public HttpResponseMessage IsUpdateAvailable(IsUpdateAvailableRequestModel requestModel)
        {

            requestModel = new IsUpdateAvailableRequestModel() {

                InstallationGuid = requestModel.InstallationGuid,
                LastDateModified = requestModel.LastDateModified

                //InstallationGuid = Guid.Parse("90b2044c-ae0a-46f3-9260-acf3a058294a"),
                //LastDateModified = DateTime.Now
            };


            if (!ModelState.IsValid)
            {
                return Request.CreateErrorResponse(HttpStatusCode.BadRequest, "Invalid Download Request");
            }

            UpdateActions updateActions = new UpdateActions();
            IsUpdateAvailableResponseModel responseModel = updateActions.IsUpdateAvailable(requestModel);

            if (responseModel.Error != null)
            {
                return Request.CreateErrorResponse(HttpStatusCode.OK, responseModel.Error);
            }

            return Request.CreateResponse(HttpStatusCode.OK, responseModel, "application/json");
        }
        public HttpResponseMessage UpdateFromServer()
        {

            if (!ModelState.IsValid)
            {
                return Request.CreateErrorResponse(HttpStatusCode.BadRequest, "Invalid Download Request");
            }

            UpdateActions updateActions = new UpdateActions();
            DataResponseModel responseModel = updateActions.UpdateFromServer();

            if (responseModel.Error != null)
            {
                return Request.CreateErrorResponse(HttpStatusCode.OK, responseModel.Error);
            }

            return Request.CreateResponse(HttpStatusCode.OK, responseModel, "application/json");
        }