GZip and Deflate IHttpModule

gistfile1.cs

using System;
using System.Collections.Generic;
using System.Text;
using System.Web;
using System.IO;
using System.IO.Compression;
namespace Compression
{
    public class PageCompressionModule : IHttpModule
    {
        public void Dispose()
        {
        }

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

        void context_BeginRequest(object sender, EventArgs e)
        {
            //
            // Get the application object to gain access to the request's details
            //
            HttpApplication app = (HttpApplication)sender;

            //
            // Accepted encodings
            //
            string encodings = app.Request.Headers.Get("Accept-Encoding");

            //
            // No encodings; stop the HTTP Module processing
            //
            if (encodings == null)
                return;
            //
            // Current response stream
            //
            Stream baseStream = app.Response.Filter;

            //
            // Check the browser accepts gzip or deflate (gzip takes preference)
            //
            encodings = encodings.ToLower();
            if (encodings.Contains("gzip"))
            {
                app.Response.Filter = new GZipStream(baseStream, CompressionMode.Compress);
                app.Response.AppendHeader("Content-Encoding", "gzip");
                app.Context.Trace.Warn("GZIP compression on");
            }
            else if (encodings.Contains("deflate"))
            {
                app.Response.Filter = new DeflateStream(baseStream, CompressionMode.Compress);
                app.Response.AppendHeader("Content-Encoding", "deflate");
                app.Context.Trace.Warn("Deflate compression on");
            }
        }
    }
}