Where is the right place to set a variable in a session in Yii?

Question

Yii

There is a site with subdomains. You need to define a subdomain, find out the region and show information for the corresponding region. Where is it better to check the subdomain and set the value to the session?
Now I have made a separate BaseController class, I check and remember the values ​​​​of it in init (), I inherit from it in all frontend controllers. It works, but I don't like that I'm inheriting from a new class.

Answer 1

Make a service if this data is needed in the future, otherwise the listener.
if component - sample config

return [
    'bootstrap' => [
        'mySubdomainComponent'
    ],
    'components' => [
        'mySubdomainComponent' => '\namespace\of\mySubdomainComponent'
    ]
];

// обработка данных в компоненте, метод init
...

// в дальнейшем можно получить компонент
\Yii::$app->get('mySubdomainComponent')

if listener - need to be added to bootstrap

$app = \Yii::$app;
$app->on($app::EVENT_BEFORE_REQUEST, ['myListener', 'method']);
// в листенере делаем нужную обработку
...