HttpClient in using statement causes Task cancelled

Question

I created a FileResult : IHttpActionResult webapi return type for my api calls. The FileResult downloads a file from another url and then returns the stream to

Answer 1

I had a similar issue with Task Canceled exceptions. If you try catching AggregateException or having a catch all Exception block underneath your WebException, you may well find that you catch it, with one exception with the entry stating "A task was canceled"

I did some investigation and found that the AggregateException is quite misleading as described in various threads;

Setting HttpClient to a too short timeout crashes process

How can I tell when HttpClient has timed out?

Bug in httpclientgetasync should throw webexception not taskcanceledexception

I ended up changing my code to set an explicit timeout (where asyncTimeoutInMins is read from the app.config file);

        string jsonResponse = string.Empty;
        try
        {
            using (HttpClient httpClient = new HttpClient())
            {
                httpClient.BaseAddress = new Uri(Properties.Settings.Default.MyWebService);
                httpClient.DefaultRequestHeaders.Accept.Clear();
                httpClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
                httpClient.Timeout = new TimeSpan(0, asyncTimeoutInMins, 0);

                HttpResponseMessage response;

                response = await httpClient.GetAsync("/myservice/resource");

                // Check the response StatusCode
                if (response.IsSuccessStatusCode)
                {
                    // Read the content of the response into a string
                    jsonResponse = await response.Content.ReadAsStringAsync();
                }
                else if (response.StatusCode == HttpStatusCode.Forbidden)
                {
                    jsonResponse = await response.Content.ReadAsStringAsync();

                    Logger.Instance.Warning(new HttpRequestException(string.Format("The response StatusCode was {0} - {1}", response.StatusCode.ToString(), jsonResponse)));

                    Environment.Exit((int)ExitCodes.Unauthorised);
                }
                else
                {
                    jsonResponse = await response.Content.ReadAsStringAsync();

                    Logger.Instance.Warning(new HttpRequestException(string.Format("The response StatusCode was {0} - {1}", response.StatusCode.ToString(), jsonResponse)));

                    Environment.Exit((int)ExitCodes.ApplicationError);
                }
           }

        }
        catch (HttpRequestException reqEx)
        {
            Logger.Instance.Error(reqEx);

            Console.WriteLine("HttpRequestException : {0}", reqEx.InnerException.Message);

            Environment.Exit((int)ExitCodes.ApplicationError);
        }
        catch (Exception ex)
        {
            Logger.Instance.Error(ex);

            throw;
        }

        return jsonResponse;