Gudlyf's World

WordPress Plugin: Nofollow

// January 19th, 2005 // Techie

I’m not going to bother posting this as a downloadable plugin because it’s not worth it, but here’s a simple WordPress plugin you can use to add Google’s “nofollow” relative attribute to all links within comments:

< ?php
/*
Plugin Name: NoFollow
Plugin URI: http://www.gudlyf.com/archives/2005/01/19/wordpress-plugin-nofollow/
Description: Adds the "nofollow" relative attribute to links left in comments
(See http://www.google.com/googleblog/2005/01/preventing-comment-spam.html)
Version: 1.0
Author: Keith McDuffee
Author URI: http://www.gudlyf.com
*/

function nofollow($text) {

        $text = preg_replace('/<a /i','<a rel="nofollow" ',$text);
        return $text;
}

add_filter('comment_text', 'nofollow');
?>

I also recommend editing the comment_author_link() and comment_author_url_link() functions in the wp-includes/template-functions-comment.php file to read:

function comment_author_link() {
        global $comment;
        $url = apply_filters('comment_url', $comment->comment_author_url);
        $author = apply_filters('comment_author', $comment->comment_author);
        if (!$author) $author = 'Anonymous';

        if (empty($url)) :
                echo $author;
        else:
                echo "<a href='$url' rel='external' rel='nofollow'>$author</a>";
        endif;
}
function comment_author_url_link($linktext='', $before='', $after='') {
        global $comment;
        $url = apply_filters('comment_url', $comment->comment_author_url);

        if ((!empty($url)) && ($url != 'http://') && ($url != 'http://url')) {
        $display = ($linktext != '') ? $linktext : stripslashes($url);
                echo "$before<a href='$url' rel='external' rel='nofollow'>$display</a>$after";
        }
}