WCF 客户端，XML 命名空间前缀导致空对象

Question

我已经创建了一个 WCF 服务 (.NET 4.6.2)，并且第三方已经创建了客户端。

我无法控制客户端，也无法让第三方更改任何内容，因此任何更改都将仅在服务器端进行。

我已将代码最小化并匿名化到最低限度，希望能用尽可能少的代码来演示问题。如果我犯了任何错误或者您需要任何进一步的详细信息，我将相应地更改详细信息。

总结

客户端能够调用服务，解析器能够正确识别来自 SOAP Action 的代码中的方法，但是传入的任何对象始终为 null。我能够使用断点捕获请求，并看到对象在运行时为空。

我发现问题主要是由客户端传递的 XML 名称空间前缀引起的。

我能够拦截传入的原始消息，并且我可以准确地看到客户端发送的内容。

我能够操纵这些传入消息进行实验，然后 post 将消息的修改版本发送到服务，以使用基于通用浏览器的客户端测试结果。

示例数据协定：-

[DataContract(Namespace = "http://mycompanyname.co.uk")]
public class SomeObject
{
    [DataMember]
    public string SomeField { get; set; }
}

示例服务合同：-

[ServiceContract(Namespace = "http://mycompanyname.co.uk")]
public interface IIncoming
{
    [OperationContract]
    XmlElement MyAction(SomeObject someObject);
}

实施先前定义的服务契约的示例 WCF 服务：-

[ServiceBehavior(Namespace = "http://mycompanyname.co.uk")]
public class Incoming : IIncoming
{
    public XmlElement MyAction(SomeObject someObject)
    {
        XmlDocument response = new XmlDocument();
        response.LoadXml("<Response>OK</Response>");
        return response.DocumentElement;
    }
}

这是第 3 方 post 向服务发送的内容：-

/*3rd party original*/
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">
    <soapenv:Body>
        <ns1:MyAction xmlns:ns1="http://mycompanyname.co.uk">
            <someObject xmlns="">
                <SomeField>Blah</SomeField>
            </someObject>
        </ns1:MyAction>
    </soapenv:Body>
</soapenv:Envelope>

断点代码，我可以看到上面的结果是调用了 MyAction，但是 MyObject 是 null

我修改了 SOAP 消息以删除空白的 xmlns，但 someObject 仍然为 null

/*blank xmlns removed*/
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">
    <soapenv:Body>
        <ns1:MyAction xmlns:ns1="http://mycompanyname.co.uk">
            <someObject>
                <SomeField>Blah</SomeField>
            </someObject>
        </ns1:MyAction>
    </soapenv:Body>
</soapenv:Envelope>

我修改了 SOAP 消息以删除 ns1 前缀，但 someObject 仍然为 null

/*ns1 removed*/
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">
    <soapenv:Body>
        <MyAction xmlns="http://mycompanyname.co.uk">
            <someObject xmlns="">
                <SomeField>Blah</SomeField>
            </someObject>
        </MyAction>
    </soapenv:Body>
</soapenv:Envelope>

现在，如果我同时删除 ns1 前缀和空白 xmlns，则 someObject 会按预期正确填充。这解决了一切。唯一的问题是，我无法让客户进行此更改。

/*both removed - works*/
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">
    <soapenv:Body>
        <MyAction xmlns="http://mycompanyname.co.uk">
            <someObject>
                <SomeField>Blah</SomeField>
            </someObject>
        </MyAction>
    </soapenv:Body>
</soapenv:Envelope>

首先，为什么会这样？正如我在 XML 中所理解的那样，前缀实际上与确定对象无关，因此 <ns1:Something> 应该与 <ns2:Something> 或 <Something> 是同一个对象然而，WCF 解析器确定 <ns1:Something> 不是 <Something>

如何在服务器端解决这个问题，最好是从 WCF 服务内部解决？我在想是否有一种方法可以在 WCF 服务中解析消息之前捕获消息并预先去除 ns1: 和空白 xmlns？

