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SoapExtension Class

The base class for SOAP extensions for XML Web services created using ASP.NET.

Namespace: System.Web.Services.Protocols
Assembly: System.Web.Services (in system.web.services.dll)
public abstract class SoapExtension
public abstract class SoapExtension
public abstract class SoapExtension
Not applicable.

ASP.NET allows a SOAP-related infrastructure to be built by means of an extensibility mechanism. The ASP.NET SOAP extension architecture revolves around an extension that can inspect or modify a message at specific stages in message processing on either the client or the server.

ASP.NET SOAP extensions derive from the SoapExtension class. The GetInitializer and Initialize methods provide alternative mechanisms for initializing the SOAP extension to enhance performance. ProcessMessage is the heart of most SOAP extensions, as the method is called at each stage defined in SoapMessageStage, allowing the SOAP extension to perform the desired behavior of that specific SOAP extension. For SOAP extensions that need to modify the SOAP request or SOAP response, ChainStream provides an opportunity to receive the proposed data to be sent across the wire.

The following TraceExtension SOAP extension outputs the SOAP request and SOAP response to a specified file when applied to an XML Web service method. If the following SOAP extension is installed to run with an XML Web service, the ASPNET user account must have permission to write to the directory in which the log file is written.

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;
		}

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

	// Create a SoapExtensionAttribute for the SOAP Extension that can be
	// applied to an XML Web service method.
	[AttributeUsage(AttributeTargets.Method)]
	public class TraceExtensionAttribute : SoapExtensionAttribute 
	{

		private string filename = "c:\\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;
			}
		}
	}

import System.*;
import System.Web.Services.*;
import System.Web.Services.Protocols.*;
import System.IO.*;
import 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 extends SoapExtension
{
    private Stream oldStream;
    private Stream newStream;
    private String filename;

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

    // 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 Object GetInitializer(LogicalMethodInfo methodInfo, 
        SoapExtensionAttribute attribute)
    {
        return ((TraceExtensionAttribute)(attribute)).get_Filename();
    } //GetInitializer

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

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

    //  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 void ProcessMessage(SoapMessage message)
    {
        switch (message.get_Stage()) {
            case SoapMessageStage.BeforeSerialize :
                break;

            case SoapMessageStage.AfterSerialize :
                WriteOutput(message);
                break;

            case SoapMessageStage.BeforeDeserialize :
                WriteInput(message);
                break;

            case SoapMessageStage.AfterDeserialize :
                break;
       }
    } //ProcessMessage

    public void WriteOutput(SoapMessage message)
    {
        newStream.set_Position(0);

        FileStream fs = 
            new FileStream(filename, FileMode.Append, FileAccess.Write);
        StreamWriter w = new StreamWriter(fs);
        String soapString = (message instanceof SoapServerMessage) ? 
                            "SoapResponse" : "SoapRequest";

        w.WriteLine(("-----" + soapString + " at " + DateTime.get_Now()));
        w.Flush();
        Copy(newStream, fs);
        w.Close();
        newStream.set_Position(0);
        Copy(newStream, oldStream);
    } //WriteOutput

    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 instanceof SoapServerMessage) ? 
                            "SoapRequest" : "SoapResponse";

        w.WriteLine(("-----" + soapString + " at " + DateTime.get_Now()));
        w.Flush();
        newStream.set_Position(0);
        Copy(newStream, fs);
        w.Close();
        newStream.set_Position(0);
    } //WriteInput

    void Copy(Stream from, Stream to)
    {
        TextReader reader = new StreamReader(from);
        TextWriter writer = new StreamWriter(to);

        writer.WriteLine(reader.ReadToEnd());
        writer.Flush();
    } //Copy
} //TraceExtension


// Create a SoapExtensionAttribute for the SOAP Extension that can be
// applied to an XML Web service method.

/** @attribute AttributeUsage(AttributeTargets.Method)
 */
public class TraceExtensionAttribute extends SoapExtensionAttribute
{
    private String filename = "c:\\log.txt";
    private int priority;

    public Type get_ExtensionType()
    {
        return TraceExtension.class.ToType();
    } //get_ExtensionType

    public int get_Priority()
    {
        return priority;
    } //get_Priority

    public void set_Priority(int value)
    {
        priority = value;
    } //set_Priority

    public String get_Filename()
    {
        return filename;
    } //get_Filename

    public void set_Filename(String value)
    {
        filename = value;
    } //set_Filename
} //TraceExtensionAttribute

System.Object
  System.Web.Services.Protocols.SoapExtension
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0
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