我正在学习使用WCF路由服务可以做些什么。仍然在与它拧紧，看它能做什么＆＃39;相。
我对路由服务的理解是，当消息通过时，服务将尝试将其传递给备份列表中首先出现的任何端点。如果失败了，它将继续尝试下一个，然后是下一个，直到任何一个有效或者没有什么可以尝试。
我想做的是访问该失败事件，以便我可以：
无法找到如何扩展WCF框架以获取此特定事件。
这是WCF路由服务可以做的事情吗？任何朝着正确方向的推动都会非常感激。
目前，我在IIS下托管了30-beh动态生成的路由服务（或更确切地说，是Visual Studio 2010的ASP.NET开发服务器）。我在Global.asax中设置了到服务的路由，如下所示。
protected void Application_Start(object sender, EventArgs e)
{
List<Type> serviceTypes = ServiceUtility.GetServiceTypes();
foreach (Type st in serviceTypes)
{
string route = String.Format("Services/{0}.svc", ServiceUtility.GetServiceName(st));
RouteTable.Routes.Add(new ServiceRoute(route, new RoutingServiceHostFactory(st), typeof(System.ServiceModel.Routing.RoutingService)));
}
}
ServiceUtility和RoutingServiceHostFactory是自定义类。请注意，IPolicyService是我感兴趣的程序集中的WCF服务契约接口。
public static class ServiceUtility
{
public static List<Type> GetServiceTypes()
{
Type policyInterfaceType = typeof(IPolicyService);
Assembly serviceContractsAssembly = Assembly.GetAssembly(policyInterfaceType);
Type[] serviceContractsAssemblyTypes = serviceContractsAssembly.GetTypes();
List<Type> serviceTypes = new List<Type>();
foreach (Type t in serviceContractsAssemblyTypes)
{
if (!t.IsInterface)
continue;
object[] attrib = t.GetCustomAttributes(typeof(ServiceContractAttribute), false);
if (attrib == null || attrib.Length <= 0)
continue;
serviceTypes.Add(t);
}
return serviceTypes;
}
// Other stuff
}
我按如下方式生成ServiceHosts。为简洁起见，我省略了一些辅助方法。
public class RoutingServiceHostFactory : ServiceHostFactory
{
private Type BackendServiceType { get; set; }
private Binding BackendServiceBinding { get; set; }
public RoutingServiceHostFactory(Type backendServiceType)
{
this.BackendServiceType = backendServiceType;
this.BackendServiceBinding = ServiceUtility.GetBinding(this.BackendServiceType);
}
private const string DOMAIN_LIVE = "http://localhost:2521/";
private const string DOMAIN_DEAD_1 = "http://localhost:2522/";
private const string DOMAIN_DEAD_2 = "http://localhost:2524/";
private const string DOMAIN_DEAD_3 = "http://localhost:2525/";
private const string DOMAIN_DEAD_4 = "http://localhost:2526/";
private const string DOMAIN_DEAD_5 = "http://localhost:2527/";
protected override ServiceHost CreateServiceHost(Type serviceType, Uri[] baseAddresses)
{
ServiceHost host = base.CreateServiceHost(serviceType, baseAddresses);
this.BindEndpoints(host, baseAddresses);
this.ConfigureRoutingBehavior(host);
this.ConfigureServiceMetadataBehavior(host);
this.ConfigureDebugBehavior(host);
host.Description.Behaviors.Add(new RoutingServiceErrorHandlerInjector());
return host;
}
// Other Stuff
private void ConfigureRoutingBehavior(ServiceHost host)
{
string deadAddress1 = ServiceUtility.GetServiceUrl(DOMAIN_DEAD_1, this.BackendServiceType);
string deadAddress2 = ServiceUtility.GetServiceUrl(DOMAIN_DEAD_2, this.BackendServiceType);
string deadAddress3 = ServiceUtility.GetServiceUrl(DOMAIN_DEAD_3, this.BackendServiceType);
string deadAddress4 = ServiceUtility.GetServiceUrl(DOMAIN_DEAD_4, this.BackendServiceType);
string deadAddress5 = ServiceUtility.GetServiceUrl(DOMAIN_DEAD_5, this.BackendServiceType);
