Logging raw and compressed HTTP responses in ASP.NET & IIS7

Question

Along the lines of this question I want to create a HttpModule that will do some custom logging of requests and responses for us. Using the code in the most popular answer for that question I've got a HttpModule up and running which does indeed work:

class PortalTrafficModule : IHttpModule
{
    public void Dispose()
    {
        // Do Nothing
    }

    public void Init(HttpApplication context)
    {
        context.BeginRequest += new EventHandler(context_BeginRequest);
        context.EndRequest += new EventHandler(context_EndRequest);
    }

    private void context_BeginRequest(object sender, EventArgs e)
    {
        HttpContext context = ((HttpApplication)sender).Context;

        // Create and attach the OutputFilterStream to the Response and store it for later retrieval.
        OutputFilterStream filter = new OutputFilterStream(context.Response.Filter);
        context.Response.Filter = filter;
        context.Items.Add("OutputFilter", filter);

        // TODO: If required the request headers and content could be recorded here
    }

    private void context_EndRequest(object sender, EventArgs e)
    {
        HttpContext context = ((HttpApplication)sender).Context;
        OutputFilterStream filter = context.Items["OutputFilter"] as OutputFilterStream;

        if (filter != null)
        {
            // TODO: Log here - for now just debug.
            Debug.WriteLine("{0},{1},{2}",
                context.Response.Status,
                context.Request.Path,
                filter.ReadStream().Length);
        }
    }
}

(note that the OutputFilterStream class referred to in the code is in the referenced question).

However, the responses seem to be missing some HTTP headers that I see in Fiddler (like "Date") and more importantly, when I turn on compression the responses I'm logging aren't compressed whereas what I see in Fiddler is.

So my question - is it possible to log the compressed content or is this happening in a subsequent step my module can't hook in to?

For the record, I've also tried handling the PreSendRequestContent event and the response is still uncompressed.

Lossa

No, afraid not, and abandoned what I was doing shortly after! Good luck! – Lossa

Answer 1

Hi although I cannot answer your questions directly I have had cause to do similar things in the past and have found the following resource extremely helpful and enlightening. In the end I managed to acheive what I needed for raw soap headers by configuring the System.Diagnostics node within web config and create a trace log of traffic. I understand that your needs may be more granular than that however I believe this resource may still help.

http://msdn.microsoft.com/en-us/library/ms731859

Of particular interest may be the message log configuration and viewing message logs links from the one above.

Puddle