深入理解WCF系统体系(之二:WCF客户端如何构建？（上))
前一节(《WCF体系架构(之一:Client与Server信息交互处理流程初略介绍)》)大致介绍了WCF服务消息处理的大致流程，WCF服务的消费者可以是WEB客户端、也可以是其他语言开发的应用程序。
对于WEB客户端以及其他语言的应用程序，跨平台的性能主要是通过HTTP协议+SOAP消息机制实现。本节主要详细介绍消息在WCF客户端应用程序消息处理流程
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-目录：
-1、WCF通过客户端代理调用 服务
-2、实际代理如何映射到服务目标对象上
-3、WCF客户端框架的核心ClientRuntime建立过程
-4、ImmutableClientRuntime对象的作用
-5、客户端操作选择器MethodInfoOperationSelector
-6、ProxyOperationRuntime的作用
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1、WCF如何处理客户端消息调
如果有.Net Remoting开发经验，大家一定还记得在Remoting的客户端，调用服务通过透明代理(TransparentProxy)来对服务进行调用，然后透明代理将对服务的调用转交给实际代理(RealProxy)。在WCF同样如此。那透明代理对应的实际代理又是什么类型的呢。？看看下面的测试例子就知道了。
var instanceContext = new InstanceContext(new CalculatorCallback());
using (var channkeFactory = new DuplexChannelFactory<ICalculator>(instanceContext, "calculator"))
{
ICalculator proxy = channkeFactory.CreateChannel();
Console.WriteLine("是否是透明代 理："+RemotingServices.IsTransparentProxy(proxy));
Console.WriteLine("透明代理类型:" + proxy.GetType());
}
输出结果如下：
2、实际代理如何映射到服务目标对象上
首先看看实际代理对象ServiceChannelProxy字段的定义：
internal sealed class ServiceChannelProxy : RealProxy, IRemotingTypeInfo
{
// Fields
private const string activityIdSlotName = "E2ETrace.ActivityID";
private Type interfaceType;
private MethodDataCache methodDataCache;
private MbrObject objectWrapper;
private Type proxiedType;
private ImmutableClientRuntime proxyRuntime;
private ServiceChannel serviceChannel;
/*
*/
public override IMessage Invoke(IMessage message)
{
IMessage message3;
try
{
IMethodCallMessage methodCall = message as IMethodCallMessage;
if (methodCall == null)
{
throw DiagnosticUtility.ExceptionUtility.ThrowHelperError(new ArgumentException(SR.GetString("SFxExpectedIMethodCallMessage")));
}
MethodData methodData = this.GetMethodData(methodCall);
switch (methodData.MethodType)
{
case MethodType.Service:
return this.InvokeService(methodCall, methodData.Operation);
case MethodType.BeginService:
return this.InvokeBeginService(methodCall, methodData.Operation);
case MethodType.EndService:
return this.InvokeEndService(methodCall, methodData.Operation);
case MethodType.Channel:
return this.InvokeChannel(methodCall);
case MethodType.Object:
return this.InvokeObject(methodCall);
case MethodType.GetType:
return this.InvokeGetType(methodCall);
}
throw DiagnosticUtility.ExceptionUtility.ThrowHelperError(new InvalidOperationException(string.Format(CultureInfo.InvariantCulture, "Invalid proxy method type", new object[0])));
}
catch (Exception exception)
{
if (Fx.IsFatal(exception))
{
throw;
}
message3 = this.CreateReturnMessage(exception, message as IMethodCallMessage);
}
return message3;
}
private IMethodReturnMessage InvokeService(IMethodCallMessage methodCall, ProxyOperationRuntime operation)
{
object[] objArray;
object[] ins = operation.MapSyncInputs(methodCall, out objArray);
object ret = this.serviceChannel.Call(operation.Action, operation.IsOneWay, operation, ins, objArray);
object[] returnArgs = operation.MapSyncOutputs(methodCall, objArray, ref ret);
return this.CreateReturnMessage(ret, returnArgs, methodCall);
}
}
