Practical summary of error handling in PHP language development

In the PHP language development process, error handling is a very important task. A good error handling can effectively improve the stability and reliability of the program, while also improving the programmer's efficiency and user experience. However, different error handling methods have different effects and applicable occasions in practical applications. This article will provide a practical summary of common error handling methods in PHP language development for developers' reference.

1. Error level and error code

In PHP, error level (error_reporting) and error code (error code) are common error handling mechanisms. The error level defines the type and degree of errors that occur during program operation, and the error code is used to identify the specific error type and cause. In actual development, we use different processing methods according to different error levels and error codes.

Common error levels include:

• E_ERROR: serious error, execution must be terminated once it occurs;
• E_WARNING: warning message, the program can continue to execute, but An exception may occur;
• E_NOTICE: Attention information, the program can continue to execute, but attention is required;
• E_STRICT: Warning information in strict mode;
• E_DEPRECATED: Outdated information , indicating that a function or method is obsolete and is no longer recommended for use.

Common error codes include:

• 100: General error;
• 101: System error;
• 102: Application Error;
• 103: Code error;
• 104: Framework error.

2. PHP error handling mechanism

PHP provides a variety of error handling mechanisms, including try-catch mechanism, error message triggering function, error message archiving function, etc. In PHP, we can choose different processing methods according to specific situations.

1. try-catch mechanism

The try-catch mechanism is a common mechanism for handling exceptions in PHP. By using try statement blocks and catch statement blocks, it can be effective Handle exceptions that occur during program execution.

The try statement block contains code or method calls that may cause exceptions, while the catch statement block is used to capture and handle these exceptions. If the code in the try block executes normally, the catch block will be skipped. But if an exception occurs in the try statement block, the program will jump to the corresponding catch statement block for processing.

Sample code:

try{

//可能引发异常的代码

}catch(Exception $e){

//捕获并处理异常

}

2. trigger Function

PHP provides some functions for triggering and processing error information, such as trigger_error(), user_error(), error_log(), etc. These functions can easily record and handle exceptions that occur during the running of PHP programs.

Sample code:

if($num < 0){

trigger_error('Invalid number', E_USER_ERROR);

}

3. Archive function

PHP also provides some functions for archiving error messages and exceptions, such as error_log(), debug_backtrace(), set_error_handler(), etc. These functions can record relevant error information and stack information when an abnormality occurs when a PHP program is running, making it easier for programmers to troubleshoot and solve problems.

Sample code:

function ErrorHandler($errno, $errmsg, $filename, $linenum){

error_log(sprintf("[%s] %s in %s on line %d.", date('Y-m-d H:i:s'), $errmsg, $filename, $linenum), 3, 'error.log');
die();

}
set_error_handler("ErrorHandler");

3. Practical summary of PHP error handling

In PHP development, error handling is a very important task. Good error handling can improve the stability and reliability of the program, but different error handling methods have different effects and applicable situations in actual applications. Let's summarize the advantages, disadvantages and applicable occasions of various error handling methods.

1. try-catch mechanism

The try-catch mechanism is suitable for handling exceptions thrown by code segments. Since this mechanism is inherited from object-oriented programming, it is also suitable for handling exceptions in object-based programs. Common application scenarios include:

• Exception handling in database operations;
• Exception handling in file operations;
• Exception handling in network communication;
• Exception handling in object-based applications.

Advantages:

• Can accurately capture and handle exceptions;
• Convenient to record and output exception information;
• Applicable for object-based program development.

Disadvantages:

• The code requires more try-catch code blocks, resulting in code redundancy;
• When dealing with complex exceptions, the code The structure may become complex and difficult to maintain;
• Exception catching may be less efficient in high concurrency situations.

2. Trigger function

The trigger function is suitable for handling errors and exceptions that occur during program running. It can be used anywhere in a program to quickly log and handle errors and exceptions. Common application scenarios include:

• Custom error handling;
• Program environment detection;
• Conditional branch judgment, etc.

Advantages:

• can be easily called and used;
• can be used anywhere in the program;
• is applicable for simple errors and exceptions.

shortcoming:

• May cause unnecessary warning messages;
• Unable to obtain detailed error information and stack information;
• Accurate handling of complex errors and exceptions may not be possible .

3. Archive function

The archive function is suitable for archiving error messages and exceptions during program running. It can record program errors and exceptions to facilitate programmers to troubleshoot and solve problems. Common application scenarios include:

• system log recording;
• abnormal situation recording;
• program debugging information recording, etc.

Advantages:

• Convenient to record and troubleshoot errors and exceptions;
• Can obtain detailed error information and stack information;
• Can quickly locate and solve program errors and exceptions.

Disadvantages:

• The archive function may have an impact on system performance;
• Need to handle system errors caused by the archive function in a timely manner through other means;
• Archive functions cannot handle errors and exceptions accurately.

4. Summary

Error handling in PHP language development is a very important task. Different error handling methods have different effects and applicable occasions in practical applications. In the actual development process, we should choose different processing methods according to the specific situation to ensure the stability and reliability of the program. Through the introduction of this article, I believe that readers will have a more comprehensive and in-depth understanding of the PHP error handling mechanism, and will be enlightened on how to choose and use different error handling methods.

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