wordpress-website-lifecycle/WordPress-internals.md

WordPress internals

WordPress core files in order of execution

• index.php
• wp-blog-header.php
• wp-load.php
• wp-config.php
• wp-settings.php
• wp-includes/version.php
• wp-includes/compat.php
• wp-includes/load.php
• wp-includes/class-wp-paused-extensions-storage.php
• wp-includes/class-wp-exception.php
• wp-includes/class-wp-fatal-error-handler.php
• wp-includes/class-wp-recovery-mode-cookie-service.php
• wp-includes/class-wp-recovery-mode-key-service.php
• wp-includes/class-wp-recovery-mode-link-service.php
• wp-includes/class-wp-recovery-mode-email-service.php
• wp-includes/class-wp-recovery-mode.php
• wp-includes/error-protection.php
• wp-includes/default-constants.php

List made with get_included_files().

WordPress Entry Points

context	entry point	function
front-end	wp-blog-header.php:12	!is_admin()
admin	GET request: wp-admin/admin.php:30	is_admin()
admin	POST request: wp-admin/admin-post.php:15	is_admin()
admin	upload: wp-admin/async-upload.php:16	@$_SERVER['SCRIPT_FILENAME'] === ABSPATH . 'wp-admin/async-upload.php'
AJAX call	wp-admin/admin-ajax.php:20	defined('DOING_AJAX') && DOING_AJAX
WordPress cron webserver/CLI	wp-cron.php:26	defined('DOING_CRON') && DOING_CRON / php_sapi_name() === 'cli'
XML-RPC protocol	xmlrpc.php:29	defined('XMLRPC_REQUEST') && XMLRPC_REQUEST

Frontend low priority

context	entry point	function
front-end	wp-comments-post.php:16	@$_SERVER['SCRIPT_FILENAME'] === ABSPATH . 'wp-comments-post.php'
front-end	wp-trackback.php:12	is_trackback()

Admin low priority

context	entry point	function
admin	wp-login.php:12	???
admin	wp-signup.php:4	???
admin	wp-mail.php:11	???

Only during core installation and upgrade

context	entry point	function
admin	wp-admin/install.php:36	defined('WP_INSTALLING') && WP_INSTALLING
admin	wp-admin/upgrade.php:18	defined('WP_INSTALLING') && WP_INSTALLING
admin	wp-activate.php:12	defined('WP_INSTALLING') && WP_INSTALLING
admin	wp-admin/maint/repair.php:10	defined('WP_REPAIRING') && WP_REPAIRING

Excluded from profiling

context	entry point	function
front-end	wp-links-opml.php:15	???
front-end	wp-includes/ms-files.php:12	???
front-end	wp-includes/js/tinymce/wp-mce-help.php:9	???
admin	wp-admin/install-helper.php:39	???
admin	wp-admin/moderation.php:10	???

Total: 21 entry points as of version 3.9.1

See WP trac #28364