先对这几个对象做个介绍：
- interfaceType与proxiedType就是服务契约的Type，methodDataCache存放方法信息的容器
- objectWrapper：建立代理对象与服务对象之间映射关系的对象
- proxyRuntime：是恒定客户端运行时(这个是我自己翻译的，只在此有意义。为了区分它与客户端运行时ClientRuntime的区别而已)。同ClientRuntime一样，它也是WCF客户端体系中很重要的一个对象，它涉及到调用信息的序列化、反序列化、IClientOperationsSelector、IClientMessageInspector、IChannelInitializer等核心对象，稍后会介绍到。
- serviceChannel：服务信道。
其中有个 MbrObject类型的 objectWrapper定义。MbrObject的定义如下：
private class MbrObject : MarshalByRefObject
{
// Fields
private RealProxy proxy;
private Type targetType;
// Methods
internal MbrObject(RealProxy proxy, Type targetType)
{
this.proxy = proxy;
this.targetType = targetType;
}
public override bool Equals(object obj)
{
return object.ReferenceEquals(obj, this.proxy.GetTransparentProxy());
}
public override int GetHashCode()
{
return this.proxy.GetHashCode();
}
public override string ToString()
{
return this.targetType.ToString();
}
}
看看它的构造函数使用的参数可知：通过实际代理对象以及目标代理类型，将实际代理对象映射到了实现契约接口的对象上。
还有个问题：RealProxy是映射到了最终服务对象上，那是通过什么样的方式或者说是如何进行映射的呢。？
ServiceChannelProxy对象在WCF体系内部构造ServiceChannelProxy对象时有个构造函数，它建立了代理对象与实际服务对象：this.objectWrapper = new MbrObject(this, proxiedType);这样就建立了代理对象同服务对象之间的映射。
查看代理信息就发现了他们之间的关系，如下图：
客户端调用服务端方法最终通过ServiceChannelProxy进行调用。以上只列出了同步调用的方法，在ServiceChannelFactory中还有异步调用的方法，详情请参见ServiceChannelFactory类。
从InvokeService中可以看出，进行调用的时候，使用了serviceChannel.Call进行调用。同样，在异步方法中也是通过ServiceChannel对象的BeginInvoke与EndInvoke进行调用。也就是说最终的调用是通过ServiceChannel完成。
3、WCF客户端框架的核心ClientRuntime建立过程
ClientRuntime是与WCF服务端框架中DispatchRuntime对应的客户端框架的核心。那么ClientRuntime是如何建立的。？
ClientRuntime建立的过程比较复杂。下面通过序号标明ClientRuntime建立的过程。
3.1、建立Channel
无论在WCF的客户端还是服务端，我们通常都会选择一种或者多种通信协议。绑定协议包含许多绑定元素(BindingElementCollection)。以NetTcpBinding来说，它就包含 以下四种绑定元素：
TransactionFlowBindingElement context;
BinaryMessageEncodingBindingElement encoding;
ReliableSessionBindingElement session;
TcpTransportBindingElement transport;
每个绑定元素穿件信道工厂，BindingElementCollection创建的是信道工厂堆栈，信道就是由这些ChannelFactory Stack按照顺序依次建立起来的Channel Stack。
3.2、建立过程ChannelFactory
先看看以下例子：var channkeFactory = new DuplexChannelFactory<ICalculator>(instanceContext, "calculator")；这样就信道工厂就建立。在这个例子中用回调对象对象与EndpointName为参数建立ChannelFactory。
DuplexChannelFactory有很多构造器，
public class DuplexChannelFactory<TChannel> : ChannelFactory<TChannel>
{
// Methods
public DuplexChannelFactory(object callbackObject) : base(typeof(TChannel))
{
using (ServiceModelActivity activity = DiagnosticUtility.ShouldUseActivity ? ServiceModelActivity.CreateBoundedActivity() : null)
{
if (DiagnosticUtility.ShouldUseActivity)
{
ServiceModelActivity.Start(activity, SR.GetString("ActivityConstructChannelFactory", new object[] { TraceUtility.CreateSourceString(this) }), ActivityType.Construct);
}
if (callbackObject == null)
{
throw DiagnosticUtility.ExceptionUtility.ThrowHelperArgumentNull("callbackObject");
}
this.CheckAndAssignCallbackInstance(callbackObject);
base.InitializeEndpoint((string) null, null);
}
}
public DuplexChannelFactory(object callbackObject, string endpointConfigurationName) : this(callbackObject, endpointConfigurationName, (EndpointAddress) null)
{
}
