c# – WCF：在IErrorHandler中提供通用的FaultException

public void ProvideFault(Exception error,MessageVersion version,ref Message fault)
{
    if (!(error is FaultException))
    {
        FaultException faultException = FaultExceptionFactory.CreateFaultException(error);
        MessageFault messageFault = faultException.CreateMessageFault();
        fault = Message.CreateMessage(version,messageFault,faultException.Action);
    }
}

BusinessRuleFaultExceptionType businessRuleFaultException = new BusinessRuleFaultExceptionType();
BusinessRuleFaultException.Code = exception.Code.ToString();
BusinessRuleFaultException.Reason = exception.Message;
return new FaultException<BusinessRuleFaultExceptionType>(
    businessRuleFaultException,exception.Message,new FaultCode(exception.Code.ToString())
);

<wsdl:operation name="MyMethod">
<wsdl:fault wsaw:Action="http://myNamespace/MyMethodBusinessRuleFaultExceptionTypeFault" name="BusinessRuleFaultExceptionTypeFault" message="tns:..."/>

<s:Fault>
    <faultcode xmlns="">s:-100</faultcode>
    <faultstring xml:lang="en-US" xmlns="">xxx</faultstring>
    <detail xmlns="">
        <BusinessRuleFaultExceptionType xmlns="http://myNamespace/Services" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
            <Code xmlns="http://myNamespace/Entitites">-100</Code>
            <Reason xmlns="http://myNamespace/Entitites">xxx</Reason>
        </BusinessRuleFaultExceptionType>
    </detail>
</s:Fault>

<s:Fault>
    <faultcode xmlns="">s:-100</faultcode>
    <faultstring xml:lang="en-US" xmlns="">xxx</faultstring>
    <detail xmlns="">
        <BusinessRuleFaultExceptionType xmlns="http://schemas.datacontract.org/2004/07/My.Dot.Net.Namespace" xmlns:i="http://www.w3.org/2001/XMLSchema-instance">
            <codeField>-100</codeField>
            <reasonField>xxx</reasonField>
        </BusinessRuleFaultExceptionType>
    </detail>
</s:Fault>

<s:Fault>
    <faultcode xmlns="">s:-100</faultcode>
    <faultstring xml:lang="en-US" xmlns="">xxx</faultstring>
    <detail xmlns="">
        <BusinessRuleFaultExceptionType xmlns="http://myNamespace/Services" xmlns:i="http://www.w3.org/2001/XMLSchema-instance">
            <Code>-100</Code>
            <Reason>xxx</Reason>
        </BusinessRuleFaultExceptionType>
    </detail>
</s:Fault>

<s:Fault>
    <faultcode xmlns="">s:-100</faultcode>
    <faultstring xml:lang="en-US" xmlns="">xxx</faultstring>
    <detail xmlns="">
        <BusinessRuleFaultExceptionType xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
            <Code xmlns="http://myNamespace/Entitites">-100</Code>
            <Reason xmlns="http://myNamespace/Entitites">xxx</Reason>
        </BusinessRuleFaultExceptionType>
    </detail>
</s:Fault>

我对WSCF.blue没有任何经验,因此我尝试使用标准WCF客户端和服务器创建示例应用程序来演示工作方案.也许它可以帮助您找到缺少的连接,使您的方案工作.

我使用了BusinessRuleFaultExceptionType和Code和Reason属性. BusinessRuleFaultExceptionType是WCF错误契约.

我有点懒,并在一个控制台应用程序中实现了所有代码. Wcf客户端使用与Wcf服务相同的Datacontracts和ICalculator接口.对不起代码.这将是一个很长的帖子.

