指定客户端运行时行为

项目
04/07/2023

Windows Communication Foundation (WCF) 客户端（如 Windows Communication Foundation (WCF) 服务）可以配置为修改运行时行为以适应客户端应用程序。有三个属性可用于指定客户端运行时行为。双工客户端回调对象可以使用 CallbackBehaviorAttribute 和 CallbackDebugBehavior 属性修改其运行时行为。另一个属性 ClientViaBehavior 可用于将逻辑目标与直接网络目标分开。此外，双工客户端回调类型可以使用某些服务端行为。有关详细信息，请参阅指定服务运行时行为。

使用 CallbackBehaviorAttribute

可以使用 CallbackBehaviorAttribute 类来配置或扩展客户端应用程序中回调协定实现的执行行为。此属性为回调类和 ServiceBehaviorAttribute 类执行相似的功能，不同之处在于实例化行为和事务设置。

必须将 CallbackBehaviorAttribute 类应用于实现回调协定的类。如果将其应用于非双工协定实现，则会在运行时引发 InvalidOperationException 异常。下面的代码示例演示回调对象上的一个 CallbackBehaviorAttribute 类，该类使用 SynchronizationContext 对象确定要封送到的线程，使用 ValidateMustUnderstand 属性强制执行消息验证，并使用 IncludeExceptionDetailInFaults 属性将异常作为 FaultException 对象返回给服务以便进行调试。

using System;
using System.ServiceModel;
using System.ServiceModel.Channels;
using System.Threading;

namespace Microsoft.WCF.Documentation
{
  [CallbackBehaviorAttribute(
   IncludeExceptionDetailInFaults= true,
    UseSynchronizationContext=true,
    ValidateMustUnderstand=true
  )]
  public class Client : SampleDuplexHelloCallback
  {
    AutoResetEvent waitHandle;

    public Client()
    {
      waitHandle = new AutoResetEvent(false);
    }

    public void Run()
    {
      // Picks up configuration from the configuration file.
      SampleDuplexHelloClient wcfClient
        = new SampleDuplexHelloClient(new InstanceContext(this), "WSDualHttpBinding_SampleDuplexHello");
      try
      {
        Console.ForegroundColor = ConsoleColor.White;
        Console.WriteLine("Enter a greeting to send and press ENTER: ");
        Console.Write(">>> ");
        Console.ForegroundColor = ConsoleColor.Green;
        string greeting = Console.ReadLine();
        Console.ForegroundColor = ConsoleColor.White;
        Console.WriteLine("Called service with: \r\n\t" + greeting);
        wcfClient.Hello(greeting);
        Console.WriteLine("Execution passes service call and moves to the WaitHandle.");
        this.waitHandle.WaitOne();
        Console.ForegroundColor = ConsoleColor.Blue;
        Console.WriteLine("Set was called.");
        Console.Write("Press ");
        Console.ForegroundColor = ConsoleColor.Red;
        Console.Write("ENTER");
        Console.ForegroundColor = ConsoleColor.Blue;
        Console.Write(" to exit...");
        Console.ReadLine();
      }
      catch (TimeoutException timeProblem)
      {
        Console.WriteLine("The service operation timed out. " + timeProblem.Message);
        Console.ReadLine();
      }
      catch (CommunicationException commProblem)
      {
        Console.WriteLine("There was a communication problem. " + commProblem.Message);
        Console.ReadLine();
      }
    }
    public static void Main()
    {
      Client client = new Client();
      client.Run();
    }

    public void Reply(string response)
    {
      Console.WriteLine("Received output.");
      Console.WriteLine("\r\n\t" + response);
      this.waitHandle.Set();
    }
  }
}


Imports System.ServiceModel
Imports System.ServiceModel.Channels
Imports System.Threading

Namespace Microsoft.WCF.Documentation
    <CallbackBehaviorAttribute(IncludeExceptionDetailInFaults:=True, UseSynchronizationContext:=True, ValidateMustUnderstand:=True)> _
    Public Class Client
        Implements SampleDuplexHelloCallback
        Private waitHandle As AutoResetEvent

