add_action and add_filter in Wordpress - Mini Project: Build & Apply

Using add_action and add_filter in WordPress

📖 Scenario: You are building a simple WordPress plugin to customize how your site works. You want to add a message to the footer and change the title of posts before they show on the site.

🎯 Goal: Build a WordPress plugin that uses add_action to add a footer message and add_filter to modify post titles.

📋 What You'll Learn

Create a function called custom_footer_message that echoes a footer message

Use add_action to hook custom_footer_message to the wp_footer action

Create a function called modify_post_title that adds ' - Custom' to the post title

Use add_filter to hook modify_post_title to the the_title filter

💡 Why This Matters

🌍 Real World

WordPress developers use add_action and add_filter to customize themes and plugins safely and flexibly.

💼 Career

Understanding hooks is essential for WordPress plugin and theme development jobs.

1

Create the footer message function

Create a function called custom_footer_message that echoes the text 'Thank you for visiting!'.

Wordpress

<?php
// Plugin main file

// Your code here

Need a hint?

Use the function keyword to create custom_footer_message. Inside, use echo to show the message.

2

Hook the footer message function to wp_footer

Use add_action to hook the custom_footer_message function to the wp_footer action.

Wordpress

<?php
// Plugin main file

function custom_footer_message() {
    echo 'Thank you for visiting!';
}

// Your code here

Need a hint?

Call add_action with the first argument as 'wp_footer' and the second as 'custom_footer_message'.

3

Create the post title modification function

Create a function called modify_post_title that takes one parameter $title and returns the title with ' - Custom' added at the end.

Wordpress

<?php
// Plugin main file

function custom_footer_message() {
    echo 'Thank you for visiting!';
}

add_action('wp_footer', 'custom_footer_message');

// Your code here

Need a hint?

Define modify_post_title with $title as input. Use return to add ' - Custom' to the title.

4

Hook the post title modification function to the_title filter

Use add_filter to hook the modify_post_title function to the the_title filter.

Wordpress

<?php
// Plugin main file

function custom_footer_message() {
    echo 'Thank you for visiting!';
}

add_action('wp_footer', 'custom_footer_message');

function modify_post_title($title) {
    return $title . ' - Custom';
}

// Your code here

Need a hint?

Call add_filter with 'the_title' as the first argument and 'modify_post_title' as the second.