code to get the oauth token from twitter api

AuthenticationSnippet.cs

        /// <summary>
        /// Gets bearer token for application-only authentication from Twitter API 1.1, obtaining key and secret from web.config/app.config.
        /// * NOTE: This token should be cached by the application -- for up to 15 mins.
        /// * Dependant on web.config appSettings params twitterConsumerKey and twitterConsumerSecret.
        /// * Twitter API client oAuth settings: https://dev.twitter.com/app
        /// * Application-only authentication: https://dev.twitter.com/docs/auth/application-only-auth
        /// * API endpoint oauth2/token: https://dev.twitter.com/docs/api/1.1/post/oauth2/token
        /// </summary>
        /// <returns>oAuth bearer token for Twitter API authentication.</returns>
        public async Task<string> GetBearerToken()
        {
            JToken token = JObject.Parse(
                await GetBearerTokenJson(
                   options.ConsumerKey,options.ConsumerSecret));

            return token.SelectToken("access_token").Value<string>();
        }

        /// <summary>
        /// Gets bearer token for application-only authentication from Twitter API 1.1.
        /// * NOTE: This token should be cached by the application -- for up to 15 mins.
        /// * Twitter API client oAuth settings: https://dev.twitter.com/app
        /// * Application-only authentication: https://dev.twitter.com/docs/auth/application-only-auth
        /// * API endpoint oauth2/token: https://dev.twitter.com/docs/api/1.1/post/oauth2/token
        /// </summary>
        /// <param name="consumerKey">Token obtained from authentication.</param>
        /// <param name="consumerSecret">Token obtained from authentication.</param>
        /// <returns>oAuth bearer token for Twitter API authentication.</returns>
        public async Task<string> GetBearerToken(string consumerKey, string consumerSecret)
        {
            JToken token = JObject.Parse(
                await GetBearerTokenJson(consumerKey, consumerSecret));

            return token.SelectToken("access_token").Value<string>();
        }

        private async static Task<string> GetBearerTokenJson(string consumerKey, string consumerSecret)
        {
            var webrequest = CreateRequest("/oauth2/token",HttpMethod.Get);

            webrequest.Headers.Add("Authorization", "Basic " + GetBasicAuthToken(consumerKey, consumerSecret));

            WriteRequest(webrequest, "grant_type=client_credentials");

            return await ReadResponse(webrequest);
        }