How to display error code in php

In PHP programming, errors are the norm. These errors can be caused by coding errors, server configuration, or incorrect user input. Regardless of the cause of the error, developers need to be aware of the error, investigate its cause, and fix it. In PHP, displaying error codes is an important debugging technique that helps developers quickly diagnose problems and find solutions.

PHP provides several ways to display error codes, including through the browser, logging, and through the command line interface (CLI). Below we will introduce these methods one by one.

1. Display PHP error codes through the browser

During the development and debugging stages, errors are usually output directly to the browser so that developers can check them in time. In order to enable this feature, you need to add the following code to the PHP script:

<?php
    ini_set(&#39;display_errors&#39;, 1);
    ini_set(&#39;display_startup_errors&#39;, 1);
    error_reporting(E_ALL);
?>

You can dynamically change PHP configuration options in the script by calling the ini_set() function. In the above code, we set the display_errors and display_startup_errors options to 1, which will enable displaying errors in the browser while the script is running. The error_reporting() function controls which errors will be caught and displayed.

At this point, when an error occurs when the PHP script is running, the error message will be displayed directly in the browser.

2. Using PHP Error Logging to Record Error Messages

In a production environment, outputting error messages directly in the browser may have a negative impact on users. Therefore, it is more common to log errors to a file. PHP provides a default logger that writes error messages to a log file using the error_log() function. The following code logs all error messages to the my-error.log file:

<?php
    ini_set(&#39;log_errors&#39;, 1);
    ini_set(&#39;error_log&#39;, &#39;/path/to/my-error.log&#39;);
?>

Since the error_log() function has three parameters (error message, error type, and log file path), you can use it to log Different types of error messages.

3. Showing PHP error messages through the command line interface

When running a PHP script through the command line interface, you can use the -d parameter to dynamically change the PHP configuration. The following example uses the -d parameter to set the error level:

php -d display_errors=on script.php

This command sets PHP errors to be displayed in the command line interface. When an error occurs while the script is running, it will be displayed directly in the terminal window.

Summary

No matter which method you use to display PHP error codes, following these best practices can ensure the safety and reliability of your code:

1. In production environment, disable the display of error messages to avoid exposing sensitive information to the user.
2. Use a logger to log error messages for debugging or monitoring system health.
3. Enable displaying error messages only when required for debugging or development.
4. Understand and follow PHP security best practices to prevent attackers from using incorrect information to attack the system.

By learning and correctly using PHP error code display technology, developers can identify problems faster and better ensure the reliability and security of the code.

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