The document describes hooking in WordPress, focusing on actions and filters that allow modification of function behavior during execution. It provides PHP code examples for the implementation of hooks and describes the roles of source modification and runtime modification. Additional resources and references for further understanding of WordPress hooks are also included.

1. Hooking with
WordPress

2. What is Hooking?

3. Example:

4. Example:

5. Methods
- Source Modification
- Modify behavior before the application starts.
- i.e, patch created by reverse engineering the
application
- Runtime Modification
- Modify behavior while the application is running.

6. Core php example

7. Hooks
<?php
function do_action( $function_name, $args ) {
if ( function_exists( $function_name ) {
call_user_func( $function_name,
$args );
}
}
?>
<?php
function apply_filter( $function_name, $args ) {
if ( function_exists( $function_name ) {
return call_user_func( $function_name, $args );
}
return $args;
}
?>

8. WordPress CMS

9. WordPress Hooks
- Actions
- Execute extra code in between code execution.
- Filters
- Change/Update behaviour of existing code.

10. WP Action
<?php
do_action( ‘init’);
<?php
function wporg_custom() {
// do something
}
add_action('init', 'wporg_custom');
add_action ( 'hook_name', 'your_function_name', [priority], [accepted_args] );
Examples:

11. WP Filters
<?php
$title = apply_filter( ‘the_title’, $title );
<?php
function wporg_filter_title($title) {
return 'The ' . $title . ' was filtered';
}
add_filter('the_title', 'wporg_filter_title');
add_filter ( 'hook_name', 'your_filter', [priority], [accepted_args] );
Examples:

12. Hooking: https://en.wikipedia.org/wiki/Hooking
WP Hooks: https://developer.wordpress.org/plugins/hooks/
WP Actions: https://developer.wordpress.org/plugins/hooks/actions/
WP Filter: https://developer.wordpress.org/plugins/hooks/filters/
References

13. WP Reference Code
https://core.trac.wordpress.org/browser/trunk/src/wp-
includes/plugin.php#L428
https://core.trac.wordpress.org/browser/trunk/src/wp-
includes/class-wp-hook.php

14. Got Questions?
Rahul Prajapati
@rahulsprajapati
rahul.prajapati@live.in