A gzip, deflate compression middleware for vNext, ASP.NET Core

CompressionMiddleware.cs

    public class CompressionMiddleware
    {
        private readonly RequestDelegate _next;

        public CompressionMiddleware(RequestDelegate next)
        {
            _next = next;
        }

        public async Task Invoke(HttpContext context)
        {
            if (IsGZipSupported(context))
            {
                string acceptEncoding = context.Request.Headers["Accept-Encoding"];

                var buffer = new MemoryStream();
                var stream = context.Response.Body;
                context.Response.Body = buffer;
                await _next(context);

                if (acceptEncoding.Contains("gzip"))
                {
                    var gstream = new GZipStream(stream, CompressionLevel.Optimal);
                    context.Response.Headers.Add("Content-Encoding", new[] {"gzip"});
                    buffer.Seek(0, SeekOrigin.Begin);
                    await buffer.CopyToAsync(gstream);
                    gstream.Dispose();
                }
                else
                {
                    var gstream = new DeflateStream(stream, CompressionLevel.Optimal);
                    context.Response.Headers.Add("Content-Encoding", new[] { "deflate" });
                    buffer.Seek(0, SeekOrigin.Begin);
                    await buffer.CopyToAsync(gstream);
                    gstream.Dispose();
                }
            }
            else
            {
                await _next(context);
            }
        }

        public bool IsGZipSupported(HttpContext context)
        {
            string acceptEncoding = context.Request.Headers["Accept-Encoding"];
            return !string.IsNullOrEmpty(acceptEncoding) &&
                   (acceptEncoding.Contains("gzip") || acceptEncoding.Contains("deflate"));
        }
    }

add app.UseMiddleware<CompressionMiddleware>(); to your request pipeline within the Configure method in your Startup.cs

this (along with other copy pasta implementations) only works on the first request. All other requests have content length of 0. Any idea?

@matthewdaniel if you send me a sample solution or unit test I'll take a look