一个不错的WordPress评论算术题验证码插件

if(!class_exists('comment_capatcha')) {
    class comment_capatcha {
        function __construct() {
            add_action('comment_form', array(& $this, 'print_capatcha'));
            add_filter('preprocess_comment', array(& $this, 'preprocess_comment'));
        }
        function print_capatcha() {
            if(!is_user_logged_in()) {
                global $post;
                session_start();
                $rand_1 = mt_rand(1,20);
                $rand_2 = mt_rand(1,20);
                $_SESSION['capatcha_'.$post->ID] = $rand_1 + $rand_2;

                $str  = '

                echo $str;-
            }
        }
        function preprocess_comment($commentdata) {
            if(!is_user_logged_in()) {
                session_start();
                $post_id = isset($_POST['comment_post_ID']) ? $_POST['comment_post_ID'] : 0;
                if(!$post_id){
                    wp_die('警告：数据来源非法！！');
                }
                $capatcha = $_SESSION['capatcha_'.$post_id];
                if($capatcha != $_POST['capatcha']){
                    wp_die( __('警告：你智商有问题，不允许评论，请返回重新计算。') );
                }
                unset($_SESSION['capatcha_'.$post_id]);
            }
            return $commentdata;
        }
    }

}

if( !isset($comment_capatcha) ) {
    $comment_capatcha =& new comment_capatcha();
}