HttpClient.SendAsync 即使发送的数据已处理，也会坐以待毙

Question

我不得不将应用程序从 ASP.Net Core 重写为 ASP.Net 4.6.1，在应用程序的核心版本中，我将 Json 数据发送到 BugZilla 进行处理，它工作正常。它发送数据并相当快地得到响应。应用程序 4.6.1 版本中的相同代码位于并挂在发送命令上。我可以进入 BugZilla 并看到它获取了数据并生成了错误，但即使在 15 分钟后应用程序也没有进展。我是 Task 和通过 Json 发送数据的新手，所以我不确定为什么运行会遇到这个问题。不会返回任何错误，并且在调试模式下我可以单步执行所有操作并知道它正在处理并在 SendAsync 行等待。我做错了什么在 4.6.1 中打破了这个？

private static async Task<int> LogToBugZilla(string Component, Exception ex)
{
    var ErrorSummary = "Auto Error Logging: " + ex.Message + " " + ex.InnerException.Message;

    var BugData = new Dictionary<string, string>
    {
        { "Bugzilla_api_key", ConfigurationManager.AppSettings["BugZillaAPIKey"] },
        { "product", "Job Site" },
        { "component", Component },
        { "version", ConfigurationManager.AppSettings["AppVersion"] },
        { "summary", ErrorSummary },
        { "op_sys", "All" },
        { "platform", "Other" },
        { "description", ex.StackTrace + ex.InnerException.StackTrace }
    };

    string Json = JsonConvert.SerializeObject(BugData, Formatting.None);
    var Client = new HttpClient();
    var Request = new HttpRequestMessage(HttpMethod.Post, "http://bugzilla/rest/bug");
    Request.Content = new StringContent(Json, Encoding.UTF8, "application/json");
    Request.Headers.Add("Accept", "application/json");
    var Response = await Client.SendAsync(Request);
    var JsonResults = await Response.Content.ReadAsStringAsync();

    if (Response.StatusCode == HttpStatusCode.OK)
    {
        var Results = JsonConvert.DeserializeObject<Dictionary<string, int>>(JsonResults);
        return Results["id"];
    }
    else
    {
        return -1;
    }
}

编辑：

public static string ProcessError(Exception ex, string OriginatingController)
{
    var Component = GetComponent(OriginatingController);
    string UserErrorMessage = "";

    switch (ex.GetType().ToString())
    {
        case "System.Data.DataException":
            LogToITSupport("Database Connection");
            UserErrorMessage = @"An error has accrued connecting to the database. <a href=""mailto:"">IT Support</a> has been notified  of this error. Please try your request again later, thank you.";
            break;

        default:
            var BugID = LogToBugZilla(Component, ex).Result;
            UserErrorMessage = @"An error has accrued processing your request and a log of this error has been made on the <a href=""http://bugzilla/show_bug.cgi?id=" + BugID + "\">Internal Tools BugZilla system</a> with an ID of " + BugID + ". Please try your request again later, thank you.";
            break;
    }

    return UserErrorMessage;
}

重申一下，应用程序在代码 var Response = await Client.SendAsync(Request);

上挂起

编辑 2：

控制器代码：

public ActionResult About()
{
    try
    {
        using (var db = new JobSightDbContext())
        {
            var model = db.ReleaseVersions
                            .OrderByDescending(rv => rv.DateReleased)
                            .Select(rv => new ReleaseNotesVM()
                            {
                                ID = rv.ID,
                                CurrentVersion = string.Concat(rv.Major, ".", rv.Minor, ".", rv.Patch),
                                CurrentVersionReleaseDate = rv.DateReleased,
                                ReleaseNotes = rv.ReleaseNotes.Select(rn => rn.Note).ToList()
                            }).First();

            //model.VersionList = db.ReleaseVersions
            //                      .OrderByDescending(rv => rv.DateReleased)
            //                      .Select(rv => new SelectListItem()
            //                      {
            //                          Value = rv.ID.ToString(),
            //                          Text = string.Concat(rv.Major, '.', rv.Minor, '.', rv.Patch)
            //                      }).ToList();

            return View(model);
        }
    }
    catch (System.Data.DataException ex)
    {
        ViewBag.ErrorMessage = EHALM.ProcessError(ex, RouteData.Values["controller"].ToString());
        return View("Dashboard");
    }
}

Answer 1

这是我用来发送 HTTP 请求的一些通用代码。工作正常，唯一不同的是我使用的是 .Net 4.5。对于 4.6

应该不是问题

private async Task<HttpUtilResponse> DoRequest(List<RequestResponseHeader> headers, HttpMethod method, string url, string requestData) {
     HttpUtilResponse response = new HttpUtilResponse();
     string responseData = string.Empty;
     using (System.Net.Http.HttpClient client = new System.Net.Http.HttpClient()) {          
        using (HttpRequestMessage request = new HttpRequestMessage(method, url)) {
           if (headers != null) {
              headers.ForEach(h => request.Headers.Add(h.Name, h.Value));
           }               
           if (!string.IsNullOrEmpty(requestData)) {
              if (AppConfig.LogRequestContent) {
                 LOG.Debug(requestData);
              }
              request.Content = new StringContent(requestData, Encoding.UTF8, JSON_CONTENT);                  
           }
           using (HttpResponseMessage msg = await client.SendAsync(request, CancelToken.Token)) {
              response.StatusCode = msg.StatusCode;
              response.ReasonPhrase = msg.ReasonPhrase;
              using (HttpContent content = msg.Content) {
                 response.ResponseText = await content.ReadAsStringAsync();
              }
           }
        }
     }
     return response;
  }

Answer 2

我要在这里继续跛行并说你在你的调用堆栈中像这样使用 LogToBugZilla:

public void DoStuff()
{
    var result = LogToBugZilla("Component", exception).Result;
}

这实际上会使您的代码陷入僵局，这也是 you shouldn't block on async code 的原因。您需要将代码 "async all the way" 放到调用堆栈的顶部。这意味着将 DoStuff 转换为 DoStuffAsync 并像这样调用它：

public async Task DoStuffAsync()
{
    var result = await LogToBugZillaAsync("Component", exception);
    // Do stuff with result
}

请注意，我根据推荐的编码约定将 "async" 后缀添加到 LogToBugZilla。

编辑：

鉴于您提供了调用方法，它应该如下所示：

public static async Task<string> ProcessErrorAsync(
            Exception ex, string OriginatingController)
{
    var Component = GetComponent(OriginatingController);
    string UserErrorMessage = "";

    switch (ex.GetType().ToString())
    {
        case "System.Data.DataException":
            LogToITSupport("Database Connection");
            UserErrorMessage = @"An error has accrued connecting to the 
            database. <a href=""mailto:"">IT Support</a> has been notified
            of this error. Please try your request again later, thank you.";
            break;

        default:
            var bugId = await LogToBugZillaAsync(Component, ex);
            UserErrorMessage = @"An error has accrued processing your request 
            and a log of this error has been made 
            on the <a href=""http://bugzilla/show_bug.cgi?id=" + BugID +
            "\">Internal Tools BugZilla system</a> 
            with an ID of " + bugId + ". Please try your request again later, thank you.";
            break;
    }
    return UserErrorMessage;
}

现在记住这需要一直向上。这意味着每个调用 ProcessErrorAsync 的方法本身都应该是 async 和 return 一个 Task 或 Task<T>.

HttpClient.SendAsync 即使发送的数据已处理，也会坐以待毙

HttpClient.SendAsync sits and never progress, even though the data sent is processed

c#

asp.net-mvc

asynchronous

async-await

.net-4.6