C# 如何从WCF服务端捕获传入和传出的XML

在我的解决方案中，我有三个项目。一个是WCF服务，另一个是Winforms应用程序，我在其中调用web服务，最后一个是类库，其中类已设计为扩展soap扩展类

我的目标是在从Winforms应用程序调用WCF服务时捕获响应和请求xml。当我试图捕获xml时，出现对象引用未设置错误

这是我的类库源代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Web.Services;
using System.Web.Services.Protocols;
using System.IO;
using System.Net;
using System.Xml;

namespace SoapLogger
{
public class TraceExtension : SoapExtension
{
    private Stream oldStream;
    private Stream newStream;

    private static XmlDocument xmlRequest;
    /// <summary>
    /// Gets the outgoing XML request sent to PayPal
    /// </summary>
    public static XmlDocument XmlRequest
    {
        get { return xmlRequest; }
    }

    private static XmlDocument xmlResponse;
    /// <summary>
    /// Gets the incoming XML response sent from PayPal
    /// </summary>
    public static XmlDocument XmlResponse
    {
        get { return xmlResponse; }
    }

    /// <summary>
    /// Save the Stream representing the SOAP request
    /// or SOAP response into a local memory buffer.
    /// </summary>
    /// <param name="stream">
    /// <returns></returns>
    public override Stream ChainStream(Stream stream)
    {
        oldStream = stream;
        newStream = new MemoryStream();
        return newStream;
    }

    /// <summary>
    /// If the SoapMessageStage is such that the SoapRequest or
    /// SoapResponse is still in the SOAP format to be sent or received,
    /// save it to the xmlRequest or xmlResponse property.
    /// </summary>
    /// <param name="message">
    public override void ProcessMessage(SoapMessage message)
    {
        switch (message.Stage)
        {
            case SoapMessageStage.BeforeSerialize:
                break;
            case SoapMessageStage.AfterSerialize:
                xmlRequest = GetSoapEnvelope(newStream);
                CopyStream(newStream, oldStream);
                break;
            case SoapMessageStage.BeforeDeserialize:
                CopyStream(oldStream, newStream);
                xmlResponse = GetSoapEnvelope(newStream);
                break;
            case SoapMessageStage.AfterDeserialize:
                break;
        }
    }

    /// <summary>
    /// Returns the XML representation of the Soap Envelope in the supplied stream.
    /// Resets the position of stream to zero.
    /// </summary>
    /// <param name="stream">
    /// <returns></returns>
    private XmlDocument GetSoapEnvelope(Stream stream)
    {
        XmlDocument xml = new XmlDocument();
        stream.Position = 0;
        StreamReader reader = new StreamReader(stream);
        xml.LoadXml(reader.ReadToEnd());
        stream.Position = 0;
        return xml;
    }

    /// <summary>
    /// Copies a stream.
    /// </summary>
    /// <param name="from">
    /// <param name="to">
    private void CopyStream(Stream from, Stream to)
    {
        TextReader reader = new StreamReader(from);
        TextWriter writer = new StreamWriter(to);
        writer.WriteLine(reader.ReadToEnd());
        writer.Flush();
    }
    #region NoOp
    /// <summary>
    /// Included only because it must be implemented.
    /// </summary>
    /// <param name="methodInfo">
    /// <param name="attribute">
    /// <returns></returns>
    public override object GetInitializer(LogicalMethodInfo methodInfo,
        SoapExtensionAttribute attribute)
    {
        return null;
    }

    /// <summary>
    /// Included only because it must be implemented.
    /// </summary>
    /// <param name="WebServiceType">
    /// <returns></returns>
    public override object GetInitializer(Type WebServiceType)
    {
        return null;
    }

    /// <summary>
    /// Included only because it must be implemented.
    /// </summary>
    /// <param name="initializer">
    public override void Initialize(object initializer)
    {
    }
    #endregion NoOp
}

这两条线导致对象引用错误

var soapRequest = SoapLogger.TraceExtension.XmlRequest.InnerXml;
var soapResponse = SoapLogger.TraceExtension.XmlResponse.InnerXml;

我只是不明白为什么我会出错

Winforms应用程序有一个

app.config

，我在其中注册类库程序集以捕获xml。这是我的

app.config

详细信息

<?xml version="1.0"?> 
<configuration> 
<system.serviceModel> 
<bindings> 
<basicHttpBinding> 
<binding name="TestServiceSoap"/> </basicHttpBinding> 
</bindings> <client> <endpoint address="http://localhost:6804/Service1.asmx" 
binding="basicHttpBinding" bindingConfiguration="TestServiceSoap" 
contract="ServiceRef.TestServiceSoap" name="TestServiceSoap"/> 
</client> 
</system.serviceModel> 
<system.web> 
<compilation debug="true" targetFramework="4.0" /> 
<webServices> <soapExtensionTypes> 
<add type="SoapLogger.TraceExtension,SoapLogger" priority="1" group="0" /> 
</soapExtensionTypes> </webServices> 
</system.web> 
<startup>
<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/> 
</startup> </configuration>

我犯了什么样的错误还不清楚。我在类库方法中的每个方法上都设置了断点，但是当web服务调用时，类库中没有执行任何方法。我不想使用wireshark、fiddler之类的工具来捕获请求/响应xml，而是想通过编程来完成同样的事情

所以请告诉我我的错误是什么？为什么获取对象引用未设置错误？请看一看我的代码或转到url链接，告诉我我的方法有什么错误

配置
发送/接收一些消息
获取日志查看器并打开跟踪输出
利润
导致此错误的原因是，在访问它们时，xmlRequest/xmlResponse尚未初始化。因此，请尝试检查null，或为它们创建默认实例

从代码中，它们仅在
ProcessMessage（SoapMessage）{}
中初始化，请确保在调用之前调用了该方法

 var soapRequest = SoapLogger.TraceExtension.XmlRequest.InnerXml;
 var soapResponse = SoapLogger.TraceExtension.XmlResponse.InnerXml;

希望这有帮助

编辑：

仔细检查您的代码后，我意识到您编写的扩展（SoapExtension）是针对ASP.NET XML web服务的，它与WCF服务没有任何关系

要检查WCF服务中的请求和应答，可以通过实现System.ServiceModel.dispatcher.IDispatchMessageInspector来扩展服务端的dispatcher

您可以在这里找到示例，我们只需跟踪请求消息即可

OperationContext context = OperationContext.Current;

if (context != null && context.RequestContext != null)

{

Message msg = context.RequestContext.RequestMessage;

string reqXML = msg.ToString();

}

还有另一种查看XML SOAP的方法-。与IDispatchMessageInspector/IClientMessageInspector的主要区别在于它在较低的级别上工作，因此它捕获原始字节内容，包括任何格式错误的xml

为了使用这种方法实现跟踪，您需要将一个标准包装为新的，并将该自定义绑定应用到您的应用程序中的端点

你也可以看到我在我的项目中是如何做到这一点的-
textMessageEncoding、logging、，自定义绑定和。
未找到。u plzz能否将我重定向到有关此主题的正确文章，从中我可以获得完整的工作代码示例，可以在我的pc中运行。感谢使用
System.ServiceModel.Dispatcher.IDispatchMessageInspector的所有完整真实代码？对使用WebService ASMX的客户端有效？
OperationContext context = OperationContext.Current;

if (context != null && context.RequestContext != null)

{

Message msg = context.RequestContext.RequestMessage;

string reqXML = msg.ToString();

}