Session Exception

Hi, I checked user data, that stored in session.

What exception I need to generate, that would indicate to the user that his session is out of date and need to update?


if (Yii::app()->session['valid_systems']) {

    $systems = Yii::app()->session['valid_systems'];

} else {

    //Exception;

} 



Thanks!

you can throw a 500 with message saying you session has been expired please login again


throw new CHttpException(500, "Your session has been expired please login again.");