非常感谢

编辑

这是一个示例，您可以 copy/paste 准确重现问题：-

创建 WCF 服务应用程序 (.NET Framework 4.6.2)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.Text;
using System.Xml;

namespace GenericIncoming
{
    [ServiceContract(Namespace = "http://mycompanyname.co.uk")]
    public interface IIncoming
    {
        [OperationContract]
        XmlElement MyAction(SomeObject someObject);
    }

    [DataContract(Namespace ="")]
    public class SomeObject
    {
        [DataMember]
        public string SomeField { get; set; }
    }
}



using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.Text;
using System.Xml;

namespace GenericIncoming
{
    [ServiceBehavior(Namespace = "http://mycompanyname.co.uk")]
    public class Incoming : IIncoming
    {
        public XmlElement MyAction(SomeObject someObject)
        {
            XmlDocument response = new XmlDocument();
            if (someObject != null)
            {
                response.LoadXml("<Response>OK</Response>");
            }
            else
            {
                response.LoadXml("<Response>NULL</Response>");
            }
            return response.DocumentElement;
        }
    }
}

运行您的 WCF 服务和 POST 此消息到该服务，您将收到 "OK" 响应

<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">
    <s:Body>
        <MyAction xmlns="http://mycompanyname.co.uk">
            <someObject>
                <SomeField>Blah</SomeField>
            </someObject>
        </MyAction>
    </s:Body>
</s:Envelope>

现在如果你添加 ns1 前缀，就像第 3 方发送给我的那样，那么响应是 "NULL" 这意味着 WCF 中的对象是空的，因为解析器无法处理XML

<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">
    <s:Body>
        <ns1:MyAction xmlns:ns1="http://mycompanyname.co.uk">
            <someObject>
                <SomeField>Blah</SomeField>
            </someObject>
        </ns1:MyAction>
    </s:Body>
</s:Envelope>

这是我无法解决的第一个问题

Answer 1

尝试以下操作：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml;
using System.Xml.Serialization;
using System.IO;

namespace ConsoleApplication1
{
    public class Program
    {
        const string FILENAME = @"c:\temp\test.xml";
        static void Main(string[] args)
        {
            string response = File.ReadAllText(FILENAME);
            StringReader sReader = new StringReader(response);

            XmlSerializer serializer = new XmlSerializer(typeof(Envelope));
            Envelope envelope = (Envelope)serializer.Deserialize(sReader);

        }
    }
    [XmlRoot(ElementName = "Envelope", Namespace = "http://schemas.xmlsoap.org/soap/envelope/")]
    public class Envelope
    {
        [XmlElement(ElementName = "Body", Namespace = "http://schemas.xmlsoap.org/soap/envelope/")]
        public Body body { get;set;}
    }
    [XmlRoot(ElementName = "Body", Namespace = "http://schemas.xmlsoap.org/soap/envelope/")]
    public class Body
    {
        [XmlElement(ElementName = "MyAction", Namespace = "http://mycompanyname.co.uk")]
        public MyAction myAction { get; set; }
    }
    [XmlRoot(ElementName = "MyAction", Namespace = "http://mycompanyname.co.uk")]
    public class MyAction
    {
        [XmlElement(ElementName = "someObject", Namespace = "")]
        public SomeObject someObject { get; set; }
    }
    [XmlRoot(ElementName = "someObject", Namespace = "")]
    public class SomeObject
    {
        public string SomeField { get; set; }
    }


