Why need in lastModified - $params ? And how can I get a variable from the GET request?

Yii 2.0 General Discussions
1

Why need in lastModified - $params ? $params returns NULL even when i send GET request with params. And how can I get a variable from the GET request in anonymous function for last Modified?

I can do so (get params form GET request) - How i can params form GET request in YII2?:

$a2 = $_GET[‘number’];


public function behaviors()

{

    return [

        [

            'class' => 'yii\filters\HttpCache',

            'only' => ['index'],

            'lastModified' => function ($action, $params) {

                $q = new \yii\db\Query();

                return $q->from('post')->max('updated_at');

            },

        ],

    ];

}

Yii version 2.0. ? Yes, This is Yii version 2.0.8.

PHP version 5.6

Operating system windows 8 and Linux last