OWIN Middleware for X-FORWARDED- Headers

Startup.cs

using Microsoft.Owin;
using Owin;
using System.Threading.Tasks;

[assembly: OwinStartup(typeof(OWINSample.Startup))]

namespace OWINSample
{
    public class Startup
    {
        public void Configuration(IAppBuilder app)
        {
            // Ensure this is the top most middleware
            app.Use<XForwardedMiddleware>();
        }
    }

    public class XForwardedMiddleware : OwinMiddleware
    {
        public XForwardedMiddleware(OwinMiddleware next) : base(next)
        {
        }

        public override Task Invoke(IOwinContext context)
        {
            var request = context.Request;
            var forwardedFor = request.Headers["X-Forwarded-For"];
            var forwardedProto = request.Headers["X-Forwarded-Proto"];
            var forwardedHost = request.Headers["X-Forwarded-Host"];

            if (!string.IsNullOrWhiteSpace(forwardedFor))
            {
                request.RemoteIpAddress = forwardedFor;
            }

            if (!string.IsNullOrWhiteSpace(forwardedProto))
            {
                request.Scheme = forwardedProto;
            }

            if (!string.IsNullOrWhiteSpace(forwardedHost))
            {
                request.Host = new HostString(forwardedHost);
            }

            return Next.Invoke(context);
        }
    }
}