public DuplexChannelFactory(object callbackObject, string endpointConfigurationName, EndpointAddress remoteAddress) : base(typeof(TChannel))
{
using (ServiceModelActivity activity = DiagnosticUtility.ShouldUseActivity ? ServiceModelActivity.CreateBoundedActivity() : null)
{
if (DiagnosticUtility.ShouldUseActivity)
{
ServiceModelActivity.Start(activity, SR.GetString("ActivityConstructChannelFactory", new object[] { TraceUtility.CreateSourceString(this) }), ActivityType.Construct);
}
if (callbackObject == null)
{
throw DiagnosticUtility.ExceptionUtility.ThrowHelperArgumentNull("callbackObject");
}
if (endpointConfigurationName == null)
{
throw DiagnosticUtility.ExceptionUtility.ThrowHelperArgumentNull("endpointConfigurationName");
}
this.CheckAndAssignCallbackInstance(callbackObject);
base.InitializeEndpoint(endpointConfigurationName, remoteAddress);
}
}
/*
......
*/
}
以上列举了上述例子中使用的构造器。从中可知：在创建ChannelFactory的过程中，通过ChannelFactory<TChannel>的InitializeEndpoint对Endpoint进行了初始化。
3.3、根据建立的Endpoint创建ServiceChannelFactory
internal abstract class ServiceChannelFactory : ChannelFactoryBase
{
public static ServiceChannelFactory BuildChannelFactory(ServiceEndpoint serviceEndpoint, bool useActiveAutoClose)
{
ChannelRequirements requirements;
BindingParameterCollection parameters;
if (serviceEndpoint == null)
{
throw DiagnosticUtility.ExceptionUtility.ThrowHelperArgumentNull("serviceEndpoint");
}
serviceEndpoint.EnsureInvariants();
serviceEndpoint.ValidateForClient();
ChannelRequirements.ComputeContractRequirements(serviceEndpoint.Contract, out requirements);
ClientRuntime clientRuntime = DispatcherBuilder.BuildProxyBehavior(serviceEndpoint, out parameters);
Binding binding = serviceEndpoint.Binding;
Type[] requiredChannels = ChannelRequirements.ComputeRequiredChannels(ref requirements);
CustomBinding binding2 = new CustomBinding(binding);
BindingContext context = new BindingContext(binding2, parameters);
InternalDuplexBindingElement internalDuplexBindingElement = null;
InternalDuplexBindingElement.AddDuplexFactorySupport(context, ref internalDuplexBindingElement);
binding2 = new CustomBinding(context.RemainingBindingElements);
binding2.CopyTimeouts(serviceEndpoint.Binding);
foreach (Type type in requiredChannels)
{
if ((type == typeof(IOutputChannel)) && binding2.CanBuildChannelFactory<IOutputChannel>(parameters))
{
return new ServiceChannelFactoryOverOutput(binding2.BuildChannelFactory<IOutputChannel>(parameters), clientRuntime, binding);
}
if ((type == typeof(IRequestChannel)) && binding2.CanBuildChannelFactory<IRequestChannel>(parameters))
{
return new ServiceChannelFactoryOverRequest(binding2.BuildChannelFactory<IRequestChannel>(parameters), clientRuntime, binding);
}
if ((type == typeof(IDuplexChannel)) && binding2.CanBuildChannelFactory<IDuplexChannel>(parameters))
{
if (requirements.usesReply && binding.CreateBindingElements().Find<TransportBindingElement>().ManualAddressing)
{
throw DiagnosticUtility.ExceptionUtility.ThrowHelperError(new InvalidOperationException(SR.GetString("CantCreateChannelWithManualAddressing")));
}
