Searching an article for a title is not a good idea, I would advise adding the "uri" field to a table with posts with unique values that would store the title of the article name in the transcription with replaced hyphens and spaces of characters
In the rules:
'post/<uri>' => 'item/view'
In the top:
$this->createUrl('item/view',array('uri'=>$model->uri))
In the action:
$model = Post::model()->find('uri = :uri', [':uri' => $uri]);
This way you will get the url / post / hello-world for an article titled "Hollo world !!!"
P.S. I can cheat, at once I apologize, for a long time I haven’t been Kolupa in Yii, I was busy with Yii2