/**
  * Advert file uploading.
  */
 public function actionUpload()
 {
     $request = Yii::$app->request;
     $owner = $request->post('owner');
     $ownerId = $request->post('ownerId');
     if (!$owner || !$ownerId) {
         throw new BadRequestHttpException('Ошибка загрузки!');
     }
     if (!($model = File::saveUploadedFile()) || !$model->attachOwner($ownerId, $owner, 'files')) {
         throw new HttpException(500, 'Ошибка загрузки!');
     }
     if ($request->isAjax) {
         return $this->renderPartial('//advert/dropzone/_file', compact('model'));
     }
     return $this->redirect($request->referrer);
 }