public static double getAuthToken(string authCode)
    {
        AuthenticationKeys   auth       = new AuthenticationKeys();
        MapAccessCredentials outputData = new MapAccessCredentials();

        try
        {
            HttpContext.Current.Session["userAuthData"] = null;
            string uri        = "https://login.uber.com/oauth/v2/token?client_secret=" + auth.uberClientSecret + "&client_id=" + auth.uberClientId + "&grant_type=authorization_code&redirect_uri=http://localhost:63685/KzUber/booking.html&code=" + authCode;
            var    webRequest = (HttpWebRequest)WebRequest.Create(uri);
            webRequest.Method = "POST";
            var webResponse = (HttpWebResponse)webRequest.GetResponse();
            if ((webResponse.StatusCode == HttpStatusCode.OK) && (webResponse.ContentLength > 0))
            {
                var    reader = new StreamReader(webResponse.GetResponseStream());
                string s      = reader.ReadToEnd();
                outputData = JsonConvert.DeserializeObject <MapAccessCredentials>(s);
                AccessCredentials accessData = new AccessCredentials(outputData.last_authenticated, outputData.access_token, outputData.expires_in, outputData.token_type, outputData.scope, outputData.refresh_token);
                HttpContext.Current.Session["userAuthData"] = accessData;
                return(accessData.getExpiryTime());
            }
            else
            {
                Console.WriteLine("Error");
                return(-1);
            }
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex.Message);
            return(0);
        }
    }