title: How do I display raw SOAP messages from an asmx web service using SoapExtension
body: <p>I'm trying to make a simple test program to display the soap message sent between an aspx page and the asmx service it uses. I've tried doing the SoapExtension class and modifying my web.config, but nothing seems to work at all. This is what I have:</p>
  
  <p>Web config:</p>
  
  <pre><code>&lt;?xml version="1.0"?&gt;
  
  &lt;!--
    For more information on how to configure your ASP.NET application, please visit
    http://go.microsoft.com/fwlink/?LinkId=169433
    --&gt;
  
  &lt;configuration&gt;
  
    &lt;connectionStrings&gt;
      &lt;add name="ApplicationServices"
           connectionString="data source=.\SQLEXPRESS;Integrated Security=SSPI;AttachDBFilename=|DataDirectory|\aspnetdb.mdf;User Instance=true"
           providerName="System.Data.SqlClient" /&gt;
    &lt;/connectionStrings&gt;
  
    &lt;system.web&gt;
      &lt;compilation debug="true" targetFramework="4.0" /&gt;
  
      &lt;membership&gt;
        &lt;providers&gt;
          &lt;clear/&gt;
          &lt;add name="AspNetSqlMembershipProvider" type="System.Web.Security.SqlMembershipProvider" connectionStringName="ApplicationServices"
               enablePasswordRetrieval="false" enablePasswordReset="true" requiresQuestionAndAnswer="false" requiresUniqueEmail="false"
               maxInvalidPasswordAttempts="5" minRequiredPasswordLength="6" minRequiredNonalphanumericCharacters="0" passwordAttemptWindow="10"
               applicationName="/" /&gt;
        &lt;/providers&gt;
      &lt;/membership&gt;
  
      &lt;webServices&gt;
        &lt;soapExtensionTypes&gt;
          &lt;add type="TraceExtension.TraceExtension, TraceExtension"
             priority="1" group="High" /&gt;
        &lt;/soapExtensionTypes&gt;
      &lt;/webServices&gt;
  
      &lt;profile&gt;
        &lt;providers&gt;
          &lt;clear/&gt;
          &lt;add name="AspNetSqlProfileProvider" type="System.Web.Profile.SqlProfileProvider" connectionStringName="ApplicationServices" applicationName="/"/&gt;
        &lt;/providers&gt;
      &lt;/profile&gt;
  
      &lt;roleManager enabled="false"&gt;
        &lt;providers&gt;
          &lt;clear/&gt;
          &lt;add name="AspNetSqlRoleProvider" type="System.Web.Security.SqlRoleProvider" connectionStringName="ApplicationServices" applicationName="/" /&gt;
          &lt;add name="AspNetWindowsTokenRoleProvider" type="System.Web.Security.WindowsTokenRoleProvider" applicationName="/" /&gt;
        &lt;/providers&gt;
      &lt;/roleManager&gt;
  
    &lt;/system.web&gt;
  
  
    &lt;system.webServer&gt;
       &lt;modules runAllManagedModulesForAllRequests="true"/&gt;
    &lt;/system.webServer&gt;
    &lt;system.serviceModel&gt;
      &lt;behaviors&gt;
        &lt;serviceBehaviors&gt;
          &lt;behavior name=""&gt;
            &lt;serviceMetadata httpGetEnabled="true" /&gt;
            &lt;serviceDebug includeExceptionDetailInFaults="false" /&gt;
          &lt;/behavior&gt;
        &lt;/serviceBehaviors&gt;
      &lt;/behaviors&gt;
      &lt;serviceHostingEnvironment multipleSiteBindingsEnabled="true" /&gt;
      &lt;bindings /&gt;
      &lt;client /&gt;
    &lt;/system.serviceModel&gt;
  &lt;/configuration&gt;
  </code></pre>
  
  <p>Simple calling page that calls the HelloWorld function from the service and puts the returned string into a label:</p>
  
  <pre><code>using System;
  using System.Collections.Generic;
  using System.Linq;
  using System.Web;
  using System.Web.UI;
  using System.Web.UI.WebControls;
  using System.Web.Services;
  using System.Web.Services.Protocols;
  using System.IO;
  
  namespace CS606_SOAP
  {
      public partial class _Default : System.Web.UI.Page
      {
          protected void Page_Load(object sender, EventArgs e)
          {
  
          }
  
          protected void Button1_Click(object sender, EventArgs e)
          {
              WebService1 svc = new WebService1();
              Label1.Text = svc.HelloWorld();
          }
      }
  }
  </code></pre>
  
  <p>Here is the asmx:</p>
  
  <pre><code>using System;
  using System.Collections.Generic;
  using System.Linq;
  using System.Web;
  using System.Web.Services;
  using System.Web.Services.Protocols;
  
  namespace CS606_SOAP
  {
      /// &lt;summary&gt;
      /// Summary description for WebService1
      /// &lt;/summary&gt;
      [WebService(Namespace = "http://tempuri.org/")]
      [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
      [System.ComponentModel.ToolboxItem(false)]
      // To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line. 
      // [System.Web.Script.Services.ScriptService]
      public class WebService1 : System.Web.Services.WebService
      {
          [TraceExtension.TraceExtension]
          [WebMethod]
          public string HelloWorld()
          {
              return "Hello World";
          }
      }
  
  }
  </code></pre>
  
  <p>I also have a refernce to a .dll file of the classes here:</p>
  
  <pre><code>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.
  namespace TraceExtension
  {
      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 = "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;
              }
          }
      }
  }
  </code></pre>
  
  <p>It runs fine but nothing actually gets written to the log.txt file. Anyone know what's wrong here? Using .Net 4.0 btw.</p>