Google Calendar v3 Authentication (WORKING!)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

using System.IO;
using System.Threading;

using Google.Apis.Calendar.v3;
using Google.Apis.Calendar.v3.Data;
using Google.Apis.Auth.OAuth2;
using Google.Apis.Auth.OAuth2.Flows;
using Google.Apis.Auth.OAuth2.Web;
using Google.Apis.Services;
using Google.Apis.Util.Store;

namespace GoogleCalendarV3
{
    public partial class GoogleCalendarV3 : System.Web.UI.Page
    {
        CalendarService service;
        private const string ApplicationName = "DFW Install Calendar App";

        // Application logic should manage users authentication. This sample works with only one user. You can change
        // it by retrieving data from the session.
        private const string UserId = "user-id";
        static string gFolder = System.Web.HttpContext.Current.Server.MapPath("/App_Data/MyGoogleStorage");

        protected void Page_Load(object sender, EventArgs e)
        {
            Response.Write(gFolder);
        }

        public static GoogleClientSecrets GetClientConfiguration()
        {
            using (var stream = new FileStream(gFolder + @"\client_secrets.json", FileMode.Open, FileAccess.Read))
            {
                return GoogleClientSecrets.Load(stream);
            }
        }

        protected void btnAuthenticate_Click(object sender, EventArgs e)
        {
            IAuthorizationCodeFlow flow =
               new GoogleAuthorizationCodeFlow(
                   new GoogleAuthorizationCodeFlow.Initializer
                   {
                       ClientSecrets = GetClientConfiguration().Secrets,
                       DataStore = new FileDataStore(gFolder),
                       Scopes = new[] { CalendarService.Scope.Calendar }
                   });

            var uri = Request.Url.ToString();
            var code = Request["code"];
            if (code != null)
            {
                var token = flow.ExchangeCodeForTokenAsync(UserId, code,
                    uri.Substring(0, uri.IndexOf("?")), CancellationToken.None).Result;

                // Extract the right state.
                var oauthState = AuthWebUtility.ExtracRedirectFromState(
                    flow.DataStore, UserId, Request["state"]).Result;
                Response.Redirect(oauthState);
            }
            else
            {
                var result = new AuthorizationCodeWebApp(flow, uri, uri).AuthorizeAsync(UserId,
                    CancellationToken.None).Result;
                if (result.RedirectUri != null)
                {
                    // Redirect the user to the authorization server.
                    Response.Redirect(result.RedirectUri);
                }
                else
                {
                    // The data store contains the user credential, so the user has been already authenticated.
                    service = new CalendarService(new BaseClientService.Initializer
                    {
                        ApplicationName = "Calendar API Sample",
                        HttpClientInitializer = result.Credential
                    });
                }
            }
        }
    }
}