return new ServiceChannelFactoryOverDuplex(binding2.BuildChannelFactory<IDuplexChannel>(parameters), clientRuntime, binding);
}
if ((type == typeof(IOutputSessionChannel)) && binding2.CanBuildChannelFactory<IOutputSessionChannel>(parameters))
{
return new ServiceChannelFactoryOverOutputSession(binding2.BuildChannelFactory<IOutputSessionChannel>(parameters), clientRuntime, binding, false);
}
if ((type == typeof(IRequestSessionChannel)) && binding2.CanBuildChannelFactory<IRequestSessionChannel>(parameters))
{
return new ServiceChannelFactoryOverRequestSession(binding2.BuildChannelFactory<IRequestSessionChannel>(parameters), clientRuntime, binding, false);
}
if ((type == typeof(IDuplexSessionChannel)) && binding2.CanBuildChannelFactory<IDuplexSessionChannel>(parameters))
{
if (requirements.usesReply && binding.CreateBindingElements().Find<TransportBindingElement>().ManualAddressing)
{
throw DiagnosticUtility.ExceptionUtility.ThrowHelperError(new InvalidOperationException(SR.GetString("CantCreateChannelWithManualAddressing")));
}
return new ServiceChannelFactoryOverDuplexSession(binding2.BuildChannelFactory<IDuplexSessionChannel>(parameters), clientRuntime, binding, useActiveAutoClose);
}
}
foreach (Type type2 in requiredChannels)
{
if ((type2 == typeof(IOutputChannel)) && binding2.CanBuildChannelFactory<IOutputSessionChannel>(parameters))
{
return new ServiceChannelFactoryOverOutputSession(binding2.BuildChannelFactory<IOutputSessionChannel>(parameters), clientRuntime, binding, true);
}
if ((type2 == typeof(IRequestChannel)) && binding2.CanBuildChannelFactory<IRequestSessionChannel>(parameters))
{
return new ServiceChannelFactoryOverRequestSession(binding2.BuildChannelFactory<IRequestSessionChannel>(parameters), clientRuntime, binding, true);
}
if (((type2 == typeof(IRequestSessionChannel)) && binding2.CanBuildChannelFactory<IRequestChannel>(parameters)) && (binding2.GetProperty<IContextSessionProvider>(parameters) != null))
{
return new ServiceChannelFactoryOverRequest(binding2.BuildChannelFactory<IRequestChannel>(parameters), clientRuntime, binding);
}
}
Dictionary<Type, byte> dictionary = new Dictionary<Type, byte>();
if (binding2.CanBuildChannelFactory<IOutputChannel>(parameters))
{
dictionary.Add(typeof(IOutputChannel), 0);
}
if (binding2.CanBuildChannelFactory<IRequestChannel>(parameters))
{
dictionary.Add(typeof(IRequestChannel), 0);
}
if (binding2.CanBuildChannelFactory<IDuplexChannel>(parameters))
{
dictionary.Add(typeof(IDuplexChannel), 0);
}
if (binding2.CanBuildChannelFactory<IOutputSessionChannel>(parameters))
{
dictionary.Add(typeof(IOutputSessionChannel), 0);
}
if (binding2.CanBuildChannelFactory<IRequestSessionChannel>(parameters))
{
dictionary.Add(typeof(IRequestSessionChannel), 0);
}
if (binding2.CanBuildChannelFactory<IDuplexSessionChannel>(parameters))
{
dictionary.Add(typeof(IDuplexSessionChannel), 0);
}
throw DiagnosticUtility.ExceptionUtility.ThrowHelperError(ChannelRequirements.CantCreateChannelException(dictionary.Keys, requiredChannels, binding.Name));
}
}
从ClientRuntime clientRuntime = DispatcherBuilder.BuildProxyBehavior(serviceEndpoint, out parameters);
