System.ServiceModel.CommunicationException：底层连接已关闭

Question

我正在从 WCF Web 服务检索数据，当数据超过 20 万条记录时，我收到如下异常：

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>

我确信我的网络服务正在从数据库检索数据。但无法从我发起呼叫的地方转移到我的网站。预先感谢您的帮助。

Answer 1

我最近在 .Net 4.0 Web 应用程序中的 Wcf 服务中遇到了同样的问题。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>

如果双击 Traces.svclog，Windows 应打开 Microsoft 服务跟踪查看器。

如果您使用 Microsoft WCF 测试客户端测试服务，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。

Answer 2

使您的客户端 basicHttpBinding 与服务器绑定相同。这是一种非常常见的错误，仅更改一个绑定而不是服务器和客户端绑定。

如果这不起作用，您可以启用 wcf 跟踪： wcf 跟踪

这将使您更深入地了解根本问题是什么。

Answer 3

我们的对象图中有一个正在返回的循环。我知道这可能不是您的问题，但我将其添加到此处以防其他人遇到同样的问题。我们启用了 includeExceptionDetailInFaults，但没有在任何客户端（我们的应用程序或 WCF 测试客户端）中收到错误。幸运的是它出现在服务器日志中，所以我们能够通过这种方式找到它。

我们有父->子和子->父进行双向导航，我们必须打破该链接并改为父->子，并且子有一个id来查找父，然后错误就消失了。

Answer 4

迁移到新服务器后出现同样的错误。 最终归结为缺少旧服务器上不需要的

targetFramework

属性......

<system.web>
  <httpRuntime enableVersionHeader="false" targetFramework="4.7.2"/>
</system.web>

Answer 5

将以下配置添加到您的 wcf 服务配置中。并查看 c:\log\Traces.svclog 文件。 我的异常被抛出；

尝试序列化参数时出错 InnerException 消息是“枚举值“0”对于类型“ThyCams2014.XrmBase.new_filingstatu”无效，并且无法序列化。确保存在必要的枚举值，并且如果该类型具有 DataContractAttribute attrienter 代码，则使用 EnumMemberAttribute 属性进行标记。'。请参阅 InnerException 了解更多详细信息。

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

Answer 6

这个说法解决了我的问题：

db.ContextConfiguration.ProxyCreationEnabled = false;