BoxKite.Twitter.Authentication.TwitterAuthenticator.XAuthentication C# (CSharp) Метод

        public static async Task<TwitterCredentials> XAuthentication(this IUserSession session, string xauthusername,
            string xauthpassword)
        {
            if (string.IsNullOrWhiteSpace(session.clientID))
                throw new ArgumentException("ClientID must be specified", session.clientID);

            if (string.IsNullOrWhiteSpace(session.clientSecret))
                throw new ArgumentException("ClientSecret must be specified", session.clientSecret);

            var sinceEpoch = session.GenerateTimestamp();
            var nonce = session.GenerateNoonce();

            var sigBaseStringParams =
                string.Format(
                    "oauth_consumer_key={0}&oauth_nonce={1}&oauth_signature_method=HMAC-SHA1&oauth_timestamp={2}&oauth_version=1.0",
                    session.clientID,
                    nonce,
                    sinceEpoch);

            var sigBaseString = string.Format("POST&{0}&{1}", TwitterApi.XAuthorizeTokenUrl().UrlEncode(),
                sigBaseStringParams.UrlEncode());
            var signature = session.GenerateSignature(session.clientSecret, sigBaseString, null);
            var dataToPost = string.Format(
                "OAuth oauth_consumer_key=\"{2}\",oauth_nonce=\"{0}\",oauth_signature=\"{3}\",oauth_signature_method=\"HMAC-SHA1\",oauth_timestamp=\"{1}\",oauth_version=\"1.0\"",
                nonce,
                sinceEpoch,
                session.clientID,
                signature.UrlEncode());

            var contentToPost = string.Format(
                "x_auth_username={0}&x_auth_password={1}&x_auth_mode=client_auth",
                xauthusername.UrlEncode(),
                xauthpassword.UrlEncode());

            var authresponse = await PostData(TwitterApi.XAuthorizeTokenUrl(), dataToPost, contentToPost);

            var _accessToken = "";
            var _accessTokenSecret = "";
            var _userId = "";
            var _screenName = "";

            foreach (var splits in authresponse.Split('&').Select(t => t.Split('=')))
            {
                switch (splits[0])
                {
                    case "oauth_token": //these tokens are request tokens, first step before getting access tokens
                        _accessToken = splits[1];
                        break;
                    case "oauth_token_secret":
                        _accessTokenSecret = splits[1];
                        break;
                    case "user_id":
                        _userId = splits[1];
                        break;
                    case "screen_name":
                        _screenName = splits[1];
                        break;
                }
            }

            if (_accessToken != null && _accessTokenSecret != null && _userId != null && _screenName != null)
            {
                return new TwitterCredentials()
                {
                    ConsumerKey = session.clientID,
                    ConsumerSecret = session.clientSecret,
                    ScreenName = _screenName,
                    Token = _accessToken,
                    TokenSecret = _accessTokenSecret,
                    UserID = Int64.Parse(_userId),
                    Valid = true
                };
            }
            return TwitterCredentials.Null;
        }