c# – 异步webrequest超时=>崩溃IIS

发布时间：2020-12-15 04:00:45 所属栏目：百科来源：网络整理

导读：我有一个网络应用程序,从外部服务获取数据.请求本身就像下面的代码一样 – 就我所见,非常简单.创建一个请求,异步激活它并让回调处理响应.在我的开发环境中正常工作. public static void MakeRequest(Uri uri,ActionStream responseCallback) { WebRequest re

我有一个网络应用程序,从外部服务获取数据.请求本身就像下面的代码一样 – 就我所见,非常简单.创建一个请求,异步激活它并让回调处理响应.在我的开发环境中正常工作.

public static void MakeRequest(Uri uri,Action<Stream> responseCallback)
        {
            WebRequest request = WebRequest.Create(uri);
            request.Proxy = null;
            request.Timeout = 8000;
            try
            {
                Task.Factory.FromAsync<WebResponse>(request.BeginGetResponse,request.EndGetResponse,null)
                    .ContinueWith(task =>
                                      {
                                          WebResponse response = task.Result;
                                          Stream responseStream = response.GetResponseStream();
                                          responseCallback(response.GetResponseStream());
                                          responseStream.Close();
                                          response.Close();
                                      });
            } catch (Exception ex)
            {
                _log.Error("MakeRequest to " + uri + " went wrong.",ex);
            }
        }

但是,出于我之外的原因,外部测试环境和生产环境可能无法到达目标URL.很好,我想 – 请求超时不会真的伤害任何人.但是,似乎每次此请求超时,ASP.NET崩溃并重新启动IIS.事件日志向我展示了这个堆栈跟踪：

StackTrace:    at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
   at System.Threading.Tasks.Task`1.get_Result()
   at MyApp.AsyncWebClient.<>c__DisplayClass2.<MakeRequest>b__0(Task`1 task)
   at System.Threading.Tasks.Task`1.<>c__DisplayClass17.<ContinueWith>b__16(Object obj)
   at System.Threading.Tasks.Task.InnerInvoke()
   at System.Threading.Tasks.Task.Execute()

InnerException: System.Net.WebException

Message: Unable to connect to the remote server

StackTrace:    at System.Net.HttpWebRequest.EndGetResponse(IAsyncResult asyncResult)
   at System.Threading.Tasks.TaskFactory`1.FromAsyncCoreLogic(IAsyncResult iar,Func`2 endMethod,TaskCompletionSource`1 tcs)

InnerException: System.Net.Sockets.SocketException

Message: A connection attempt failed because the connected party did not properly respond after a period of time,or established connection failed because connected host has failed to respond

StackTrace:    at System.Net.Sockets.Socket.EndConnect(IAsyncResult asyncResult)
   at System.Net.ServicePoint.ConnectSocketInternal(Boolean connectFailure,Socket s4,Socket s6,Socket& socket,IPAddress& address,ConnectSocketState state,IAsyncResult asyncResult,Int32 timeout,Exception& exception)

..所以这一切归结为一个SocketException,在我看来.然后(在同一秒内)记录另一个事件(我猜是相关的)：

Exception Info: System.AggregateException
Stack:
   at System.Threading.Tasks.TaskExceptionHolder.Finalize()

这有点超出我的范围,因为我不是异步代码和线程的掌握,但是来自Web请求的超时导致IIS崩溃似乎非常奇怪.我重新实现了MakeRequest来同步执行请求,效果很好.该请求在这些环境中仍然超时,但没有造成任何损害,应用程序继续快乐地运行.

所以我有点解决了我的问题,但为什么会这样呢？任何人都可以开导我吗？

（编辑：李大同）

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c# – 异步webrequest超时=&gt;崩溃IIS

c# – 异步webrequest超时=>崩溃IIS