This document discusses five important events in the WordPress lifecycle that developers should know about: init, request, pre_get_posts, template_redirect, and template_includes. It provides an overview of when each event fires and related actions and filters that can be used to modify WordPress behavior at different points. Hooks allow developers to attach custom functions to be executed at specific points, extending WordPress functionality.

1. Five Events In The Life Of
Every WordPress
Request You Should
Know
Josh Pollock

2. How Do We Get From This?

3. To This

4. Magic?

5. You're About To Get Super Powers

6. Let's Talk About Hooks
A hook is an event

7. Actions
Do Something At This Point
do_action( 'something' );
add_action( 'something', function() {
echo 'Doing Something';
});

8. Filters
Change Something At This Point
$something = apply_filters( 'something', 'something'
);
add_filter( 'something', function( $something) {
$something = 'something else';
return $something
});

9. You've Seen This Before
add_filter( 'the_content', function( $content ) {
$content .= '<a href="#">Share</a>';
return $content;
}
add_action( 'wp_head', function() {
echo "<script>alert( KHAAAAAAN!' ); </script>";
}

10. What Does WordPress Do?

12. Five Events You Should Know

13. init
/wp-includes/class-wp.php

14. Fires When WordPress Is Loaded
/wp-includes/class-wp.php

15. Before:
● muplugins_loaded
● plugins_loaded
● setup_theme
● after_setup_theme
After:
● wp_loaded
Related Actions

16. request
/wp-includes/class-wp.php

17. Modifies Query Vars Before Building WP_Query
/wp-includes/class-wp.php

18. Actions:
● parse_request
● send_headers
Filters:
● query_string
● wp_headers
Related Hooks

19. pre_get_posts
/wp-includes/query.php

20. Modifies WP_Query Arguments Before Querying
/wp-includes/query.php

21. Actions:
● start_loop
● end_loop
Filters:
● the_posts
● the_post
Related Hooks

22. template_redirect
/wp-includes/template.php

23. Before Choosing A Template
/wp-includes/template.php

24. Do something instead of the template
hierarchy.
WHY?

25. THEN THE TEMPLATE HIERARCHY HAPPENS

26. template_includes
/wp-includes/template.php

27. Change the template selected by the template
hierarchy
WHY?

31. CalderaWP.com
IngotHQ.com
@Josh412
JoshPress.net