Common filter hooks in Wordpress - Mini Project: Build & Apply

Using Common Filter Hooks in WordPress

📖 Scenario: You are customizing a WordPress site to change how some content appears without editing core files. WordPress filter hooks let you modify data before it shows on the site.

🎯 Goal: Learn how to use common WordPress filter hooks by writing code that changes the site title, modifies post content, and adjusts excerpt length.

📋 What You'll Learn

Create a function to change the site title using the bloginfo filter

Create a function to add text at the end of post content using the the_content filter

Create a function to set the excerpt length to 20 words using the excerpt_length filter

Add the filter hooks with add_filter to connect your functions

💡 Why This Matters

🌍 Real World

WordPress developers often use filter hooks to customize site behavior and appearance without changing core files, making updates safer and easier.

💼 Career

Knowing how to use WordPress filter hooks is essential for WordPress theme and plugin developers to create flexible and maintainable customizations.

1

Create a function to change the site title

Write a function called custom_site_title that takes one parameter $title and returns the string 'My Custom Site'. This will replace the default site title.

Wordpress

# Your code here

Need a hint?

Functions in PHP start with function keyword. The function must return the new title string.

2

Add the filter hook for the site title

Use add_filter to connect the custom_site_title function to the bloginfo filter hook. Write the line: add_filter('bloginfo', 'custom_site_title');

Wordpress

<?php
function custom_site_title($title) {
    return 'My Custom Site';
}

# Your code here

Need a hint?

The add_filter function connects your function to the WordPress filter hook.

3

Create a function to add text at the end of post content

Write a function called append_custom_text that takes one parameter $content and returns the original content plus the string '

Thank you for reading!

' appended at the end.

Wordpress

<?php
function custom_site_title($title) {
    return 'My Custom Site';
}

add_filter('bloginfo', 'custom_site_title');

# Your code here

Need a hint?

Use the dot . operator to join strings in PHP.

4

Add filter hooks for post content and excerpt length

Use add_filter to connect append_custom_text to the the_content filter, and add another function custom_excerpt_length that returns 20 for excerpt length. Connect it to the excerpt_length filter with add_filter('excerpt_length', 'custom_excerpt_length');

Wordpress

Thank you for reading!';
}

# Your code here

Need a hint?

Remember to define the function custom_excerpt_length that returns 20, then add the filter hook.