private DownloadRequest getDownloadRequest(String requestId) throws HdfsApiException, IOException, InterruptedException {
    String fileName = getFileNameForRequestData(requestId);
    String json = HdfsUtil.readFile(getApi(), fileName);
    DownloadRequest request = gson.fromJson(json, DownloadRequest.class);

    deleteFileFromHdfs(fileName);
    return request;
  }
Generate link for concat
@param request download request
@return response wth request id
@see #concatByRequestId(String)
contrib/views/files/src/main/java/org/apache/ambari/view/filebrowser/DownloadService.java