可知：ClientRuntime 由DispatcherBuilder创建。
注：ServiceChannel由ServiceChannelFactory创建，同ServiceChannelProxy使用。在创建ServiceChannel的过程中对Channel进行初始化。处理函数如下：
public object CreateChannel(Type channelType, EndpointAddress address, Uri via)
{
if (via == null)
{
via = this.ClientRuntime.Via;
if (via == null)
{
via = address.Uri;
}
}
ServiceChannel serviceChannel = this.CreateServiceChannel(address, via);
serviceChannel.Proxy = CreateProxy(channelType, channelType, MessageDirection.Input, serviceChanne);
serviceChannel.ClientRuntime.GetRuntime().InitializeChannel((IClientChannel) serviceChannel.Proxy);
OperationContext current = OperationContext.Current;
if ((current != null) && (current.InstanceContext != null))
{
current.InstanceContext.WmiChannels.Add((IChannel) serviceChannel.Proxy);
serviceChannel.WmiInstanceContext = current.InstanceContext;
}
return serviceChannel.Proxy;
}
3.4、DispatcherBuilder创建ClientRuntime
internal class DispatcherBuilder
{
internal static ClientRuntime BuildProxyBehavior(ServiceEndpoint serviceEndpoint, out BindingParameterCollection parameters)
{
parameters = new BindingParameterCollection();
SecurityContractInformationEndpointBehavior.ClientInstance.AddBindingParameters(serviceEndpoint, parameters);
AddBindingParameters(serviceEndpoint, parameters);
ContractDescription contract = serviceEndpoint.Contract;
ClientRuntime parent = new ClientRuntime(contract.Name, contract.Namespace);
parent.ContractClientType = contract.ContractType;
IdentityVerifier property = serviceEndpoint.Binding.GetProperty<IdentityVerifier>(parameters);
if (property != null)
{
parent.IdentityVerifier = property;
}
for (int i = 0; i < contract.Operations.Count; i++)
{
OperationDescription operation = contract.Operations[i];
if (!operation.IsServerInitiated())
{
BuildProxyOperation(operation, parent);
}
else
{
BuildDispatchOperation(operation, parent.CallbackDispatchRuntime, null);
}
}
ApplyClientBehavior(serviceEndpoint, parent);
return parent;
}
/**/
}
由Endpoint信息可以获取到ContractDescription，进而获取到Operations等等，从而赋值给ClientRuntime对象，完成ClientRuntime对象的建立。
以上还有个问题：DispatchRuntime 是与ClientRuntime相对象的WCF服务端分发运行时，同ClientRuntime一样，它是WCF服务端核心对象。在客户端怎么会后服务端的的分发运行时呢。？原因很简单，在WCF数据包模式以及Request-Reply模式下，DispatchRuntime是不需要的，但是在双工模式时，Server端与Client端已经不明确，
Server与Client互发消息，即是服务端也是客户端。所以不仅在ClientRuntime中存在DispatchRuntime，在DispatchRuntime同样存在ClientRuntime。
ClientRuntime作为客户端框架的核心，它决定着消息的格式化(IClientMessageFormatter)、客户端操作选择器(IClientOperationSelector)、客户端消息检查器(IClientMessageInspectors)等等。
4、ImmutableClientRuntime对象的作用
客户端对服务端的操作是通过TransparentProxy到RealProxy，也就是ServiceChannelProxy对象中。上面提到过，客户端调用服务的实际代理ServiceChannelProxy对象有一个名称为proxyRuntime的字段，类型就是ImmutableClientRuntime。
ImmutableClientRuntime对象依赖于ClientRuntime，这点可以从ImmutableClientRuntime的构造函数中就可以看出。
internal ImmutableClientRuntime(ClientRuntime behavior)
{
this.channelInitializers = EmptyArray<IChannelInitializer>.ToArray(behavior.ChannelInitializers);
this.interactiveChannelInitializers = EmptyArray<IInteractiveChannelInitializer>.ToArray(behavior.InteractiveChannelInitializers);
