Xdebug Getting Started Guide: Novice Becomes PHP Debugging Master in seconds

Xdebug is a powerful PHP debugging extension that gives you deep insight into the execution of your code to solve problems quickly and efficiently. This guide will lead you to understand the installation and use of Xdebug from the beginning, allowing you to become a php debugging master.

Install Xdebug

1. Download the Xdebug extension, compatible with your PHP version and operating system .
2. Extract the Xdebug file to the PHP extension directory (usually /usr/local/lib/php/extens<strong class="keylink">io</strong>ns/).
3. Edit the php.ini file and add the line zend_extension=xdebug.so.
4. Restart the Apache or PHP service for the changes to take effect.

Enable Xdebug

There are two ways to enable Xdebug:

• Add the XDEBUG_SESSION_START parameter to the URL: For example, <strong class="keylink">Http</strong>://example.com/index.php?XDEBUG_SESSION_START
• Using the Xdebug IDE Configurator: Install the Xdebug IDE Configurator extension in your IDE and it will automatically handle enablement and configuration.

Using the Xdebug toolbar

After enabling Xdebug, you will see the Xdebug Tools bar in the upper right corner of the browser. It provides the following information:

• Step view: Display function call stack and local variables.
• Variable view: Displays the value of declared variables.
• Execution time: Display the execution time of the script.
• Memory Usage: Displays the amount of allocated memory.

Set breakpoint

Breakpoints pause script execution at specific lines of code, allowing you to inspect variable values ​​and diagnose problems. There are two ways to set breakpoints:

• Using the Xdebug toolbar: Click the line number next to a line of code so it turns blue.
• Use IDE: Set breakpoints in the IDE and Xdebug will automatically synchronize.

View variables

The Xdebug toolbar allows you to inspect the values ​​of local and global variables. Click a variable name to view its type, value, and memory address. You can also use the var_dump() or print_r() function to print variable information in the console.

Analyzing stack trace

When a script encounters an error, Xdebug displays a stack trace that provides clues as to the source of the error. It includes the following information:

• Function calling sequence
• Parameters and return types of each function
• Wrong line number and file

Optimize performance

Xdebug may affect script performance, especially when debugging is enabled. The following tips can minimize the impact:

• Enable debugging only when needed.
• Exclude code that does not require debugging through the configuration file.
• Use the XDEBUG_PROFILE parameter to record performance data.

Advanced usage

Xdebug provides many advanced features, including:

• Coverage analysis: Determine which part of the code has been executed.
• Step in/out: Execute the code line by line and view variable values.
• Remote debugging: Debug the code on the remote server on the local computer.

Other resources

• Official Xdebug documentation: https://xdebug.org/docs/
• Xdebug IDE configurator: https://xdebug.org/wizard.php
• PHP debugging tips: https://www.php.net/manual/en/debugger.techniques.php

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