How to use pre_trash_post filter in WordPress

pre_trash_post filter

Filters whether a post trashing should take place.

To use the pre_trash_post filter, first you have to register it using add_filter. You can write this code into functions.php of your activated theme or in a custom WordPress Plugin.

We at WePlugins always prefer to create a custom WordPress Plugin while using hooks so nothing breaks when you update your WordPress Theme in the future.

In the below live example, we have defined a function weplugins_modify_pre_trash_post_defaults which takes 2 parameters and we registered using add_filter. The first parameter pre_trash_post is the name of the hook, the second parameter weplugins_modify_pre_trash_post_defaults is the name of the function which needs to be called, the third parameter is the priority of calling the hook if the same hook is used multiple times, and the last parameter is the number of arguments (if any) to be passed in the registered function.

Sometimes, you have to remove a registered hook, so you can use remove_filter to remove the pre_trash_post filter.

Parameters

Below are the 2 parameters required to use this hook:

• $trash: (bool|null) Whether to go forward with trashing.
• $post: (WP_Post) Post object.

Live Example

apply_filters( 'pre_trash_post', bool|null $trash, WP_Post $post )

Below is an example of how you can use this hook.

Example 1: Basic Usage

This example shows the basic usage of the pre_trash_post filter.

    function weplugins_modify_pre_trash_post_defaults($trash, $post) { 
        // Update the $trash variable according to your website requirements and return this variable. 
        // You can modify the $trash variable conditionally too if you want.
        return $trash; 
    }
    // Add the filter
    add_filter( "pre_trash_post", "weplugins_modify_pre_trash_post_defaults", 10, 2 );
    

Example 2: Conditional Trashing

This example demonstrates how to conditionally trash a post based on custom criteria.

    function weplugins_conditional_pre_trash_post($trash, $post) { 
        // Conditionally set $trash to false if the post title contains 'Do Not Trash'
        if (strpos($post->post_title, 'Do Not Trash') !== false) {
            $trash = false;
        }
        return $trash; 
    }
    // Add the filter
    add_filter( "pre_trash_post", "weplugins_conditional_pre_trash_post", 10, 2 );
    

Example 3: Logging Trashed Posts

This example logs the post ID of each trashed post for record-keeping purposes.

    function weplugins_log_trashed_posts($trash, $post) { 
        if ($trash) {
            error_log('Post ID ' . $post->ID . ' was trashed.');
        }
        return $trash; 
    }
    // Add the filter
    add_filter( "pre_trash_post", "weplugins_log_trashed_posts", 10, 2 );
    

To remove a hook callback, use the example below.

remove_filter( "pre_trash_post", "weplugins_modify_pre_trash_post_defaults", 10, 2 );

Please make sure to provide the same callback function name, priority, and number of arguments while removing the hook callback.

Contact Us

If you need any customization or assistance with this hook, feel free to contact us.