首先是Datacontracts和服务接口

using System;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.ServiceModel.Channels;
using System.ServiceModel.Description;
using System.ServiceModel.Dispatcher;

[ServiceContract(Namespace = "http://UE.ServiceModel.Samples")]
public interface ICalculator
{
    [OperationContract(IsOneWay = false)]
    [FaultContract(typeof(BusinessRuleFaultExceptionType))]
    double Add(double n1,double n2);

    [OperationContract(IsOneWay = false)]
    [FaultContract(typeof(BusinessRuleFaultExceptionType))]
    double Subtract(double n1,double n2);

    [OperationContract(IsOneWay = false)]
    [FaultContract(typeof(BusinessRuleFaultExceptionType))]
    double Multiply(double n1,double n2);

    [OperationContract(IsOneWay = false)]
    [FaultContract(typeof(BusinessRuleFaultExceptionType))]
    double Divide(double n1,double n2);
}

/// <summary>
/// General fault structure. 
/// </summary>
[DataContract(Namespace = "http://someurl.temp")]
public sealed class BusinessRuleFaultExceptionType
{
    [DataMember]
    public int Code { get; set; }

    [DataMember]
    public string Reason { get; set; }
}

现在,服务实现：

[ErrorBehavior(typeof(MyErrorHandler))]
public class CalculatorService : ICalculator
{
    public double Add(double n1,double n2)
    {
        double result = n1 + n2;
        Console.WriteLine("Received Add({0},{1})",n1,n2);
        Console.WriteLine("Return: {0}",result);
        throw new ArgumentException("My exception");
        return result;
    }

    public double Subtract(double n1,double n2)
    {
        double result = n1 - n2;
        Console.WriteLine("Received Subtract({0},result);
        return result;
    }

    public double Multiply(double n1,double n2)
    {
        double result = n1 * n2;
        Console.WriteLine("Received Multiply({0},result);
        return result;
    }

    public double Divide(double n1,double n2)
    {
        double result = n1 / n2;
        Console.WriteLine("Received Divide({0},result);
        return result;
    }
}

和客户端实施：

public class Client : ClientBase<ICalculator>,ICalculator
{

    public double Add(double n1,double n2)
    {
        try
        {
            return base.Channel.Add(n1,n2);
        }
        catch (FaultException<BusinessRuleFaultExceptionType> ex)
        {
            Console.WriteLine("This is my Code: {0}. This is the reason: {1}",ex.Detail.Code,ex.Detail.Reason);
        }
        catch (Exception ex)
        {
            throw;
        }
        return 0;
    }

    public double Subtract(double n1,double n2)
    {
        throw new NotImplementedException();
    }

    public double Multiply(double n1,double n2)
    {
        throw new NotImplementedException();
    }

    public double Divide(double n1,double n2)
    {
        throw new NotImplementedException();
    }
}

主程序来演示这个例子

internal class Program
{
    private static void Main(string[] args)
    {
        ServiceHost myServiceHost = new ServiceHost(typeof(CalculatorService));

        // Open the ServiceHostBase to create listeners and start listening for messages.
        myServiceHost.Open();

        // The service can now be accessed.
        Console.WriteLine("The service is ready.");
        Console.WriteLine("Press <ENTER> to terminate service.");
        Console.WriteLine();

        Console.ReadLine();

        Console.WriteLine("Sending data from client to service.");
        Client c = new Client();
        var res = c.Add(1,2);

        Console.ReadLine();
    }

}

错误处理的实现：

/// <summary>
/// Helper class for exception repackaging.
/// </summary>
internal class MyExceptionHandler
{
    /// <summary>
    /// Handles thrown exception into internal exceptions that are being sent over to client.
    /// </summary>
    /// <param name="error">Exception thrown.</param>
    /// <returns>Repackaged exception.</returns>
    internal static Exception HandleError(Exception error)
    {
        // could do something here.
        return error;
    }
}

#region Behaviour
/// <summary>
/// Control the fault message returned to the caller and optionally perform custom error processing such as logging.
/// </summary>
public sealed class MyErrorHandler : IErrorHandler
{
    /// <summary>
    /// Provide a fault. The Message fault parameter can be replaced,or set to null to suppress reporting a fault.
    /// </summary>
    /// <param name="error">The <see cref="Exception"/> object thrown in the course of the service operation.</param>
    /// <param name="version">The SOAP version of the message.</param>
    /// <param name="fault">The <see cref="System.ServiceModel.Channels.Message"/> object that is returned to the client,or service,in the duplex case.</param>
    public void ProvideFault(Exception error,ref Message fault)
    {
        //If it's a FaultException already,then we have nothing to do
        if (error is FaultException)
            return;

        error = MyExceptionHandler.HandleError(error);

        var serviceDebug = OperationContext.Current.EndpointDispatcher.ChannelDispatcher.IncludeExceptionDetailInFaults;

