public static function downloadSubtitle($subId)
 {
     $sub = Subtitle::find($subId);
     if ($sub === null || $sub->content === null) {
         return SubtitleDataService::downloadSubtitle($subId);
     } else {
         return $sub->content;
     }
 }
 public static function downloadSubtitle($subId)
 {
     $subtitleService = new SubtitleService();
     $loginResp = $subtitleService->login(env('OPENSUBTITLE_USERNAME'), env('OPENSUBTITLE_PASSWORD'), 'en', env('OPENSUBTITLE_USERAGENT'));
     if (!$loginResp) {
         return '';
     }
     $resp = $subtitleService->downloadSubtitle([$subId]);
     if ($resp !== '') {
         $sub = Subtitle::where('file_id', $subId)->first();
         $sub->content = $resp;
         $sub->save();
     }
     return $resp;
 }