A workable IIS module to log session to file

%systemroot%\Microsoft.NET\Framework64\v2.0.50727\csc.exe /target:library /out:IIS_MOD_REQDATA.dll /debug /d:TRACE /R:System.Web.dll IIS_MOD_REQDATA.cs
copy IIS_MOD_REQDATA.dll C:\TestMembershipProvider\bin\

using System;
using System.Collections.Generic;
using System.Text;
using System.Web;
using System.Diagnostics;
using System.Web.Security;
using System.Web.SessionState;

namespace IIS_MOD_REQDATA
{
    public class IIS_MOD_REQDATA : IHttpModule
    {

        TraceSource tsStatus;

        public void Init(HttpApplication application)
        {
            application.EndRequest += (new EventHandler(this.Application_EndRequest));

            // TRACING
            tsStatus = new TraceSource("tsStatus");
      application.PostAcquireRequestState += new EventHandler(Application_PostAcquireRequestState);
      application.PostMapRequestHandler += new EventHandler(Application_PostMapRequestHandler);
        }

        private void Application_EndRequest(Object source, EventArgs e)
        {
            HttpApplication application = (HttpApplication)source;
            HttpContext context = application.Context;

            tsStatus.TraceEvent(TraceEventType.Start, 0, "[REQDATA MODULE] START EndRequest");

            // start writing out the request data
            context.Response.Write("<hr>");
            context.Response.Write("<b><font size=2 color=green>REQUEST HEADERS</font></b><br>");
            context.Response.Write("<font size=2>");
            context.Response.Write("METHOD : " + context.Request.HttpMethod + "<br>");
            context.Response.Write("URL : " + context.Request.Url + "<br>");
            context.Response.Write("QUERYSTRING : " + context.Request.QueryString + "<br>");
            context.Response.Write("</font><br>");

            tsStatus.TraceEvent(TraceEventType.Verbose, 0, "[REQDATA MODULE] done with Req Data, moving onto Response");

            // now response data

            context.Response.Write("<b><font size=2 color=blue>RESPONSE HEADERS</font></b><br>");
            context.Response.Write("<font size=2>");
            context.Response.Write("STATUS CODE : " + context.Response.StatusCode.ToString() + "." + context.Response.SubStatusCode.ToString() + "<br>");
            context.Response.Write("CONTENT TYPE : " + context.Response.ContentType.ToString() + "<br>");
            context.Response.Write("EXPIRES : " + context.Response.Expires.ToString() + "<br>");
            context.Response.Write("</font><br>");

            if (context.Response.StatusCode > 399)
            {
                tsStatus.TraceEvent(TraceEventType.Warning, 0, "[REQDATA MODULE] error status code detected");
            }

            tsStatus.TraceEvent(TraceEventType.Verbose, 0, "[REQDATA MODULE] done with Response Data");

            // set cache policy on response so it's not cached.
            context.Response.DisableKernelCache();
            tsStatus.TraceEvent(TraceEventType.Verbose, 0, "[REQDATA MODULE] cache setting is (" + context.Response.Cache.ToString() + ")");

            tsStatus.TraceEvent(TraceEventType.Stop, 0, "[REQDATA MODULE] STOP - EndRequest");
        }

void Application_PostMapRequestHandler(object source, EventArgs e)
   {
      HttpApplication app = (HttpApplication)source;

      if (app.Context.Handler is IReadOnlySessionState || app.Context.Handler is IRequiresSessionState) {
         // no need to replace the current handler
         return;
      }
      // swap the current handler
      app.Context.Handler = new MyHttpHandler(app.Context.Handler);
   }

   void Application_PostAcquireRequestState(object source, EventArgs e)
   {
      HttpApplication app = (HttpApplication)source;

      MyHttpHandler resourceHttpHandler = HttpContext.Current.Handler as MyHttpHandler;

      if (resourceHttpHandler != null) {
         // set the original handler back
         HttpContext.Current.Handler = resourceHttpHandler.OriginalHandler;
      }
      // -> at this point session state should be available

      Debug.Assert(app.Session != null, "it did not work :(");
using (System.IO.StreamWriter file=new System.IO.StreamWriter(@"C:\PeterLog.txt", true))
             {
		string username=null;
		try{
			username=app.Session["Key1"].ToString();
		}catch{
                	//file.WriteLine(ex.Message);
		}
                file.WriteLine(app.Context.Request.Url+ " : "+username);
             }
   }
  public class MyHttpHandler : IHttpHandler, IRequiresSessionState
   {
      internal readonly IHttpHandler OriginalHandler;

      public MyHttpHandler(IHttpHandler originalHandler)
      {
         OriginalHandler = originalHandler;
      }

      public void ProcessRequest(HttpContext context)
      {
         // do not worry, ProcessRequest() will not be called, but let's be safe
         throw new InvalidOperationException("MyHttpHandler cannot process requests.");
      }

      public bool IsReusable
      {
         // IsReusable must be set to false since class has a member!
         get { return false; }
      }
   }

        public void Dispose()
        {
        }
    }
}