WordPress Execution Path

Initial entry point of WordPress

It loads the wp-blog-header.php file, which kicks off WordPress execution.

This file (/wp-blog-header.php) does followings:

1. includes /wp-load.php file.
2. calls wp() function. This function is available in /wp-includes/functions.php
3. includes /wp-includes/template-loader.php file.

wp()

• sets up WordPress Query.

/wp-load.php

• sets up ABSPATH constant.
• responsible for loading wp-config.php file.
• responsible for other necessary setup (installation process) if the wp-config.php file is not found (happens during manual WP installation process).

/wp-includes/template-loader.php

• This file loads the correct template (theme file) based on the visitor's url.

This file (/wp-load.php) does followings:

1. Defines the ABSPATH constant (absolute path to WordPress root).
2. Attempts to locate and load wp-config.php from the root directory, or one level above if not found.
3. If wp-config.php is missing, WordPress redirects the user to the installation process (/wp-admin/install.php).
4. During setup, if the server allows writing files, WordPress can create wp-config.php automatically. Otherwise, it instructs the user to create it manually.

This file (/wp-includes/template-loader.php) does the following:

Note: At this point, the WordPress environment is fully loaded. wp-load.php loads wp-config.php, which in turn loads wp-settings.php to set up constants, globals, and plugins.

1. Checks if themes are being used via wp_using_themes().
2. If themes are enabled, determines the correct template file to load based on the template hierarchy (e.g., index.php, single.php, page.php).
3. Loads the selected template, which outputs the page content.