string realAddress = ServiceUtility.GetServiceUrl(DOMAIN_LIVE, this.BackendServiceType);
RoutingConfiguration rc = new RoutingConfiguration();
ContractDescription contract = new ContractDescription("IRequestReplyRouter");
ServiceEndpoint deadDestination1 = new ServiceEndpoint(contract, this.BackendServiceBinding, new EndpointAddress(deadAddress1));
ServiceEndpoint deadDestination2 = new ServiceEndpoint(contract, this.BackendServiceBinding, new EndpointAddress(deadAddress2));
ServiceEndpoint deadDestination3 = new ServiceEndpoint(contract, this.BackendServiceBinding, new EndpointAddress(deadAddress3));
ServiceEndpoint deadDestination4 = new ServiceEndpoint(contract, this.BackendServiceBinding, new EndpointAddress(deadAddress4));
ServiceEndpoint deadDestination5 = new ServiceEndpoint(contract, this.BackendServiceBinding, new EndpointAddress(deadAddress5));
ServiceEndpoint realDestination = new ServiceEndpoint(contract, this.BackendServiceBinding, new EndpointAddress(realAddress));
List<ServiceEndpoint> backupList = new List<ServiceEndpoint>();
backupList.Add(deadDestination1);
backupList.Add(deadDestination2);
backupList.Add(deadDestination3);
backupList.Add(deadDestination4);
backupList.Add(deadDestination5);
backupList.Add(realDestination);
rc.FilterTable.Add(new MatchAllMessageFilter(), backupList);
RoutingBehavior rb = new RoutingBehavior(rc);
host.Description.Behaviors.Add(rb);
}
// Other Stuff
}
端口2521在另一端有一个托管一些WCF服务的实际网站。上面引用的其他端口没有任何监听。
对于上下文，这是我的路由站点的Web.config。请注意，超时等等只是我蠢蠢欲动的结果，不要太认真。
<?xml version="1.0"?>
<configuration>
<system.web>
<compilation debug="true" targetFramework="4.0" />
</system.web>
<system.serviceModel>
<serviceHostingEnvironment aspNetCompatibilityEnabled="true" />
<bindings>
<wsHttpBinding>
<binding
name="TestBinding"
allowCookies="True"
closeTimeout="00:04:00"
openTimeout="00:00:10"
receiveTimeout="00:05:00"
sendTimeout="00:05:00"
maxReceivedMessageSize="15728640">
<security>
<message establishSecurityContext="true" />
</security>
</binding>
</wsHttpBinding>
</bindings>
</system.serviceModel>
</configuration>
修改
为了回应下面的TheDoctor的回答，我想我应该扩展自我最初发布以来我尝试过的解决方案。我尝试过实现IErrorHandler接口。但是，我没有多少运气。
请注意，在上面的示例中，我的RoutingServiceHostFactory略有改变。我现在将RoutingServiceErrorHandlerInjector行为添加到服务描述中。请注意，为了说明，我还在备份列表中添加了额外的死端点。
public class RoutingServiceErrorHandlerInjector : IServiceBehavior
{
#region IServiceBehavior Members
public void AddBindingParameters(ServiceDescription serviceDescription, System.ServiceModel.ServiceHostBase serviceHostBase, System.Collections.ObjectModel.Collection<ServiceEndpoint> endpoints, System.ServiceModel.Channels.BindingParameterCollection bindingParameters)
{
}
public void ApplyDispatchBehavior(ServiceDescription serviceDescription, System.ServiceModel.ServiceHostBase serviceHostBase)
{
foreach (ChannelDispatcher chanDisp in serviceHostBase.ChannelDispatchers)
{
chanDisp.ErrorHandlers.Add(new RoutingServiceErrorHandler());
}
}
public void Validate(ServiceDescription serviceDescription, System.ServiceModel.ServiceHostBase serviceHostBase)
