public function actionNames()
 {
     $ids = $this->getQuery('campaignIds');
     if (empty($ids)) {
         return [];
     }
     $ids = explode(',', $ids);
     $campaignIds = MongodbUtil::toMongoIdList($ids);
     $campaigns = Campaign::getByIds($campaignIds);
     $names = [];
     foreach ($campaigns as $campaign) {
         $names[] = $campaign->name;
     }
     return $names;
 }