Using WordPress ‘duplicate_comment_id’ PHP filter

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The duplicate_comment_id WordPress PHP filter allows you to filter the ID of a duplicate comment found when creating a new comment.

Usage

add_filter('duplicate_comment_id', 'your_custom_function', 10, 2);
function your_custom_function($dupe_id, $commentdata) {
    // your custom code here
    return $dupe_id;
}

Parameters

  • $dupe_id (int): ID of the comment identified as a duplicate.
  • $commentdata (array): Data for the comment being created.

More information

See WordPress Developer Resources: duplicate_comment_id

Examples

Allow duplicate comments

Prevent WordPress from blocking duplicate comments by returning an empty value.

add_filter('duplicate_comment_id', 'allow_duplicate_comments', 10, 2);
function allow_duplicate_comments($dupe_id, $commentdata) {
    return '';
}

Allow duplicate comments from logged-in users

Allow logged-in users to post duplicate comments.

add_filter('duplicate_comment_id', 'allow_duplicate_comments_for_logged_in_users', 10, 2);
function allow_duplicate_comments_for_logged_in_users($dupe_id, $commentdata) {
    if (is_user_logged_in()) {
        return '';
    }
    return $dupe_id;
}

Block duplicate comments with custom error message

Display a custom error message when a duplicate comment is detected.

add_filter('duplicate_comment_id', 'custom_duplicate_comment_message', 10, 2);
function custom_duplicate_comment_message($dupe_id, $commentdata) {
    if ($dupe_id) {
        wp_die('Your comment appears to be a duplicate. Please try again.');
    }
    return $dupe_id;
}

Allow duplicate comments for specific post types

Allow duplicate comments for a custom post type, such as ‘product’.

add_filter('duplicate_comment_id', 'allow_duplicate_comments_for_products', 10, 2);
function allow_duplicate_comments_for_products($dupe_id, $commentdata) {
    $post_type = get_post_type($commentdata['comment_post_ID']);
    if ($post_type === 'product') {
        return '';
    }
    return $dupe_id;
}

Block duplicate comments within a specific time frame

Prevent users from posting duplicate comments within a 5-minute time frame.

add_filter('duplicate_comment_id', 'block_duplicate_comments_within_time_frame', 10, 2);
function block_duplicate_comments_within_time_frame($dupe_id, $commentdata) {
    if ($dupe_id) {
        $old_comment = get_comment($dupe_id);
        $time_diff = time() - strtotime($old_comment->comment_date);
        if ($time_diff < 300) { // 5 minutes in seconds
            wp_die('You cannot post a duplicate comment within 5 minutes. Please try again later.');
        }
    }
    return $dupe_id;
}