Hooks in WordPress allow plugins and themes to modify functionality by adding or removing actions and filters. There are two main types of hooks: action hooks, which execute functions at specific points, like when a post is published; and filter hooks, which modify data and content by filtering values before saving or output. Hooks provide an extensible system through functions like do_action(), apply_filters(), add_action(), add_filter(), and remove_action()/remove_filter().

2. ordPress
Hooks
(Actions, Filters)
Sanam Maharjan
(Nhuja Concepts)

3. What is hook?

4. The Proliferation of Hooks over Time

5. Action Hooks
• Used to stick a new function
• Add or remove elements
• Launches when specific events occur such as
publishing a post, changing themes, or displaying a
page of the admin panel.
• do_action( "hook_name" )
Filter Hooks
• Replaces or changes an existing function
• Change how elements are presented
• Launches to modify text of various types before
adding it to the database or sending it to the
browser screen.
• apply_filters( "hook_name", "what_to_filter" )

6. Different Functions for Hooks
Action Hooks Filter Hooks
 do_action()  apply_filters()
 add_action()  add_filter()
 remove_action()  remove_filter()
 has_action()  has_filter()
 do_action_ref_array()  current_filter()
 did_action()  merge_filters()
 remove_all_actions()  remove_all_filters()

7. Using Action Hooks
• do_action( 'hook_name‘, [$arg] );
• add_action (
'hook_name', 'your_function_name', [pri
ority], [accepted_args] );
• remove_action( 'hook_name‘, 'your_fun
ction_name', [$priority], [$accepted_arg
s]);

8. Using Filter Hooks
• apply_filters( 'hook_name’, $value, [$v
ar ...] );
• add_filter( 'hook_name’, ’function_to_
add’, [$priority], [$accepted_args] );
• remove_filter( 'hook_name’, ’function_
to_remove’, [$priority], [$accepted_args
] );

9. References
• http://codex.wordpress.org/Plugin_API
• http://adambrown.info/p/wp_hooks
• http://wpcandy.com/teaches/how-to-use-
wordpress-hooks

10. Thank you