{
}
#endregion
}
public class RoutingServiceErrorHandler : IErrorHandler
{
#region IErrorHandler Members
public bool HandleError(Exception error)
{
throw new NotImplementedException(error.Message, error);
}
public void ProvideFault(Exception error, MessageVersion version, ref Message fault)
{
throw new NotImplementedException(error.Message, error);
}
#endregion
}
我的期望是我应该为deadDestination1到deadDestination5触发ProvideFault或HandleError事件。我在调试器中的NotImplementedExceptions上有断点。 但该代码永远不会被激活。调用最终将其传递到备份列表末尾的实际地址，而我用来测试此RoutingService的客户端/服务器应用程序运行正常。通信速度较慢，但仍在超时限制范围内。
但是，如果我从上面的ConfigureRoutingBehavior方法中注释掉行backupList.Add(realDestination);，那么可以执行RoutingServiceErrorHandler.ProvideFault方法...但它只包含与deadDestination5相关的信息。可能为deadDestination1到deadDestination4生成的任何异常或错误都会消失在我身上。
此外，我已经开始使用RedGate调试器逐步完成RoutingService的反射代码。这对我来说很棘手，因为我不习惯调试优化代码，因此几乎没有任何变量可供我实际阅读。但是，从以下逻辑的逐步观察：
// This has been taken from System.ServiceModel.Routing.RoutingService
// via the RedGate decompiler - unsure about it's ultimate accuracy.
[AspNetCompatibilityRequirements(RequirementsMode=AspNetCompatibilityRequirementsMode.Allowed), ServiceBehavior(AddressFilterMode=AddressFilterMode.Any, InstanceContextMode=InstanceContextMode.PerSession, UseSynchronizationContext=false, ValidateMustUnderstand=false)]
public sealed class RoutingService : ISimplexDatagramRouter, ISimplexSessionRouter, IRequestReplyRouter, IDuplexSessionRouter, IDisposable
{
[OperationBehavior(Impersonation=ImpersonationOption.Allowed), TargetedPatchingOptOut("Performance critical to inline this type of method across NGen image boundaries")]
IAsyncResult IRequestReplyRouter.BeginProcessRequest(Message message, AsyncCallback callback, object state)
{
return this.BeginProcessRequest<IRequestReplyRouter>(message, callback, state);
}
private IAsyncResult BeginProcessRequest<TContract>(Message message, AsyncCallback callback, object state)
{
IAsyncResult result;
try
{
System.ServiceModel.Routing.FxTrace.Trace.SetAndTraceTransfer(this.ChannelExtension.ActivityID, true);
result = new ProcessRequestAsyncResult<TContract>(this, message, callback, state);
}
catch (Exception exception)
{
if (TD.RoutingServiceProcessingFailureIsEnabled())
{
TD.RoutingServiceProcessingFailure(this.eventTraceActivity, OperationContext.Current.Channel.LocalAddress.ToString(), exception);
}
throw;
}
return result;
}
}
System.ServiceModel.Routing.ProcessRequestAsyncResult的相关部分如下所示。这些也是通过RedGate进行调试，因此无法修改。我相信RedGate和微软发布的消息来源是准确的。 #hesaiddubiously
internal class ProcessRequestAsyncResult<TContract> : TransactedAsyncResult
{
public ProcessRequestAsyncResult(RoutingService service, Message message, AsyncCallback callback, object state) : base(callback, state)
{
this.allCompletedSync = true;
this.service = service;
this.messageRpc = new System.ServiceModel.Routing.MessageRpc(message, OperationContext.Current, service.ChannelExtension.ImpersonationRequired);
if (TD.RoutingServiceProcessingMessageIsEnabled())
{
