.NET SoapExtension 无法修改服务器上的肥皂请求

Question

我正在尝试在 .NET 中实现一个 SoapExtension，它将压缩所有的肥皂流量（请求和响应）。我可以控制客户端和服务器。我已经开始复制这个：http://www.mastercsharp.com/article.aspx?ArticleID=86&&TopicID=7 并稍微修改它，我有一个问题。

当从客户端发送请求正文时，我能够修改（压缩）请求正文，它到达服务器，反向操作（解压缩）也很好，但我似乎无法让框架反映我对流对象所做的更改！在服务器上，我为 newStream 对象设置了正确的数据，但是当调用 WebMethod 时，参数仍然被压缩（因此无效）。知道为什么吗？

为了让包括我自己在内的每个人都更容易，我将 SoapExtension 简化为：

using System;
using System.Web.Services;
using System.Web.Services.Protocols;
using System.IO;
using System.Net;

// Define a SOAP Extension that traces the SOAP request and SOAP
// response for the XML Web service method the SOAP extension is
// applied to.

public class TraceExtension : SoapExtension {
Stream oldStream;
Stream newStream;
string filename;

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

// When the SOAP extension is accessed for the first time, the XML Web
// service method it is applied to is accessed to store the file
// name passed in, using the corresponding SoapExtensionAttribute.  
public override object GetInitializer(LogicalMethodInfo methodInfo, SoapExtensionAttribute attribute)
{
    return ((TraceExtensionAttribute)attribute).Filename;
}

// The SOAP extension was configured to run using a configuration file
// instead of an attribute applied to a specific XML Web service
// method.
public override object GetInitializer(Type WebServiceType)
{
    // Return a file name to log the trace information to, based on the
    // type.
    return "C:\\" + WebServiceType.FullName + ".log";
}

// Receive the file name stored by GetInitializer and store it in a
// member variable for this specific instance.
public override void Initialize(object initializer)
{
    filename = (string)initializer;
}

//  If the SoapMessageStage is such that the SoapRequest or
//  SoapResponse is still in the SOAP format to be sent or received,
//  save it out to a file.
public override void ProcessMessage(SoapMessage message)
{
    switch (message.Stage)
    {
        case SoapMessageStage.BeforeSerialize:
            break;
        case SoapMessageStage.AfterSerialize:
            WriteOutput(message);
            break;
        case SoapMessageStage.BeforeDeserialize:
            WriteInput(message);
            break;
        case SoapMessageStage.AfterDeserialize:
            break;
    }
}

public void WriteOutput(SoapMessage message)
{
    newStream.Position = 0;
    FileStream fs = new FileStream(filename, FileMode.Append,
        FileAccess.Write);
    StreamWriter w = new StreamWriter(fs);

    string soapString = (message is SoapServerMessage) ? "SoapResponse" : "SoapRequest";
    w.WriteLine("-----" + soapString + " at " + DateTime.Now);
    w.Flush();
    Copy(newStream, fs);
    w.Close();
    newStream.Position = 0;
    Copy(newStream, oldStream);
}

//public void WriteInput(SoapMessage message)
//{
//    Copy(oldStream, newStream);
//    FileStream fs = new FileStream(filename, FileMode.Append,
//        FileAccess.Write);
//    StreamWriter w = new StreamWriter(fs);

//    string soapString = (message is SoapServerMessage) ?
//        "SoapRequest" : "SoapResponse";
//    w.WriteLine("-----" + soapString +
//        " at " + DateTime.Now);
//    w.Flush();
//    newStream.Position = 0;
//    Copy(newStream, fs);
//    w.Close();
//    newStream.Position = 0;
//}


public void WriteInput(SoapMessage message)
{
    oldStream.Position = 0;
    StreamReader reader = new StreamReader(oldStream);
    StreamWriter writer = new StreamWriter(newStream);
    string data = reader.ReadToEnd();
    data = data.Replace("false", "true");
    writer.Write(data);
    writer.Flush();
}

void Copy(Stream from, Stream to)
{
    TextReader reader = new StreamReader(from);
    TextWriter writer = new StreamWriter(to);
    writer.WriteLine(reader.ReadToEnd());
    writer.Flush();
}

}

它仍然无法正常工作。当服务器（WriteInput 方法）收到soap 请求时，所有“false”值都更改为“true”并将数据保存到newStream 对象，但在webmethod 调用中仍会显示“false”值！

我的电话如下所示： 客户：

 [SoapDocumentMethodAttribute("http://Company.com/Product/admintool/webservices/SaveNativeRequest", RequestNamespace = "http://Company.com/Product/admintool/webservices/", ResponseNamespace = "http://Company.com/Product/admintool/webservices/", Use = SoapBindingUse.Literal, ParameterStyle = SoapParameterStyle.Wrapped)]
        [SoapHeaderAttribute("Ticket")]
        [TraceExtension(Priority = 0)]
        public void SaveNativeRequest(XmlNode nativeRequest, int? batchId)
        {
            this.Invoke("SaveNativeRequest", new object[] { nativeRequest, batchId });
        }

服务器：

 [WebMethod]
    [TraceExtension(Priority = 0)]
    [SoapHeader("Ticket", Direction = SoapHeaderDirection.In)]
    public void SaveNativeRequest(XmlNode nativeRequest, int? batchId)
    {...}

为了完整起见，这是属性类

// Create a SoapExtensionAttribute for the SOAP Extension that can be
// applied to an XML Web service method.
using System;
using System.Web.Services.Protocols;
[AttributeUsage(AttributeTargets.Method)]
public class TraceExtensionAttribute : SoapExtensionAttribute
{
    private string filename = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments) + @"\log.txt";
    private int priority;

    public override Type ExtensionType
    {
        get { return typeof(TraceExtension); }
    }

    public override int Priority
    {
        get { return priority; }
        set { priority = value; }
    }

    public string Filename
    {
        get
        {
            return filename;
        }
        set
        {
            filename = value;
        }
    }
}

我读过这篇文章：h**p://hyperthink.net/blog/inside-of-chainstream/，我很确定我正确地使用了 chainstream 方法。我知道还有其他方法可以做到这一点，但这看起来确实是一个干净的选择。我已经阅读了有关该主题的各种文章，这篇 http://msdn.microsoft.com/en-us/magazine/cc188761.aspx 文章启发了我一个解决方法，我可以使用

(System.Web.HttpContext.Current.Items["RequestSoapContext"] as Microsoft.Web.Services3.SoapContext).Envelope.Body

在 ProcessMessage 方法中直接操作皂体（这很好用，但是很丑）

我是否忽略了一些明显的东西？应用程序的其他部分是否会干扰服务器上的流链接？如果有人对此有任何见解，我将非常高兴。

Answer 1

我认为您需要在 WriteInput 方法中重置 newStream 的位置。

所以请在 WriteInput 方法的末尾添加以下行：

newStream.Position = 0;

应该可以解决你的问题。