c# - 系统.ServiceModel.CommunicationException : The underlying connection was closed

Question

我正在从一个 wcf 网络服务中检索数据，当数据超过 20 万条记录时，我得到一个异常，如下所示:

System.ServiceModel.CommunicationException: The underlying connection was closed: A connection that was expected to be kept alive was closed by the server. ---> System.Net.WebException: The underlying connection was closed: A connection that was expected to be kept alive was closed by the server. ---> System.IO.IOException: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host. ---> System.Net.Sockets.SocketException: An existing connection was forcibly closed by the remote host
at System.Net.Sockets.Socket.Receive(Byte[] buffer, Int32 offset, Int32 size, SocketFlags socketFlags)
at System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size)
--- End of inner exception stack trace ---
at System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size)
at System.Net.PooledStream.Read(Byte[] buffer, Int32 offset, Int32 size)
at System.Net.Connection.SyncRead(HttpWebRequest request, Boolean userRetrievedStream, Boolean probeRead)
--- End of inner exception stack trace ---
at System.Net.HttpWebRequest.GetResponse()
at System.ServiceModel.Channels.HttpChannelFactory`1.HttpRequestChannel.HttpChannelRequest.WaitForReply(TimeSpan timeout)
--- End of inner exception stack trace ---

Server stack trace: 
at System.ServiceModel.Channels.HttpChannelUtilities.ProcessGetResponseWebException(WebException webException, HttpWebRequest request, HttpAbortReason abortReason)
at System.ServiceModel.Channels.HttpChannelFactory`1.HttpRequestChannel.HttpChannelRequest.WaitForReply(TimeSpan timeout)
at System.ServiceModel.Channels.RequestChannel.Request(Message message, TimeSpan timeout)
at System.ServiceModel.Dispatcher.RequestChannelBinder.Request(Message message, TimeSpan timeout)
at System.ServiceModel.Channels.ServiceChannel.Call(String action, Boolean oneway, ProxyOperationRuntime operation, Object[] ins, Object[] outs, TimeSpan timeout)
at System.ServiceModel.Channels.ServiceChannelProxy.InvokeService(IMethodCallMessage methodCall, ProxyOperationRuntime operation)
at System.ServiceModel.Channels.ServiceChannelProxy.Invoke(IMessage message)

我的 web.config 看起来像这样:

<basicHttpBinding>
  <binding name="BasicHttpBinding_IService" closeTimeout="00:01:00" openTimeout="00:01:00" receiveTimeout="00:10:00" sendTimeout="00:01:00"
             maxBufferSize="2147483647" maxBufferPoolSize="2147483647" maxReceivedMessageSize="2147483647"
             allowCookies="false" bypassProxyOnLocal="false" hostNameComparisonMode="StrongWildcard"
             messageEncoding="Text" textEncoding="utf-8" transferMode="StreamedResponse" useDefaultWebProxy="true">
    <readerQuotas maxDepth="32" maxStringContentLength="2147483647" maxArrayLength="2147483647"
                  maxBytesPerRead="2147483647" maxNameTableCharCount="2147483647" />
    <security mode="None">
      <transport clientCredentialType="None" proxyCredentialType="None" realm="" />
      <message clientCredentialType="UserName" algorithmSuite="Default" />
    </security>
  </binding>
  <binding maxReceivedMessageSize="2147483647" allowCookies="true">
    <readerQuotas maxDepth="32" maxStringContentLength="2147483647" maxArrayLength="2147483647" maxBytesPerRead="2147483647"
maxNameTableCharCount="2147483647" />
  </binding>
</basicHttpBinding>

我确定我的 Web 服务正在从数据库中检索数据。但无法从我发起调用的地方转移到我的网站。在此先感谢您的帮助。

Answer 1

我最近在 .Net 4.0 网络应用程序中的 Wcf 服务遇到了同样的问题。我增加了 maxItemsInObjectGraph 值，服务器不再抛出异常。文档 here说默认最大值是 Int32.MaxValue 但我认为这是不正确的，最大值是 65535。

   <serviceBehaviors>
    <behavior name="ServiceBehaviour">
      <dataContractSerializer maxItemsInObjectGraph="6553500"/>
      <serviceMetadata httpGetEnabled="true" />
      <serviceDebug includeExceptionDetailInFaults="true" />
    </behavior>
  </serviceBehaviors>

您可以做的另一件事是启用跟踪。这是我在 web.config 中的示例:

<system.diagnostics>
  <sources>
    <source name="System.ServiceModel"
            switchValue="Information, ActivityTracing"
            propagateActivity="true">
      <listeners>
        <add name="traceListener"
            type="System.Diagnostics.XmlWriterTraceListener"
            initializeData= "c:\temp\log\Traces.svclog" />
      </listeners>
    </source>
  </sources>
</system.diagnostics>

如果您双击 Traces.svclog，Windows 应该会打开 Microsoft Service Trace Viewer。

如果您使用 Microsoft WCF 测试客户端测试您的服务，请确保更改默认客户端配置以匹配服务器设置(这包括客户端端点行为)以确保客户端可以接收来自服务器的响应。