private Response generateLink(DownloadRequest request) {
    try {
      String requestId = generateUniqueIdentifer(request);
      LOG.info("returning generated requestId : {}", requestId);
      JSONObject json = new JSONObject();
      json.put("requestId", requestId);
      return Response.ok(json).build();
    } catch (WebApplicationException ex) {
      throw ex;
    } catch (Exception ex) {
      throw new ServiceFormattedException(ex.getMessage(), ex);
    }
  }
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