public static function getInternalRemoteUrl(FileSync $file_sync)
 {
     KalturaLog::log("File Sync [{$file_sync->getId()}]");
     // LOG retrieval
     $dc = self::getDcById($file_sync->getDc());
     $file_sync_id = $file_sync->getId();
     $file_hash = md5($dc["secret"] . $file_sync_id);
     // will be verified on the other side to make sure not some attack or external invalid request
     $filename = 'f.' . $file_sync->getFileExt();
     $build_remote_url = $dc["url"] . "/index.php/extwidget/servefile/id/{$file_sync_id}/hash/{$file_hash}/f/{$filename}";
     // or something similar
     return $build_remote_url;
 }