how to Json encode in yii2?

Question

Attempting to encode json and receive 400: Bad Request in yii2. I am trying to encode in Rest client but it is not working properly.

Answer 1

public function actionRegister()
{
    \Yii::$app->response->format = \yii\web\Response::FORMAT_JSON;
    $model = new TblUserRegistration();
    return $_POST['username'];
}