this.messageInspectors = EmptyArray<IClientMessageInspector>.ToArray(behavior.MessageInspectors);
this.operationSelector = behavior.OperationSelector;
this.useSynchronizationContext = behavior.UseSynchronizationContext;
this.validateMustUnderstand = behavior.ValidateMustUnderstand;
this.unhandled = new ProxyOperationRuntime(behavior.UnhandledClientOperation, this);
this.addTransactionFlowProperties = behavior.AddTransactionFlowProperties;
this.operations = new Dictionary<string, ProxyOperationRuntime>();
for (int i = 0; i < behavior.Operations.Count; i++)
{
ClientOperation operation = behavior.Operations[i];
ProxyOperationRuntime runtime = new ProxyOperationRuntime(operation, this);
this.operations.Add(operation.Name, runtime);
}
this.correlationCount = this.messageInspectors.Length + behavior.MaxParameterInspectors;
}
ImmutableClientRuntime在RealProxy中起着至关重要的作用。如下图是RealProxy的信息：
由上图可知：
1、operations为Dictionary<string, ProxyOperationRuntime>类型，其中key为契约接口中标识位OperationContractAttribute的方法名，Value为ProxyOperationRuntime。
2、MessageInspector是实现了IClientMessageInspector接口的Microsoft.VisualStudio.Diagnostics.ServiceModelSink.StubClientEventSink类型。
3、客户端OperationSelector是MethodInfoOperationSelector类型的，MethodInfoOperationSelector实现了IClientOperationSelector接口。
4、客户端消息检查器IClientMessageInspectors为Microsoft.VisualStudio.Diagnostics.ServiceModelSink.StubClientEventSink类型。
5、客户端操作选择器MethodInfoOperationSelector。
通过工具看看MethodInfoOperationSelector的定义如下：
internal class MethodInfoOperationSelector : IClientOperationSelector
{
// Fields
private Dictionary<object, string> operationMap = new Dictionary<object, string>();
// Methods
internal MethodInfoOperationSelector(ContractDescription description, MessageDirection directionThatRequiresClientOpSelection)
{
for (int i = 0; i < description.Operations.Count; i++)
{
OperationDescription description2 = description.Operations[i];
if (description2.Messages[0].Direction == directionThatRequiresClientOpSelection)
{
if ((description2.SyncMethod != null) && !this.operationMap.ContainsKey(description2.SyncMethod.MethodHandle))
{
this.operationMap.Add(description2.SyncMethod.MethodHandle, description2.Name);
}
if ((description2.BeginMethod != null) && !this.operationMap.ContainsKey(description2.BeginMethod.MethodHandle))
{
this.operationMap.Add(description2.BeginMethod.MethodHandle, description2.Name);
this.operationMap.Add(description2.EndMethod.MethodHandle, description2.Name);
}
}
}
}
public string SelectOperation(MethodBase method, object[] parameters)
{
if (this.operationMap.ContainsKey(method.MethodHandle))
{
return this.operationMap[method.MethodHandle];
}
return null;
}
// Properties
public bool AreParametersRequiredForSelection
{
get
{
return false;
}
}
}
operationMap为存放方法的字段，key方法句柄信息，Value为方法名。
MethodInfoOperationSelector通过SelectOperation根据方法句柄值获取方法名，然后通过方法名，获取ProxyOperationRuntime对象。
查看OperationSelector的operationMap中Add方法的句柄值如下图所示：
通过控制台输出契约接口中方法的句柄值如下：
-6、ProxyOperationRuntime的作用
了解它的作用，还是从源码开始。
internal class ProxyOperationRuntime
{
// Fields
private string action;
private MethodInfo beginMethod;
private bool deserializeReply;