        BusinessRuleFaultExceptionType f = new BusinessRuleFaultExceptionType
        {
            Code = -100,Reason = "xxx"
        };

        FaultException<BusinessRuleFaultExceptionType> faultException = new FaultException<BusinessRuleFaultExceptionType>(f,error.Message);
        MessageFault faultMessage = faultException.CreateMessageFault();
        fault = Message.CreateMessage(version,faultMessage,faultException.Action);
    }

    /// <summary>
    /// Enables error-related processing and returns a value that indicates whether the dispatcher aborts the session and the instance context in certain cases.
    /// </summary>
    /// <param name="error">The exception thrown during processing.</param>
    /// <returns>true if Windows Communication Foundation (WCF) should not abort the session (if there is one) and instance context if the instance context is not Single; otherwise,false. The default is false.</returns>
    public bool HandleError(Exception error)
    {
        // could use some logger like Nlog but as an example it will do.
        Console.WriteLine("Error occured. {0}",error);

        return true;
    }
}

/// <summary>
/// This attribute is used to install a custom error handler for a service
/// </summary>
public sealed class ErrorBehaviorAttribute : Attribute,IServiceBehavior
{
    /// <summary>
    /// Type of component to which this error handled should be bound
    /// </summary>
    private readonly Type errorHandlerType;

    /// <summary>
    /// Initializes a new instance of the ErrorBehaviorAttribute class.
    /// </summary>
    /// <param name="errorHandlerType">Type of component to which this error handled should be bound</param>
    public ErrorBehaviorAttribute(Type errorHandlerType)
    {
        this.errorHandlerType = errorHandlerType;
    }

    /// <summary>
    /// Type of component to which this error handled should be bound
    /// </summary>
    public Type ErrorHandlerType
    {
        get { return errorHandlerType; }
    }

    /// <summary>
    /// Provides the ability to inspect the service host and the service description to confirm that the service can run successfully.
    /// </summary>
    /// <param name="description">
    /// <para>Type: <see cref="System.ServiceModel.Description.ServiceDescription"/></para>
    /// <para>The service description.</para>
    /// </param>
    /// <param name="serviceHostBase">
    /// <para>Type: <see cref="System.ServiceModel.ServiceHostBase"/></para>
    /// <para>The service host that is currently being constructed.</para>
    /// </param>
    void IServiceBehavior.Validate(ServiceDescription description,ServiceHostBase serviceHostBase)
    {
    }

    /// <summary>
    /// Provides the ability to pass custom data to binding elements to support the contract implementation.
    /// </summary>
    /// <param name="description">
    /// <para>Type: <see cref="System.ServiceModel.Description.ServiceDescription"/></para>
    /// <para>The service description.</para>
    /// </param>
    /// <param name="serviceHostBase">
    /// <para>Type: <see cref="System.ServiceModel.ServiceHostBase"/></para>
    /// <para>The host of the service.</para>
    /// </param>
    /// <param name="endpoints">
    /// <para>Type: <see cref="System.Collections.ObjectModel.Collection&lt;ServiceEndpoint&gt;"/></para>
    /// <para>The service endpoints.</para>
    /// </param>
    /// <param name="parameters">
    /// <para>Type: <see cref="System.ServiceModel.Channels.BindingParameterCollection"/></para>
    /// <para>Custom objects to which binding elements have access.</para>
    /// </param>
    void IServiceBehavior.AddBindingParameters(ServiceDescription description,ServiceHostBase serviceHostBase,System.Collections.ObjectModel.Collection<ServiceEndpoint> endpoints,BindingParameterCollection parameters)
    {
    }

