Owin Serve Dynamic Files

OwinDynamicFilesExtension.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Threading.Tasks;
using System.Web;

namespace Owin
{
    using AppFunc = Func<IDictionary<string, object>, Task>;

    public static class DynamicFileExtension
    {    
        /// <summary>
        /// ONLY use during development
        /// </summary>
        public static void UseDynamicFiles(this IAppBuilder app, string baseDirectory)
        {
            app.Use(new Func<AppFunc, AppFunc>(next => (async context =>
            {
                var method = (string) context["owin.RequestMethod"];
                var requestpath = (string) context["owin.RequestPath"];
                var scheme = (string) context["owin.RequestScheme"];
                var response = (Stream) context["owin.ResponseBody"];
                var responseHeader = (Dictionary<string, string[]>) context["owin.ResponseHeaders"];
               
                if (method == "GET" && scheme == "http")
                {
                    var fullpath = baseDirectory + requestpath;

                    if (File.Exists(fullpath))
                    {
                        using (var file = File.OpenRead(fullpath))
                        {
                            await file.CopyToAsync(response);
                        }

                        var mime = MimeMapping.GetMimeMapping(fullpath);

                        responseHeader.Add("Content-Type", new[] {mime});

                        return;
                    }
                }

                await next.Invoke(context);
            })));
        }
    }
}