public void ConfigureAuth(IAppBuilder app){    app.UseCookieAuthentication(new CookieAuthenticationOptions    {        AuthenticationType = DefaultAuthenticationTypes.ApplicationCookie,        LoginPath = new PathString("/Account/Login"),        Provider = new CookieAuthenticationProvider()        {            OnApplyRedirect = ctx =>            {                if (!IsApiRequest(ctx.Request))                {                    ctx.Response.Redirect(ctx.RedirectUri);                }            }        }    });    app.UseExternalSignInCookie(DefaultAuthenticationTypes.ExternalCookie);}private static bool IsApiRequest(IOwinRequest request){    string apiPath = VirtualPathUtility.ToAbsolute("~/api/");    return request.Uri.LocalPath.StartsWith(apiPath);}