        Public Sub New()
            waitHandle = New AutoResetEvent(False)
        End Sub

        Public Sub Run()
            ' Picks up configuration from the configuration file.
            Dim wcfClient As New SampleDuplexHelloClient(New InstanceContext(Me), "WSDualHttpBinding_SampleDuplexHello")
            Try
                Console.ForegroundColor = ConsoleColor.White
                Console.WriteLine("Enter a greeting to send and press ENTER: ")
                Console.Write(">>> ")
                Console.ForegroundColor = ConsoleColor.Green
                Dim greeting As String = Console.ReadLine()
                Console.ForegroundColor = ConsoleColor.White
                Console.WriteLine("Called service with: " & Constants.vbCrLf & Constants.vbTab & greeting)
                wcfClient.Hello(greeting)
                Console.WriteLine("Execution passes service call and moves to the WaitHandle.")
                Me.waitHandle.WaitOne()
                Console.ForegroundColor = ConsoleColor.Blue
                Console.WriteLine("Set was called.")
                Console.Write("Press ")
                Console.ForegroundColor = ConsoleColor.Red
                Console.Write("ENTER")
                Console.ForegroundColor = ConsoleColor.Blue
                Console.Write(" to exit...")
                Console.ReadLine()
            Catch timeProblem As TimeoutException
                Console.WriteLine("The service operation timed out. " & timeProblem.Message)
                Console.ReadLine()
            Catch commProblem As CommunicationException
                Console.WriteLine("There was a communication problem. " & commProblem.Message)
                Console.ReadLine()
            End Try
        End Sub
        Public Shared Sub Main()
            Dim client As New Client()
            client.Run()
        End Sub

        Public Sub Reply(ByVal response As String) Implements SampleDuplexHelloCallback.Reply
            Console.WriteLine("Received output.")
            Console.WriteLine(Constants.vbCrLf & Constants.vbTab & response)
            Me.waitHandle.Set()
        End Sub
    End Class
End Namespace

使用 CallbackDebugBehavior 启用托管异常信息流

可以在客户端回调对象中启用托管异常信息流，使异常信息流回到服务以便进行调试，方法是以编程方式或从应用程序配置文件中将 IncludeExceptionDetailInFaults 属性设置为 true。

将托管异常信息返回到服务可能存在安全风险，因为异常详细信息会公开与内部客户端实现有关的信息，而未经授权的服务可能会使用这些信息。此外，虽然 CallbackDebugBehavior 属性也可以通过编程方式进行设置，但在部署时容易忘记禁用 IncludeExceptionDetailInFaults。

由于涉及到一些安全问题，因此强烈建议您：

使用应用程序配置文件将 IncludeExceptionDetailInFaults 属性的值设置为 true。
仅在受控调试方案中才能这样做。

下面的代码示例演示一个客户端配置文件，该文件指示 WCF 从 SOAP 消息中的客户端回调对象返回托管异常信息。

  <client>
      <endpoint 
        address="http://localhost:8080/DuplexHello" 
        binding="wsDualHttpBinding"
        bindingConfiguration="WSDualHttpBinding_SampleDuplexHello"
        contract="SampleDuplexHello" 
        name="WSDualHttpBinding_SampleDuplexHello"
        behaviorConfiguration="enableCallbackDebug">
      </endpoint>
  </client>
<behaviors>
  <endpointBehaviors>
    <behavior name="enableCallbackDebug">
      <callbackDebug includeExceptionDetailInFaults="true"/>
    </behavior>
  </endpointBehaviors>
</behaviors>

使用 ClientViaBehavior 行为

可以使用 ClientViaBehavior 行为指定应为其创建传输通道的统一资源标识符。当直接网络目标不是消息的预期处理者时，可使用此行为。当调用应用程序不需要知道最终目标时，或者当目标 Via 标头不是地址时，使用此行为可启用多跃点对话。

请参阅

指定服务运行时行为

指定客户端运行时行为

使用 CallbackBehaviorAttribute

使用 CallbackDebugBehavior 启用托管异常信息流

使用 ClientViaBehavior 行为

请参阅

其他资源