX affect my website?

400 erroneous requests in AJAX may negatively affect your website by causing feature issues. This can lead to poor user experience and can lead to user or customer churn. Therefore, it is very important to identify and fix any 400 error requests in a timely manner.

How to handle 400 erroneous requests in AJAX in WordPress?

Handling 400 erroneous requests in AJAX in WordPress includes checking AJAX requests and server-side code. Make sure the AJAX request is formatted correctly and the server-side code is free of errors. Use WordPress debugging tools to help identify and fix any issues.

Why does my WordPress AJAX call receive 400 error requests?

The 400 erroneous requests in WordPress AJAX calls can be caused by a variety of reasons. The most common reason is the incorrect data format. Make sure the data is correctly formatted to JSON or XML. Other reasons may include server problems or request size too large.

How to debug 400 error requests in WordPress AJAX call?

Debug 400 erroneous requests in WordPress AJAX calls include checking AJAX requests and server-side code. Use WordPress debugging tools to help identify and fix any issues. Also check the server log for any errors.

How to fix 400 erroneous requests in WordPress AJAX calls?

Fixing 400 error requests in WordPress AJAX calls involves identifying the cause of the error and applying the appropriate solution. This may include correcting the data format, reducing the request size, or fixing any server-side issues. Use WordPress debugging tools to help identify and fix any issues.

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