WCF PollingDuplexHttpBinding與Silverlight客戶端超時和錯誤

Question

我正在構建一個具有自托管WCF服務的WPF 3.5桌面應用程序。

該服務具有如下定義的PollingDuplexHttpBinding端點：

public static void StartService()
    {
        var selfHost = new ServiceHost(Singleton, new Uri("http://localhost:1155/"));

        selfHost.AddServiceEndpoint(
            typeof(IMyService), 
            new PollingDuplexHttpBinding(PollingDuplexMode.MultipleMessagesPerPoll) {ReceiveTimeout = new TimeSpan(1,0,0,0)},
            "MyService"
        );

        ServiceMetadataBehavior smb = new ServiceMetadataBehavior();
        smb.HttpGetEnabled = true;
        selfHost.Description.Behaviors.Add(smb);

        selfHost.AddServiceEndpoint(typeof(IPolicyRetriever), new WebHttpBinding(), "").Behaviors.Add(new WebHttpBehavior());

        selfHost.Open();
    }

注意：IPolicyRetriever是一種允許我定義策略文件的服務

這有效，我可以在我的客戶端Silverlight應用程序中看到我的服務。 然后我在Silverlight代碼中創建對代理的引用，如下所示：

        EndpointAddress address = new EndpointAddress("http://localhost:1155/MyService");

        PollingDuplexHttpBinding binding = new PollingDuplexHttpBinding(PollingDuplexMode.MultipleMessagesPerPoll);
        binding.ReceiveTimeout = new TimeSpan(1, 0, 0, 0);
        _proxy = new MyServiceClient(binding, address);
        _proxy.ReceiveReceived += MessageFromServer;
        _proxy.OrderAsync("Test", 4);

這也很好，通訊工作！

但如果我不管它（即不要從服務器發送消息）超過1分鍾，然后嘗試從WPF服務器應用程序向客戶端發送消息，我會收到超時錯誤，如下所示：

IOutputChannel在00:01:00之后嘗試發送超時。 增加傳遞給Send的調用的超時值或增加Binding上的SendTimeout值。 分配給此操作的時間可能是較長超時的一部分。

它全部運行在localhost上，確實不應該有延遲，更不用說延遲1分鍾了。 我不知道為什么，但頻道似乎關閉或丟失或某事......

我也嘗試刪除綁定上的超時，我得到這樣的錯誤

通信對象System.ServiceModel.Channels.ServiceChannel不能用於通信，因為它已被中止

我怎樣才能在這里找出錯誤的信息？

Answer 1

WPF使用wsDualHttpBinding，Silverlight - Polling Duplex。 WPF解決方案很簡單; Silverlight需要ServiceHostFactory和更多代碼。 此外，Silverlight Server從不發送消息，而是客戶端輪詢服務器並檢索其消息。

在使用PollingDuplexHttpBinding的許多問題之后，我決定使用不帶MultipleMessagesPerPoll的CustomBinding。

web.config中

<system.serviceModel>
    <behaviors>
        <serviceBehaviors>
            <behavior name="SlApp.Web.DuplexServiceBehavior">
                <serviceMetadata httpGetEnabled="true" />
                <serviceDebug includeExceptionDetailInFaults="true" />
            </behavior>
        </serviceBehaviors>
    </behaviors>

  <serviceHostingEnvironment aspNetCompatibilityEnabled="true" multipleSiteBindingsEnabled="true" />

    <services>
        <service behaviorConfiguration="SlApp.Web.DuplexServiceBehavior" name="SlApp.Web.DuplexService">
            <endpoint address="WS" binding="wsDualHttpBinding" contract="SlApp.Web.DuplexService" />
            <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" />
        </service>
    </services>      
</system.serviceModel>

DuplexService.svc：

<%@ ServiceHost Language="C#" Debug="true" Service="SlApp.Web.DuplexService" Factory="SlApp.Web.DuplexServiceHostFactory" %>

DuplexServiceHostFactory.cs：

    public class DuplexServiceHostFactory : ServiceHostFactoryBase
    {
        public override ServiceHostBase CreateServiceHost(string constructorString, Uri[] baseAddresses)
        {
            return new DuplexServiceHost(baseAddresses);
        }
    }

    class DuplexServiceHost : ServiceHost
    {
        public DuplexServiceHost(params Uri[] addresses)
        {
            base.InitializeDescription(typeof(DuplexService), new UriSchemeKeyedCollection(addresses));
        }

        protected override void InitializeRuntime()
        {
            PollingDuplexBindingElement pdbe = new PollingDuplexBindingElement()
            {
                ServerPollTimeout = TimeSpan.FromSeconds(3),
                //Duration to wait before the channel is closed due to inactivity
                InactivityTimeout = TimeSpan.FromHours(24)
            };

            this.AddServiceEndpoint(typeof(DuplexService),
                new CustomBinding(
                    pdbe,
                    new BinaryMessageEncodingBindingElement(),
                    new HttpTransportBindingElement()), string.Empty);

            base.InitializeRuntime();
        }
    }

Silverlight客戶端代碼：

address = new EndpointAddress("http://localhost:43000/DuplexService.svc");
binding = new CustomBinding(
            new PollingDuplexBindingElement(),
            new BinaryMessageEncodingBindingElement(),
            new HttpTransportBindingElement()
        );
proxy = new DuplexServiceClient(binding, address);