public async Task Invoke(IDictionary<string, object> env)
        {
            object value;
            if (env.TryGetValue("server.User", out value))
            {
                var windowsPrincipal = value as WindowsPrincipal;
                if (windowsPrincipal != null && windowsPrincipal.Identity.IsAuthenticated)
                {
                    await _next(env);

                    var request = new OwinRequest(env);
                    var response = new OwinResponse(env);

                    if (response.StatusCode == 401)
                    {
                        // We're going no add the identifier claim
                        var nameClaim = windowsPrincipal.FindFirst(ClaimTypes.Name);

                        // This is the domain name
                        string name = nameClaim.Value;

                        // If the name is something like DOMAIN\username then
                        // grab the name part
                        var parts = name.Split(new[] { '\\' }, 2);

                        string shortName = parts.Length == 1 ? parts[0] : parts[parts.Length - 1];

                        // REVIEW: Do we want to preserve the other claims?

                        // Normalize the claims here
                        var claims = new List<Claim>();
                        claims.Add(new Claim(ClaimTypes.NameIdentifier, name));
                        claims.Add(new Claim(ClaimTypes.Name, shortName));
                        claims.Add(new Claim(ClaimTypes.AuthenticationMethod, "Windows"));
                        var identity = new ClaimsIdentity(claims, Constants.JabbRAuthType);
                        var claimsPrincipal = new ClaimsPrincipal(identity);

                        response.SignIn(claimsPrincipal);

                        response.StatusCode = 302;
                        response.SetHeader("Location", request.PathBase + request.Path);
                    }

                    return;
                }
            }

            await _next(env);
        }