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Understanding WordPress Hooks: Action and Filter
In this blog, we’ll explain:
- What hooks are
- Types of hooks: Action Hooks and Filter Hooks
- How to use them with PHP examples
What are Hooks in WordPress?
Hooks are spots in WordPress core where you can “hook into” and run your custom code without modifying core files.
They let developers add, modify, or override WordPress functionality safely.
Types of Hooks
WordPress has two main types of hooks:
1️⃣ Action Hooks
These allow you to add or execute code at specific points in WordPress, such as when a post is published, or just before the footer loads.
Syntax: add_action( 'hook_name', 'your_function_name' );
function add_custom_message_after_post( $content ) {
if ( is_single() ) {
$content .= ‘<p>Thank you for reading!</p>’;
}
return $content;
}
add_filter( ‘the_content’, ‘add_custom_message_after_post’ );
Here, we’re technically using a filter hook on the_content, but actions are similar — the difference is that actions don’t modify data, just execute code.
Example of action:
function run_after_theme_setup() {
// your code here
}
add_action( ‘after_setup_theme’, ‘run_after_theme_setup’ );
2️⃣ Filter Hooks
These let you modify data before it’s output to the browser or saved to the database.
Syntax: add_filter( 'hook_name', 'your_function_name' );
function modify_post_title( $title ) {
return ‘🔥 ‘ . $title;
}
add_filter( ‘the_title’, ‘modify_post_title’ );
Here, every post title gets a 🔥 prefix using the the_title filter hook.
Best Practices
To avoid conflicts, follow these best practices:
- Always prefix your functions to avoid conflicts.
- Use remove_action() or remove_filter() if needed.
- Read the WordPress Codex for a full list of hooks.
Conclusion
Hooks are the backbone of WordPress customization. Action Hooks let you run code at specific events, while Filter Hooks let you modify content/data. Mastering these will make you a better WordPress developer!