}

Answer 2

我投入了大量时间寻找简单的解决方案，但似乎不存在。

为了解决这个问题，我最终研究了 MessageInspectors，它允许在原始 SOAP 消息被 WCF 服务处理之前查看和编辑它们。

创建一个实现 IDispatchMessageInspector 的 class。这是实际过滤发生的地方

public class CorrectorInspector : IDispatchMessageInspector
{
    public object AfterReceiveRequest(ref Message request, IClientChannel channel, InstanceContext instanceContext)
    {
        request = FilterMessage(request);
        return null;
    }

    public void BeforeSendReply(ref Message reply, object correlationState)
    {
        return;
    }

    private Message FilterMessage(Message originalMessage)
    {
        MemoryStream memoryStream = new MemoryStream();
        XmlWriter xmlWriter = XmlWriter.Create(memoryStream);
        originalMessage.WriteMessage(xmlWriter);
        xmlWriter.Flush();
        string body = Encoding.UTF8.GetString(memoryStream.ToArray());
        xmlWriter.Close();

        //Remove the ns1 prefix
        body = body.Replace("ns1:", "");
        body = body.Replace(":ns1", "");
        //remove the blank namespace 
        body = body.Replace(" xmlns=\"\"","");

        memoryStream = new MemoryStream(Encoding.UTF8.GetBytes(body));
        XmlDictionaryReader xmlDictionaryReader = XmlDictionaryReader.CreateTextReader(memoryStream, new XmlDictionaryReaderQuotas());
        Message newMessage = Message.CreateMessage(xmlDictionaryReader, int.MaxValue, originalMessage.Version);
        newMessage.Properties.CopyProperties(originalMessage.Properties);
        return newMessage;
    }
}

创建一个实现 IEndpointBehavior

的 class

public class CorrectorBehavior : IEndpointBehavior
{
    public void AddBindingParameters(ServiceEndpoint endpoint, BindingParameterCollection bindingParameters)
    {
        return;
    }

    public void ApplyClientBehavior(ServiceEndpoint endpoint, ClientRuntime clientRuntime)
    {
        return;
    }

    public void ApplyDispatchBehavior(ServiceEndpoint endpoint, EndpointDispatcher endpointDispatcher)
    {
        CorrectorInspector inspector = new CorrectorInspector();
        endpointDispatcher.DispatchRuntime.MessageInspectors.Add(inspector);
    }

    public void Validate(ServiceEndpoint endpoint)
    {
        return;
    }
}

创建一个实现 BehaviorExtensionElement

的 class

public class CorrectorBehaviourExtensionElement : BehaviorExtensionElement
{
    public override Type BehaviorType
    {
        get
        {
            return typeof(CorrectorBehavior);
        }
    }

    protected override object CreateBehavior()
    {
        return new CorrectorBehavior();
    }
}

在web.config中，我们需要定义behaviorExtension，serviceBehavior，然后我们需要针对服务绑定指定我们新创建的行为

 <system.serviceModel>
    <services>
      <service name="GenericIncoming.Incoming">
        <endpoint address="" binding="basicHttpBinding" contract="GenericIncoming.IIncoming" behaviorConfiguration="correctorBehavior" />
      </service>
    </services>    
    <behaviors>
      <serviceBehaviors>
        <behavior>
          <serviceMetadata httpGetEnabled="true" httpsGetEnabled="true"/>
          <serviceDebug includeExceptionDetailInFaults="false"/>
        </behavior>
      </serviceBehaviors>
      <endpointBehaviors>
        <behavior name="correctorBehavior">
          <serviceFilter />
        </behavior>
      </endpointBehaviors>      
    </behaviors>
    <extensions>
      <behaviorExtensions>
        <add name="serviceFilter" type="GenericIncoming.CorrectorBehaviourExtensionElement, GenericIncoming, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" />
      </behaviorExtensions>
    </extensions>
    <protocolMapping>
        <add binding="basicHttpsBinding" scheme="https" />
    </protocolMapping>    
    <serviceHostingEnvironment aspNetCompatibilityEnabled="true" multipleSiteBindingsEnabled="true" />
  </system.serviceModel>

这是一个相当重量级的解决方案，但它确实完美地工作，学习这个功能肯定对以后的项目有用。

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