Flash Data

Flash data is a kind of session data, which possesses the following features.

Set in one request.
Only available during the next request.
Automatically deleted afterwards.

It is mainly used to deliver messages to the end users that is delivered only once such as confirmation messages sent after the login.

Example

Step 1 Create an action ationFlashData in the SiteController.php file.

 public function actionFlashData() 
    { 
   $session = Yii::$app->session; 
   // set a flash message named as "welcome" 
   $session->setFlash('welcome', 'Successfully Logged In!'); 
   return $this->render('flashdata'); 
    } 

Step 2 Create a view file flashdata.php in the views/site folder.

<?php 
   use yii\bootstrap\Alert; 
   echo Alert::widget([ 
      'options' => ['class' => 'alert-info'], 
      'body' => Yii::$app->session->getFlash('welcome'), 
   ]); 
?>

Step 3 Run it on the browser with the URL,