yavsc/web/Controllers/GoogleController.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Threading;
using System.Web.Mvc;
using System.Configuration;
using System.Threading.Tasks;
using System.Text;
using Mono.Security.Protocol.Tls;
using System.Net;
using System.IO;
using Yavsc.Model;
using Newtonsoft.Json;

namespace Yavsc.Controllers
{
	public class TokenResult {
		public string access_token { get; set; }
		public string id_token { get; set; }
		public int expires_in { get; set; }
		public string token_type { get; set ; }
		public string refresh_token { get; set; }
	}

	public class GoogleController : Controller
	{

		private string API_KEY="AIzaSyBV_LQHb22nGgjNvFzZwnQHjao3Q7IewRw";

		private string CLIENT_ID="325408689282-6bekh7p3guj4k0f3301a6frf025cnrk1.apps.googleusercontent.com";

		private string CLIENT_SECRET="MaxYcvJJCs2gDGvaELZbzwfL";

		string [] SCOPES = { 
			"profile",
			"email"
		} ; 

		string tokenUri = "https://accounts.google.com/o/oauth2/token"; 
		string authUri = "https://accounts.google.com/o/oauth2/auth";

		public void Login()
		{
			Random rand = new Random ();
			string state = "security_token"+rand.Next (100000).ToString()+rand.Next (100000).ToString();
			Session ["state"] = state;

			string redirectUri = Request.Url.Scheme + "://" + Request.Url.Authority + "/Google/Auth";

			string prms = String.Format("response_type=code&" +
				"client_id={0}&" +
				"redirect_uri={1}&" +
				"scope={2}&" +
				"state={3}&" +
				"access_type=offline&" +
				"include_granted_scopes=false",
				CLIENT_ID,
				redirectUri,
				string.Join("%20",SCOPES),
				state
			);

			WebRequest wr = WebRequest.Create(authUri+"?"+prms);

			wr.Method = "GET";
			// Get the response.
			try {
				WebResponse response = wr.GetResponse();
				string resQuery = response.ResponseUri.Query;
				string cont = HttpUtility.ParseQueryString(resQuery)["continue"];
				Response.Redirect (cont);
			}
			catch (WebException we) {
				Response.Redirect(we.Response.ResponseUri.AbsoluteUri);
			}

		}
		public void Auth() {
			string redirectUri = Request.Url.Scheme + "://" + Request.Url.Authority + "/Google/Auth";
			string code = Request.Params ["code"];
			string error = Request.Params ["error"];
			if (error != null) {
				ViewData ["Message"] = 
					string.Format(LocalizedText.Google_error,
						LocalizedText.ResourceManager.GetString(error));
				return;
			}
			string state = Request.Params ["state"];
			if (state!=null && string.Compare((string)Session ["state"],state)!=0) {
				ViewData ["Message"] = 
					LocalizedText.ResourceManager.GetString("invalid request state");
				return;
			}

			string postdata = 
				string.Format(
					"redirect_uri={0}&client_id={1}&client_secret={2}&code={3}&grant_type=authorization_code",
					HttpUtility.UrlEncode(redirectUri),
					HttpUtility.UrlEncode(CLIENT_ID),
					HttpUtility.UrlEncode(CLIENT_SECRET),
					HttpUtility.UrlEncode(code));

			Byte[] bytes = System.Text.Encoding.UTF8.GetBytes (postdata);
			HttpWebRequest webreq = WebRequest.CreateHttp (tokenUri);
			webreq.Method = "POST";
			webreq.Accept = "application/json";
			webreq.ContentType = "application/x-www-form-urlencoded";
			webreq.ContentLength = bytes.Length;
			using (Stream dataStream = webreq.GetRequestStream ()) {
				dataStream.Write (bytes, 0, bytes.Length);
			};

			using (WebResponse response = webreq.GetResponse ()) {

				using (Stream responseStream = response.GetResponseStream ()) {
					using (StreamReader readStream = new StreamReader (responseStream, Encoding.ASCII)) {
						string responseStr = readStream.ReadToEnd ();
						TokenResult res = JsonConvert.DeserializeObject<TokenResult>(responseStr);

					}
				}
			}
		}

	}
}