gzipstream

gzipstream.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.IO.Compression;
using System.Threading.Tasks;
using Microsoft.Owin;

namespace ZipMiddleware
{
    using AppFunc = Func<IDictionary<string, object>, Task>;
    public class GzipMiddleware
    {
        private readonly AppFunc _next;

        public GzipMiddleware(AppFunc next)
        {
            this._next = next;
        }

        public async Task Invoke(IDictionary<string, object> env)
        {
            var ctx = new OwinContext(env);
            var encodingHeaders = ctx.Request.Headers.GetCommaSeparatedValues("Accept-Encoding");
            var acceptGzip = encodingHeaders != null && encodingHeaders.Contains("gzip");

            if (acceptGzip)
            {
                ctx.Response.Body = new BufferedStream(new GZipStream(ctx.Response.Body,CompressionLevel.Fastest));
                ctx.Response.OnSendingHeaders(state =>
                {
                    var resp = (OwinResponse)state;
                    resp.Headers.Set("Content-Encoding", "gzip");
                    resp.Headers.Add("Transfer-Encoding",new[] {"chunked"});
                }, ctx.Response);
            }
            await _next(env);
            ctx.Response.Body.Close();
        }
    }
}