    /// <summary>
    /// Provides the ability to change run-time property values or insert custom extension objects such as error handlers,message or parameter interceptors,security extensions,and other custom extension objects.
    /// </summary>
    /// <param name="description">
    /// <para>Type: <see cref="System.ServiceModel.Description.ServiceDescription"/></para>
    /// <para>The service description.</para>
    /// </param>
    /// <param name="serviceHostBase">
    /// <para>Type: <see cref="System.ServiceModel.ServiceHostBase"/></para>
    /// <para>The host that is currently being built.</para>
    /// </param>
    void IServiceBehavior.ApplyDispatchBehavior(ServiceDescription description,ServiceHostBase serviceHostBase)
    {
        IErrorHandler errorHandler;

        try
        {
            errorHandler = (IErrorHandler)Activator.CreateInstance(errorHandlerType);
        }
        catch (MissingMethodException e)
        {
            throw new ArgumentException("The errorHandlerType specified in the ErrorBehaviorAttribute constructor must have a public empty constructor.",e);
        }
        catch (InvalidCastException e)
        {
            throw new ArgumentException("The errorHandlerType specified in the ErrorBehaviorAttribute constructor must implement System.ServiceModel.Dispatcher.IErrorHandler.",e);
        }

        foreach (ChannelDispatcherBase channelDispatcherBase in serviceHostBase.ChannelDispatchers)
        {
            ChannelDispatcher channelDispatcher = channelDispatcherBase as ChannelDispatcher;
            channelDispatcher.ErrorHandlers.Add(errorHandler);
        }
    }
}

#endregion

我的控制台应用程序的app.config：

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <startup>
    <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
  </startup>
  <system.serviceModel>
    <client>
      <endpoint address="http://localhost:12345/service/calc" binding="basicHttpBinding" contract="ConsoleApplication2.ICalculator" >
      </endpoint>
    </client>
    <services>
      <service name="ConsoleApplication2.CalculatorService" behaviorConfiguration="service">
        <endpoint address="http://localhost:12345/service/calc" binding="basicHttpBinding" contract="ConsoleApplication2.ICalculator" >
        </endpoint>
        <host>
          <baseAddresses>
            <add baseAddress="http://localhost:12345/service/calc" />
          </baseAddresses>
        </host>
      </service>

    </services>
    <behaviors>
      <serviceBehaviors>
        <behavior name="service">
          <serviceMetadata httpGetEnabled="true" />
        </behavior>
      </serviceBehaviors>
    </behaviors>
  </system.serviceModel>
</configuration>

我使用WCF测试客户端发送此请求：

<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">
  <s:Header>
    <Action s:mustUnderstand="1" xmlns="http://schemas.microsoft.com/ws/2005/05/addressing/none">http://UE.ServiceModel.Samples/ICalculator/Add</Action>
  </s:Header>
  <s:Body>
    <Add xmlns="http://UE.ServiceModel.Samples">
      <n1>0</n1>
      <n2>1</n2>
    </Add>
  </s:Body>
</s:Envelope>

得到了这个回应：

<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">
  <s:Header />
  <s:Body>
    <s:Fault>
      <faultcode>s:Client</faultcode>
      <faultstring xml:lang="sk-SK">My exception</faultstring>
      <detail>
        <BusinessRuleFaultExceptionType xmlns="http://someurl.temp" xmlns:i="http://www.w3.org/2001/XMLSchema-instance">
          <Code>-100</Code>
          <Reason>xxx</Reason>
        </BusinessRuleFaultExceptionType>
      </detail>
    </s:Fault>
  </s:Body>
</s:Envelope>

我打电话的时候

Client c = new Client();
var res = c.Add(1,2);

我发现了FaultException< BusinessRuleFaultExceptionType>我记录到控制台的ex

Console.WriteLine("This is my Code: {0}. This is the reason: {1}",ex.Detail.Reason);

编辑：我在BusinessRuleFaultExceptionType中更改了名称空间,并将解决方案设置为使用[XmlSerializerFormat(SupportFaults = true)].

