using System;
using System.Collections.Generic;
using System.IO.Compression;
using System.Linq;
using System.Web;

namespace Teknik.Modules
{
    public class CompressionModule : IHttpModule
    {
        public void Dispose()
        {
        }

        public void Init(HttpApplication context)
        {
            context.BeginRequest += delegate (object sender, EventArgs args)
            {
                HttpContext requestContext = ((HttpApplication)sender).Context;

                var encodingsAccepted = requestContext.Request.Headers["Accept-Encoding"];
                if (string.IsNullOrEmpty(encodingsAccepted)) return;

                encodingsAccepted = encodingsAccepted.ToLowerInvariant();
                var response = requestContext.Response;

                if (encodingsAccepted.Contains("gzip"))
                {
                    response.AppendHeader("Content-Encoding", "gzip");
                    response.Filter = new GZipStream(response.Filter, CompressionMode.Compress);
                }
            };
        }
    }
}