How I Debug WordPress Code: A Step-by-Step Guide

Debugging WordPress code is an essential skill for developers and site administrators. Whether you’re trying to fix a bug, improve performance, or develop new features, knowing how to identify and solve issues in your WordPress code can save you a lot of time and frustration.

In this blog post, we’ll explore several methods and tools that you can use to debug WordPress code. We’ll also provide screenshots to guide you through the process.

1. Enable WordPress Debugging

The first step in debugging WordPress is to enable the built-in debugging mode. WordPress comes with a set of constants that you can define in the wp-config.php file to control how errors and warnings are displayed.

Step-by-Step Instructions:

1. Locate the wp-config.php file in the root directory of your WordPress installation.
2. Open the file in a text editor.
3. Add the following lines of code:

   define( 'WP_DEBUG', true );
   define( 'WP_DEBUG_LOG', true );
   define( 'WP_DEBUG_DISPLAY', false );

• WP_DEBUG: Enables debugging mode.
• WP_DEBUG_LOG: Saves errors to a debug.log file located in the wp-content directory.
• WP_DEBUG_DISPLAY: Prevents errors from being displayed on the website (useful for live sites).

1. Save the file and re-upload it to your server if you’re editing locally.

(Replace with an actual screenshot of the wp-config.php file with the debug constants highlighted.)

Result:

With debugging enabled, WordPress will now log errors and warnings to a file called debug.log in the wp-content directory. You can review this file to find detailed information about any issues on your site.

2. Use the Query Monitor Plugin

Query Monitor is a powerful tool for debugging WordPress sites. It provides detailed information about database queries, PHP errors, hooks, and more directly from the WordPress admin bar.

Step-by-Step Instructions:

1. Install and activate the Query Monitor plugin from the WordPress Plugin Repository.
2. After activation, you’ll see a new menu in the WordPress admin bar labeled “Query Monitor.”
3. Click on the Query Monitor menu to view detailed information about the current page.

• Queries: View all database queries and identify any slow or duplicated ones.
• Hooks: Check which hooks are being triggered on the current page.
• Errors: See PHP errors, warnings, and notices.

(Replace with an actual screenshot of the Query Monitor interface showing queries and errors.)

Result:

Query Monitor helps you identify performance bottlenecks and coding errors by providing a wealth of information directly within the WordPress admin.

3. Debugging JavaScript and CSS

JavaScript and CSS issues can often cause parts of your WordPress site to break or not function as expected. Using browser developer tools is the best way to debug these types of issues.

Step-by-Step Instructions:

1. Open your browser’s developer tools (usually accessible by pressing F12 or right-clicking on the page and selecting “Inspect”).
2. Navigate to the “Console” tab to view JavaScript errors. The console will display errors, warnings, and messages that can help you identify issues.
3. Use the “Elements” tab to inspect your site’s HTML and CSS. Here, you can see which CSS rules are being applied and make live edits to test fixes.
4. Check the “Network” tab to monitor HTTP requests, which can help you debug issues with resources not loading or returning errors.

(Replace with an actual screenshot of the browser developer tools highlighting the Console and Network tabs.)

Result:

Browser developer tools allow you to debug client-side issues in real-time, making it easier to identify and fix JavaScript and CSS problems.

4. Using Error Logs

Sometimes, the errors might not be apparent in the debug.log or the front end. In such cases, accessing the server error logs can provide additional information.

Step-by-Step Instructions:

1. Access your server’s control panel (e.g., cPanel, Plesk) or connect via SSH.
2. Navigate to the logs section and find the error logs. These logs are often located in the logs directory or accessible directly from the control panel.
3. Look for recent errors corresponding to the times when the issues occurred.

(Replace with an actual screenshot of server error logs showing a recent error.)

Result:

Server error logs provide deeper insights into issues that may not be captured by WordPress’s own logging, helping you diagnose server-level problems.

5. Debugging with Xdebug

For more advanced debugging, especially if you’re developing custom themes or plugins, using a PHP debugger like Xdebug is invaluable.

Step-by-Step Instructions:

1. Install Xdebug on your local development environment. This usually involves updating your php.ini file with the Xdebug extension.
2. Set up your IDE (e.g., PhpStorm, VS Code) to listen for Xdebug connections.
3. Place breakpoints in your code where you want the execution to pause. This allows you to inspect variables, step through code, and identify where things are going wrong.

(Replace with an actual screenshot of Xdebug in action within an IDE, showing breakpoints and variable inspection.)

Result:

Using Xdebug provides a deep level of control over your debugging process, allowing you to inspect and manipulate code execution in real-time.

Conclusion

Debugging WordPress code is a critical skill for anyone managing or developing a WordPress site. By enabling WordPress’s built-in debugging features, using plugins like Query Monitor, utilizing browser developer tools, and exploring server logs, you can identify and fix issues efficiently. For advanced users, tools like Xdebug provide even more control over the debugging process.

Remember, a well-debugged site is a well-functioning site. Happy debugging!

Feel free to replace the placeholder URLs with actual screenshots to make the post more visually engaging and informative.

If you need me to custom code something for your WooCommerce store I might need to debug things, why not hire me. Jesus that was a reach to put a sales messages in this blog post.

Photo by Krzysztof Niewolny on Unsplash