Using WordPress ‘pre_trash_post’ PHP filter

The ‘pre_trash_post’ WordPress PHP filter allows you to control whether a post should be trashed or not.

You can use this filter to add custom conditions before trashing a post.

Usage

apply_filters( 'pre_trash_post', $trash, $post );

Parameters

• $trash (bool|null): Whether to go forward with trashing the post.
• $post (WP_Post): The post object to be trashed.

Examples

Prevent trashing posts with specific tags

function prevent_trash_specific_tags( $trash, $post ) {
    // Check if the post has the tag "important"
    if ( has_tag( 'important', $post ) ) {
        return false;
    }

    return $trash;
}
add_filter( 'pre_trash_post', 'prevent_trash_specific_tags', 10, 2 );

In this example, we prevent posts with the “important” tag from being trashed. If a post has the “important” tag, the function returns false, and the post won’t be trashed.

Allow trashing only for draft posts

function trash_only_drafts( $trash, $post ) {
    // Check if the post is in draft status
    if ( 'draft' === $post->post_status ) {
        return true;
    }

    return false;
}
add_filter( 'pre_trash_post', 'trash_only_drafts', 10, 2 );

This example allows only draft posts to be trashed. If a post is not in draft status, it cannot be trashed.

Trash posts only by specific user role

function trash_posts_by_role( $trash, $post ) {
    $user = wp_get_current_user();

    // Check if the current user has the "editor" role
    if ( in_array( 'editor', $user->roles ) ) {
        return true;
    }

    return false;
}
add_filter( 'pre_trash_post', 'trash_posts_by_role', 10, 2 );

In this example, we allow only users with the “editor” role to trash posts. If the current user is not an editor, the post won’t be trashed.

Trash posts older than a specific date

function trash_old_posts( $trash, $post ) {
    $post_date = strtotime( $post->post_date );
    $cutoff_date = strtotime( '2023-01-01' );

    // Check if the post date is older than the cutoff date
    if ( $post_date < $cutoff_date ) {
        return true;
    }

    return false;
}
add_filter( 'pre_trash_post', 'trash_old_posts', 10, 2 );

This example checks if a post is older than a specific date (January 1, 2023). If the post is older than the cutoff date, it can be trashed.

Allow trashing only for posts with a minimum number of comments

function trash_posts_with_min_comments( $trash, $post ) {
    $comment_count = wp_count_comments( $post->ID )->approved;

    // Check if the post has at least 5 approved comments
    if ( $comment_count >= 5 ) {
        return true;
    }

    return false;
}
add_filter( 'pre_trash_post', 'trash_posts_with_min_comments', 10, 2 );

In this example, we allow trashing posts only if they have a minimum of 5 approved comments. If a post has fewer than 5 approved comments, it cannot be trashed.