更改了界面,数据交换和服务实现：

[ServiceContract(Namespace = "http://UE.ServiceModel.Samples")]
[XmlSerializerFormat(SupportFaults = true)]
public interface ICalculator
{
    [OperationContract(IsOneWay = false)]
    [FaultContract(typeof(BusinessRuleFaultExceptionType))]
    double Add(double n1,double n2);
}

/// <summary>
/// General fault structure. 
/// </summary>
[DataContract(Name = "BusinessRuleFaultExceptionType",Namespace = "http://someurl.temp")]
[XmlType("BusinessRuleFaultExceptionType",Namespace = "http://someurl.temp")]
public sealed class BusinessRuleFaultExceptionType
{
    //[DataMember]
    [XmlElement(IsNullable = false,Namespace = "http://namespaces2.url")]
    public int Code { get; set; }

    [XmlElement(IsNullable = false,Namespace = "http://namespaces2.url")]
    public string Reason { get; set; }
}

[ErrorBehavior(typeof(MyErrorHandler))]
public class CalculatorService : ICalculator
{
    public double Add(double n1,result);

        throw new FaultException<BusinessRuleFaultExceptionType>(new BusinessRuleFaultExceptionType()
        {
            Code = -100,Reason = "xxx"
        });
        //throw new ArgumentException("My exception");
        return result;
    }

    public double Subtract(double n1,result);
        return result;
    }
}

我找到了一篇关于there are problems在IErrorHandler中使用XmlSerializer的原因的文章.因此,我已经更改了服务实现,以在方法实现中抛出FaultException,并且不依赖于IErrorHandler.

我还发现了另一篇(相对较旧的)文章how to use XmlSerializer in IErroHandler,经过一段时间我甚至可以从IErrorHandler进行序列化.我将trown异常更改回ArgumentException.
以下是更改(我继续前面的示例,因此可能不需要所有代码和属性)：

[DataContract(Name = "BusinessRuleFaultExceptionType",Namespace = "http://someurl.temp")]
[XmlRoot("BusinessRuleFaultExceptionType",Namespace = "http://namespaces2.url")]
    public string Reason { get; set; }
}

public class XmlSerializerMessageFault : MessageFault
{
    FaultCode code;
    FaultReason reason;

    object details;

    public XmlSerializerMessageFault(FaultCode code,FaultReason reason,object details)
    {
        this.details = details;
        this.code = code;
        this.reason = reason;
    }

    public override FaultCode Code
    {
        get { return code; }
    }

    public override bool HasDetail
    {
        get { return (details != null); }
    }

    protected override void OnWriteDetailContents(System.Xml.XmlDictionaryWriter writer)
    {
        var ser = new XmlSerializer(details.GetType());
        ser.Serialize(writer,details);
        writer.Flush();
    }

    public override FaultReason Reason
    {
        get { return reason; }
    }
}

/// <summary>
/// Control the fault message returned to the caller and optionally perform custom error processing such as logging.
/// </summary>
public sealed class MyErrorHandler : IErrorHandler
{
    /// <summary>
    /// Provide a fault. The Message fault parameter can be replaced,ref Message fault)
    {

        BusinessRuleFaultExceptionType f = new BusinessRuleFaultExceptionType
        {
            Code = -100,Reason = "xxx"
        };

        // create a fault message containing our FaultContract object
        FaultException<BusinessRuleFaultExceptionType> faultException = new FaultException<BusinessRuleFaultExceptionType>(f,error.Message);
        MessageFault faultMessage = faultException.CreateMessageFault();

        var msgFault = new XmlSerializerMessageFault(faultMessage.Code,faultMessage.Reason,f);

        fault = Message.CreateMessage(version,msgFault,error);

        return true;
    }
}

在这两种情况下,序列化故障是：

<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">
  <s:Header />
  <s:Body>
    <s:Fault>
      <faultcode>s:Client</faultcode>
      <faultstring xml:lang="sk-SK">My exception</faultstring>
      <detail>
        <BusinessRuleFaultExceptionType xmlns="http://someurl.temp" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
          <Code xmlns="http://namespaces2.url">-100</Code>
          <Reason xmlns="http://namespaces2.url">xxx</Reason>
        </BusinessRuleFaultExceptionType>
      </detail>
    </s:Fault>
  </s:Body>
</s:Envelope>