internal static readonly object[] EmptyArray = new object[0];
private ParameterInfo[] endOutParams;
private readonly IClientFaultFormatter faultFormatter;
private readonly IClientMessageFormatter formatter;
private ParameterInfo[] inParams;
private readonly bool isInitiating;
private readonly bool isOneWay;
private readonly bool isTerminating;
private readonly string name;
internal static readonly ParameterInfo[] NoParams = new ParameterInfo[0];
private ParameterInfo[] outParams;
private readonly IParameterInspector[] parameterInspectors;
private readonly ImmutableClientRuntime parent;
private string replyAction;
private ParameterInfo returnParam;
private bool serializeRequest;
private MethodInfo syncMethod;
// Methods
internal ProxyOperationRuntime(ClientOperation operation, ImmutableClientRuntime parent)
{
if (operation == null)
{
throw DiagnosticUtility.ExceptionUtility.ThrowHelperArgumentNull("operation");
}
if (parent == null)
{
throw DiagnosticUtility.ExceptionUtility.ThrowHelperArgumentNull("parent");
}
this.parent = parent;
this.formatter = operation.Formatter;
this.isInitiating = operation.IsInitiating;
this.isOneWay = operation.IsOneWay;
this.isTerminating = operation.IsTerminating;
this.name = operation.Name;
this.parameterInspectors = EmptyArray<IParameterInspector>.ToArray(operation.ParameterInspectors);
this.faultFormatter = operation.FaultFormatter;
this.serializeRequest = operation.SerializeRequest;
this.deserializeReply = operation.DeserializeReply;
this.action = operation.Action;
this.replyAction = operation.ReplyAction;
this.beginMethod = operation.BeginMethod;
this.syncMethod = operation.SyncMethod;
if (this.beginMethod != null)
{
this.inParams = ServiceReflector.GetInputParameters(this.beginMethod, true);
if (this.syncMethod != null)
{
this.outParams = ServiceReflector.GetOutputParameters(this.syncMethod, false);
}
else
{
this.outParams = NoParams;
}
this.endOutParams = ServiceReflector.GetOutputParameters(operation.EndMethod, true);
this.returnParam = operation.EndMethod.ReturnParameter;
}
else if (this.syncMethod != null)
{
this.inParams = ServiceReflector.GetInputParameters(this.syncMethod, false);
this.outParams = ServiceReflector.GetOutputParameters(this.syncMethod, false);
this.returnParam = this.syncMethod.ReturnParameter;
}
if ((this.formatter == null) && (this.serializeRequest || this.deserializeReply))
{
throw DiagnosticUtility.ExceptionUtility.ThrowHelperError(new InvalidOperationException(SR.GetString("ClientRuntimeRequiresFormatter0", new object[] { this.name })));
}
}
}
internal void AfterReply(ref ProxyRpc rpc)
{
if (!this.isOneWay)
{
Message reply = rpc.Reply;
if (this.deserializeReply)
{
rpc.ReturnValue = this.formatter.DeserializeReply(reply, rpc.OutputParameters);
}
else
{
rpc.ReturnValue = reply;
}
int parameterInspectorCorrelationOffset = this.parent.ParameterInspectorCorrelationOffset;
try
{
for (int i = this.parameterInspectors.Length - 1; i >= 0; i--)
{
this.parameterInspectors[i].AfterCall(this.name, rpc.OutputParameters, rpc.ReturnValue, rpc.Correlation[parameterInspectorCorrelationOffset + i]);