TD.RoutingServiceProcessingMessage(this.messageRpc.EventTraceActivity, this.messageRpc.UniqueID, message.Headers.Action, this.messageRpc.OperationContext.EndpointDispatcher.EndpointAddress.Uri.ToString(), (this.messageRpc.Transaction != null) ? "True" : "False");
}
try
{
EndpointNameMessageFilter.Set(this.messageRpc.Message.Properties, service.ChannelExtension.EndpointName);
this.messageRpc.RouteToSingleEndpoint<TContract>(this.service.RoutingConfig);
}
catch (MultipleFilterMatchesException exception)
{
throw System.ServiceModel.Routing.FxTrace.Exception.AsError(new ConfigurationErrorsException(System.ServiceModel.Routing.SR.ReqReplyMulticastNotSupported(this.messageRpc.OperationContext.Channel.LocalAddress), exception));
}
while (this.StartProcessing())
{
}
}
private bool StartProcessing()
{
bool flag = false;
SendOperation operation = this.messageRpc.Operations[0];
this.currentClient = this.service.GetOrCreateClient<TContract>(operation.CurrentEndpoint, this.messageRpc.Impersonating);
if (TD.RoutingServiceTransmittingMessageIsEnabled())
{
TD.RoutingServiceTransmittingMessage(this.messageRpc.EventTraceActivity, this.messageRpc.UniqueID, "0", this.currentClient.Key.ToString());
}
try
{
Message message;
if ((this.messageRpc.Transaction != null) && operation.HasAlternate)
{
throw System.ServiceModel.Routing.FxTrace.Exception.AsError(new ConfigurationErrorsException(System.ServiceModel.Routing.SR.ErrorHandlingNotSupportedReqReplyTxn(this.messageRpc.OperationContext.Channel.LocalAddress)));
}
if (operation.AlternateEndpointCount > 0)
{
message = this.messageRpc.CreateBuffer().CreateMessage();
}
else
{
message = this.messageRpc.Message;
}
operation.PrepareMessage(message);
IAsyncResult result = null;
using (base.PrepareTransactionalCall(this.messageRpc.Transaction))
{
using (IDisposable disposable = null)
{
try
{
}
finally
{
disposable = this.messageRpc.PrepareCall();
}
result = this.currentClient.BeginOperation(message, this.messageRpc.Transaction, base.PrepareAsyncCompletion(ProcessRequestAsyncResult<TContract>.operationCallback), this);
}
}
if (!base.CheckSyncContinue(result))
{
return flag;
}
if (this.OperationComplete(result))
{
base.Complete(this.allCompletedSync);
return flag;
}
return true;
}
catch (Exception exception)
{
if (Fx.IsFatal(exception))
{
throw;
}
if (!this.HandleClientOperationFailure(exception))
{
throw;
}
return true;
}
}
}
在我的肤浅阅读中，在我看来，ProcessRequestAsyncResult正在通过ProcessRequestAsyncResult.StartProcessing方法执行逐步执行备份列表的工作。但是，StartProcess（）似乎并没有抛出每个异常，而是选择性地选择是否抛出异常。
似乎只有最终死地址的异常实际上是由StartProcess（）引发的，然后由RoutingService.BeginProcessRequest catch子句传递，然后最终在IErrorHandler实现中一直激活它
这强烈告诉我，我在这里尝试做的事情无法通过System.ServiceModel.Routing命名空间的当前实现来完成。请注意，RoutingService是一个密封类，所以我不能用自己的基类来扩展它来改变这种行为，即使我认为这是一个好主意（我不会这样做）。
但话说回来，请注意这是肤浅的阅读。我很容易出错。事实上，我非常喜欢被证明是错误的。我非常希望找到一种方法让RoutingService按照我的意愿去做，而不是自己动手。
答案 0 :(得分：0)
WCF提供错误处理（http://msdn.microsoft.com/en-us/library/ee517422.aspx），因此您可以创建一个在CommunicationException（http://msdn.microsoft.com/en-us/library/system.servicemodel.communicationexception.aspx）上激活的函数，并记录传递给函数的数据中的错误代码。您可以从那里转到邮件生根服务以及您需要的任何其他内容。