在WCF Rest Service中处理404

<service-response>
   <error>The url requested does not exist</error>
</service-response>

 public class WebHttpExceptionBehaviorElement : BehaviorExtensionElement
 {
    ///  
    /// Get the type of behavior to attach to the endpoint  
    ///  
    public override Type BehaviorType
    {
        get
        {
            return typeof(WebHttpExceptionBehavior);
        }
    }
    ///  
    /// Create the custom behavior  
    ///  
    protected override object CreateBehavior()
    {
        return new WebHttpExceptionBehavior();
    }  
 }

<extensions>
  <behaviorExtensions>
    <add name="customError" type="Service.WebHttpExceptionBehaviorElement, Service"/>
  </behaviorExtensions>
</extensions>

<customError /> 

首先，创建一个自定义行为，该行为子类化WebHttpBehavior-在这里，您将删除默认的Unhandled Dispatch Operation处理程序，并附加您自己的：

public class WebHttpBehaviorEx : WebHttpBehavior
{
    public override void ApplyDispatchBehavior(ServiceEndpoint endpoint, EndpointDispatcher endpointDispatcher)
    {
        base.ApplyDispatchBehavior(endpoint, endpointDispatcher);
        endpointDispatcher.DispatchRuntime.Operations.Remove(endpointDispatcher.DispatchRuntime.UnhandledDispatchOperation);
        endpointDispatcher.DispatchRuntime.UnhandledDispatchOperation = new DispatchOperation(endpointDispatcher.DispatchRuntime, "*", "*", "*");
        endpointDispatcher.DispatchRuntime.UnhandledDispatchOperation.DeserializeRequest = false;
        endpointDispatcher.DispatchRuntime.UnhandledDispatchOperation.SerializeReply = false;
        endpointDispatcher.DispatchRuntime.UnhandledDispatchOperation.Invoker = new UnknownOperationInvoker();
    }
}

然后。制作未知的操作处理程序。这个类将处理未知的操作请求，并生成一个"Message"作为响应。我展示了如何创建纯文本消息。为您的目的修改它应该是相当直接的：

internal class UnknownOperationInvoker : IOperationInvoker
{
    public object[] AllocateInputs()
    {
        return new object[1];
    }

    private Message CreateTextMessage(string message)
    {
        Message result = Message.CreateMessage(MessageVersion.None, null, new HelpPageGenerator.TextBodyWriter(message));
        result.Properties["WebBodyFormatMessageProperty"] = new WebBodyFormatMessageProperty(WebContentFormat.Raw);
        WebOperationContext.Current.OutgoingResponse.ContentType = "text/html";
        return result;
    }
    public object Invoke(object instance, object[] inputs, out object[] outputs)
    {
        // Code HERE
                StringBuilder builder = new System.Text.StringBuilder();
                builder.Append("...");
                Message result = CreateTextMessage(builder.ToString());
                return result;
    }
    public System.IAsyncResult InvokeBegin(object instance, object[] inputs, System.AsyncCallback callback, object state)
    {
        throw new System.NotImplementedException();
    }
    public object InvokeEnd(object instance, out object[] outputs, System.IAsyncResult result)
    {
        throw new System.NotImplementedException();
    }
    public bool IsSynchronous
    {
        get { return true; }
    }
}

此时，您必须将新行为与您的服务相关联。

有几种方法可以做到这一点，所以如果你还不知道，就问问吧，我很乐意进一步阐述。

我也遇到过类似的问题，而另一个答案确实导致了我最终的成功，这不是最清楚的答案。以下是我解决这个问题的方法。

我的项目设置是作为IIS中的svc托管的WCF服务。我无法使用配置路由来添加行为，因为由于持续集成，我的程序集版本每次签入都会更改。

为了克服这个障碍，我创建了一个自定义ServiceHostFactory：

using System.ServiceModel;
using System.ServiceModel.Activation;
namespace your.namespace.here
{
    public class CustomServiceHostFactory : WebServiceHostFactory
    {
        protected override ServiceHost CreateServiceHost(Type serviceType, Uri[] baseAddresses)
        {
            ServiceHost host = base.CreateServiceHost(serviceType, baseAddresses);
            //note: these endpoints will not exist yet, if you are relying on the svc system to generate your endpoints for you
            // calling host.AddDefaultEndpoints provides you the endpoints you need to add the behavior we need.
            var endpoints = host.AddDefaultEndpoints();
            foreach (var endpoint in endpoints)
            {
                endpoint.Behaviors.Add(new WcfUnkownUriBehavior());
            }
            return host;
        }
    }
}

正如您在上面看到的，我们正在添加一个新的行为：WcfUnknownRiBehavior。这种新的风俗行为的灵魂职责是取代未知的破坏者。下面是实现：

using System.ServiceModel.Dispatcher;
using System.ServiceModel.Channels;
using System.ServiceModel.Web;
namespace your.namespace.here
{
    public class UnknownUriDispatcher : IOperationInvoker
    {
        public object[] AllocateInputs()
        {
            //no inputs are really going to come in,
            //but we want to provide an array anyways
            return new object[1]; 
        }
        public object Invoke(object instance, object[] inputs, out object[] outputs)
        {
            var responeObject = new YourResponseObject()
            {
                Message = "Invalid Uri",
                Code = "Error",
            };
            Message result = Message.CreateMessage(MessageVersion.None, null, responeObject);
            WebOperationContext.Current.OutgoingResponse.ContentType = "text/html";
            outputs = new object[1]{responeObject};
            return result;
        }
        public System.IAsyncResult InvokeBegin(object instance, object[] inputs, System.AsyncCallback callback, object state)
        {
            throw new System.NotImplementedException();
        }
        public object InvokeEnd(object instance, out object[] outputs, System.IAsyncResult result)
        {
            throw new System.NotImplementedException();
        }
        public bool IsSynchronous
        {
            get { return true; }
        }
    }
}

一旦指定了这些对象，现在就可以在svc的"标记"中使用新工厂：

<%@ ServiceHost Language="C#" Debug="true" Service="your.service.namespace.here" CodeBehind="myservice.svc.cs"
                Factory="your.namespace.here.CustomServiceHostFactory" %>

应该就是这样。只要你的对象"YourResponseObject"可以序列化，它的序列化表示就会被发送回客户端。