In the previous blog we learnt about the basics of how to create a plugin in WordPress, this blog dives into the next steps of plugin creation.

Hooks: Actions and Filters

In WordPress, hooks are points in the WordPress execution flow where we can “hook into” the system to add or modify functionality. WordPress hooks allow you to interact with the code without modifying core files(as the saying goes never modify the WordPress Core), ensuring compatibility with future WordPress updates.

There are two main types of hooks:

1. Actions
2. Filters

Actions

An action hook is used to execute custom code at a specific point in the WordPress execution process.

Actions do not modify data, they are used to perform tasks, such as displaying content, sending emails, or logging information.

Example of action hook— suppose we want to add a message to the post body, we can tap into the functionality using the the_content hook.

function custom_message_action($content) {
    $custom_message = '<p>Thank you for reading my blog!</p>';
    return $content . $custom_message;
}
add_action('the_content', 'custom_message_action');

• the_content is an action hook that fires when the content of a post or page is displayed.
• custom_message_action is the function that will execute when the the_content hook is triggered.

When to use Actions:

We use action hooks when we need to perform an operation that doesn’t return data. Common use cases for action hooks include:

• Displaying content or elements in specific areas (e.g., footer, header)
• Registering settings
• Enqueuing scripts and styles
• Handling form submissions

Filters

A filter hook is used to modify data before it is sent to the browser or saved in the database.

Filters allow us to change the content or behavior of WordPress, such as altering post titles, content, or the structure of URLs.

Example of filter hook— suppose we want to change the title of a post, we can tap into the_title hook.

function modify_post_title($title) {
    if (is_single()) {
        $title = 'Featured: ' . $title;
    }
    return $title;
}
add_filter('the_title', 'modify_post_title');

• the_title is a filter hook that allows us to alter the title before it is displayed on the page.
• modify_post_title is the function that modifies the post title.

When to Use Filter:

We use filter hooks when we need to modify data before it’s displayed to users or saved to the database. Common use cases include:

• Modifying post content or titles
• Altering HTML output
• Changing form data before saving
• Customizing query arguments

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Understanding and utilizing hooks is fundamental to WordPress plugin development, as they allow us to extend and modify WordPress’s behavior in a clean, efficient manner.