New error handling functions in PHP7: How to better manage errors and exceptions?

Some powerful error handling functions have been added to PHP7, making developers more flexible and efficient in managing errors and exceptions. This article introduces these new error handling functions and provides some specific code examples to demonstrate how to better manage errors and exceptions.

1. Error handling function

1. set_error_handler(callback)
   This function is used to register a custom error handling function when an error occurs , this function will be called to process. Developers can record error logs, send error emails and other operations in this custom function. The following is a sample code:

function customErrorHandler($errno, $errstr, $errfile, $errline) {
    // 记录错误日志
    error_log("Error: $errstr in $errfile on line $errline");
   
    // 发送错误邮件
    $to = "admin@example.com";
    $subject = "PHP Error";
    $message = "An error occurred: $errstr in $errfile on line $errline";
    mail($to, $subject, $message);
}
set_error_handler("customErrorHandler");

2. set_exception_handler(callback)
   This function is used to register a custom exception handling function. When an exception occurs, This function will be called to handle it. Developers can record exception logs, send exception emails and other operations in this custom function. The following is a sample code:

function customExceptionHandler($exception) {
    // 记录异常日志
    error_log("Exception: " . $exception->getMessage());
   
    // 发送异常邮件
    $to = "admin@example.com";
    $subject = "PHP Exception";
    $message = "An exception occurred: " . $exception->getMessage();
    mail($to, $subject, $message);
}
set_exception_handler("customExceptionHandler");

3. error_reporting(level)
   This function is used to set the level of error reporting. Developers can control whether error messages are displayed and logged by setting different levels. Here are some commonly used error reporting levels:

• E_ALL: Display and log all errors (default).
• E_ERROR: Only fatal errors are displayed and logged.
• E_WARNING: Display and log warnings and fatal errors.
• E_NOTICE: Display and log notifications, warnings, and fatal errors.
• E_NONE: Do not display or log any errors.

2. Error handling example

Below we will use an example to demonstrate how to use these error handling functions.

Suppose we have a function to upload pictures. Users can upload pictures through a form and save them to the server. We hope to be able to handle any errors and exceptions that may occur during the upload process, and give users a clear error message.

First, we set up a custom error handling function to record error logs:

function customErrorHandler($errno, $errstr, $errfile, $errline) {
    // 记录错误日志
    error_log("Error: $errstr in $errfile on line $errline");

    // 返回一个错误提示给用户
    echo "上传失败，请稍后重试。";
}
set_error_handler("customErrorHandler");

Then, we set up a custom exception handling function to record exception logs:

function customExceptionHandler($exception) {
    // 记录异常日志
    error_log("Exception: " . $exception->getMessage());

    // 返回一个异常提示给用户
    echo "上传失败，请稍后重试。";
}
set_exception_handler("customExceptionHandler");

Finally, we write the code to upload images, and catch and handle errors and exceptions where they may occur:

try {
    // 检查图片文件是否上传成功
    if ($_FILES["file"]["error"] != UPLOAD_ERR_OK) {
        throw new Exception("上传失败");
    }
    
    // 检查文件类型是否合法
    $allowedTypes = ["image/jpeg", "image/png"];
    if (!in_array($_FILES["file"]["type"], $allowedTypes)) {
        throw new Exception("文件类型不支持");
    }

    // 将上传的文件保存到服务器上
    $destination = "uploads/" . $_FILES["file"]["name"];
    move_uploaded_file($_FILES["file"]["tmp_name"], $destination);

    // 返回上传成功提示给用户
    echo "上传成功";
} catch (Exception $e) {
    // 处理异常
    $error = $e->getMessage();
    error_log("Exception: $error");

    // 返回一个错误提示给用户
    echo "上传失败，请稍后重试。";
}

Through the above code, we achieve a safe and reliable image upload Function. Whether errors or exceptions occur, we can catch and handle them and return a clear error message to the user.

Summary

The new error handling functions in PHP7 provide developers with the ability to better manage errors and exceptions. By setting custom error handling functions and exception handling functions, developers can flexibly handle various errors and exceptions, including recording error logs, sending error emails, and other operations. We hope that the introduction and examples in this article can help readers better manage errors and exceptions and improve development efficiency.

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