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Como: inspecionar e modificar mensagens do serviço

  • Artigo

Você pode inspecionar ou modificar as mensagens de entrada ou saída em um cliente WCF (Windows Communication Foundation) implementando um System.ServiceModel.Dispatcher.IDispatchMessageInspector e inserindo-o no tempo de execução do serviço. Para obter mais informações, confira Como estender Dispatchers. O recurso equivalente no serviço é o System.ServiceModel.Dispatcher.IClientMessageInspector.

Para inspecionar ou modificar mensagens

  1. Implemente a interface System.ServiceModel.Dispatcher.IDispatchMessageInspector.

  2. Implemente uma interface System.ServiceModel.Description.IServiceBehavior, System.ServiceModel.Description.IEndpointBehavior ou System.ServiceModel.Description.IContractBehavior dependendo do escopo no qual você deseja inserir facilmente o inspetor de mensagens de serviço.

  3. Insira seu comportamento antes de chamar o método ICommunicationObject.Open no System.ServiceModel.ServiceHost. Para obter detalhes, confira Configurar e estender o runtime com comportamentos.

Exemplo

Os exemplos de código a seguir mostram, em ordem:

  • Uma implementação de inspetor de serviço.

  • Um comportamento de serviço que insere o inspetor.

  • Um arquivo de configuração que carrega e executa o comportamento em um aplicativo de serviço.

#region IDispatchMessageInspector Members
public object AfterReceiveRequest(ref System.ServiceModel.Channels.Message request, IClientChannel channel, InstanceContext instanceContext)
{
  Console.WriteLine("IDispatchMessageInspector.AfterReceiveRequest called.");
  return null;
}

public void BeforeSendReply(ref System.ServiceModel.Channels.Message reply, object correlationState)
{
  Console.WriteLine("IDispatchMessageInspector.BeforeSendReply called.");
}
#endregion

#Region "IDispatchMessageInspector Members"
        Public Function AfterReceiveRequest(ByRef request As System.ServiceModel.Channels.Message, _
                           ByVal channel As IClientChannel, ByVal instanceContext As InstanceContext) _
                           As Object Implements IDispatchMessageInspector.AfterReceiveRequest
            Console.WriteLine("IDispatchMessageInspector.AfterReceiveRequest called.")
            Return Nothing
        End Function

        Public Sub BeforeSendReply(ByRef reply As System.ServiceModel.Channels.Message, ByVal correlationState As Object) _
        Implements IDispatchMessageInspector.BeforeSendReply
            Console.WriteLine("IDispatchMessageInspector.BeforeSendReply called.")
        End Sub
#End Region

#region IServiceBehavior Members
public void AddBindingParameters(
  ServiceDescription serviceDescription,
  ServiceHostBase serviceHostBase,
  System.Collections.ObjectModel.Collection<ServiceEndpoint> endpoints,
  BindingParameterCollection bindingParameters
)
{ return; }

public void ApplyDispatchBehavior(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase)
{
  foreach (ChannelDispatcher chDisp in serviceHostBase.ChannelDispatchers)
  {
    foreach (EndpointDispatcher epDisp in chDisp.Endpoints)
    {
      epDisp.DispatchRuntime.MessageInspectors.Add(new Inspector());
      foreach (DispatchOperation op in epDisp.DispatchRuntime.Operations)
        op.ParameterInspectors.Add(new Inspector());
    }
  }
}

#Region "IServiceBehavior Members"
        Public Sub AddBindingParameters(ByVal serviceDescription As ServiceDescription, _
                       ByVal serviceHostBase As ServiceHostBase, ByVal endpoints As _
                       System.Collections.ObjectModel.Collection(Of ServiceEndpoint), _
                       ByVal bindingParameters As BindingParameterCollection) Implements IServiceBehavior.AddBindingParameters
            Return
        End Sub

        Public Sub ApplyDispatchBehavior(ByVal serviceDescription As ServiceDescription, _
                                         ByVal serviceHostBase As ServiceHostBase) Implements _
                                         IServiceBehavior.ApplyDispatchBehavior
            For Each chDisp As ChannelDispatcher In serviceHostBase.ChannelDispatchers
                For Each epDisp As EndpointDispatcher In chDisp.Endpoints
                    epDisp.DispatchRuntime.MessageInspectors.Add(New Inspector())
                    For Each op As DispatchOperation In epDisp.DispatchRuntime.Operations
                        op.ParameterInspectors.Add(New Inspector())
                    Next op
                Next epDisp
            Next chDisp
        End Sub

<configuration>
  <system.serviceModel>
    <services>
      <service 
        name="Microsoft.WCF.Documentation.SampleService"
        behaviorConfiguration="metadataSupport">
        <host>
          <baseAddresses>
            <add baseAddress="http://localhost:8080/SampleService" />
          </baseAddresses>
        </host>
        <endpoint
          address=""
          binding="wsHttpBinding"
          contract="Microsoft.WCF.Documentation.ISampleService"
        />
        <endpoint
           address="mex"
           binding="mexHttpBinding"
           contract="IMetadataExchange"
        />
      </service>
    </services>
    <behaviors>
      <serviceBehaviors>
        <behavior name="metadataSupport">
          <serviceMetadata httpGetEnabled="true" httpGetUrl=""/>
          <serviceInterceptors />
        </behavior>
      </serviceBehaviors>
    </behaviors>
    <extensions>
      <behaviorExtensions>
        <add 
          name="serviceInterceptors" 
          type="Microsoft.WCF.Documentation.InspectorInserter, HostApplication, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null"
        />
      </behaviorExtensions>
    </extensions>
  </system.serviceModel>
</configuration>

Confira também