if (TD.ClientParameterInspectorAfterCallInvokedIsEnabled())
{
TD.ClientParameterInspectorAfterCallInvoked(this.parameterInspectors[i].GetType().FullName);
}
}
}
catch (Exception exception)
{
if (Fx.IsFatal(exception))
{
throw;
}
if (ErrorBehavior.ShouldRethrowClientSideExceptionAsIs(exception))
{
throw;
}
throw DiagnosticUtility.ExceptionUtility.ThrowHelperCallback(exception);
}
if (this.parent.ValidateMustUnderstand)
{
Collection<MessageHeaderInfo> headersNotUnderstood = reply.Headers.GetHeadersNotUnderstood();
if ((headersNotUnderstood != null) && (headersNotUnderstood.Count > 0))
{
throw DiagnosticUtility.ExceptionUtility.ThrowHelperError(new ProtocolException(SR.GetString("SFxHeaderNotUnderstood", new object[] { headersNotUnderstood[0].Name, headersNotUnderstood[0].Namespace })));
}
}
}
}
internal void BeforeRequest(ref ProxyRpc rpc)
{
int parameterInspectorCorrelationOffset = this.parent.ParameterInspectorCorrelationOffset;
try
{
for (int i = 0; i < this.parameterInspectors.Length; i++)
{
rpc.Correlation[parameterInspectorCorrelationOffset + i] = this.parameterInspectors[i].BeforeCall(this.name, rpc.InputParameters);
if (TD.ClientParameterInspectorBeforeCallInvokedIsEnabled())
{
TD.ClientParameterInspectorBeforeCallInvoked(this.parameterInspectors[i].GetType().FullName);
}
}
}
catch (Exception exception)
{
if (Fx.IsFatal(exception))
{
throw;
}
if (ErrorBehavior.ShouldRethrowClientSideExceptionAsIs(exception))
{
throw;
}
throw DiagnosticUtility.ExceptionUtility.ThrowHelperCallback(exception);
}
if (this.serializeRequest)
{
rpc.Request = this.formatter.SerializeRequest(rpc.MessageVersion, rpc.InputParameters);
}
else
{
if (rpc.InputParameters[0] == null)
{
throw DiagnosticUtility.ExceptionUtility.ThrowHelperError(new InvalidOperationException(SR.GetString("SFxProxyRuntimeMessageCannotBeNull", new object[] { this.name })));
}
rpc.Request = (Message) rpc.InputParameters[0];
if (!IsValidAction(rpc.Request, this.Action))
{
object[] args = new object[] { this.Name, rpc.Request.Headers.Action ?? "{NULL}", this.Action };
throw DiagnosticUtility.ExceptionUtility.ThrowHelperError(new InvalidOperationException(SR.GetString("SFxInvalidRequestAction", args)));
}
}
}
由上图可以得知：
1、对返回值进行序列化时，使用的类型是PrimitiveOperationFormatter,它同时实现了客户端序列化接口IClientMessageFormatter与服务端序列化IDispatchMessageFormatter接口
2、错误契约使用的序列化器是DataContractSerializerFaultFormatter。
3、对服务调用参数的序列化以及参数检查，对返回消息进行反序列化及参数检查通过ProxyOperationRuntime对象完成。
对实际代理ServiceChannelProxy对象中的ImmutableClientRuntime类型的字段realProxy以及realProxy的MessageInspector、operations添加监视，查看其信息如下：
图1：realProxy监视信息
图2：realProxy的消息检查器MessageInspector监视信息
图3：realProxy的operations监视信息
由以上3个图中显示的信息可知：
1、operations为Dictionary<string, ProxyOperationRuntime>类型，其中key为契约接口中标识位OperationContractAttribute的方法名，Value为ProxyOperationRuntime。
2、MessageInspector是实现了IClientMessageInspector接口的客户端消息检查器Microsoft.VisualStudio.Diagnostics.ServiceModelSink.StubClientEventSink类型。
3、客户端OperationSelector是MethodInfoOperationSelector类型的，MethodInfoOperationSelector实现了IClientOperationSelector接口。
参考：http://www.cnblogs.com/artech/tag/WCF/
《WCF揭秘》
