Upwork(formerly Odesk) API Call using C#

gistfile1.txt

 public static PublicInfoResponse LoadResponse()
  {
      PublicInfoResponse publicInfoResponse = (PublicInfoResponse)HttpRuntime.Cache["Odesk:PublicInfoResponse"];
      if (publicInfoResponse == null)
      {
          Models.OAuthParams parameters;
          string method = "GET";

          parameters = new Models.OAuthParams();
          parameters.Token = ConfigurationManager.AppSettings["apiKeys:UpworkoAuthToken"];
          parameters.TokenSecret = ConfigurationManager.AppSettings["apiKeys:UpworkoAuthValue"];
          parameters.ConsumerKey = ConfigurationManager.AppSettings["apiKeys:UpworkApiKey"];
          parameters.ConsumerSecret = ConfigurationManager.AppSettings["apiKeys:UpworkApiSecret"];
          var oDeskProfileKey = ConfigurationManager.AppSettings["apiKeys:UpworkProfileKey"];
          string resource_url = string.Format("https://www.odesk.com/api/profiles/v1/providers/~{0}.json", oDeskProfileKey);

          OAuthManager.GenerateOAuthParameters(parameters, resource_url, method);

          ServicePointManager.Expect100Continue = false;

          HttpWebRequest request = (HttpWebRequest)WebRequest.Create(resource_url);
          request.Headers.Add("Authorization", parameters.Header);
          request.Method = method;
          request.ContentType = "application/x-www-form-urlencoded";

          WebResponse response = request.GetResponse();
          var responseStream = response.GetResponseStream();
          var streamReader = new StreamReader(responseStream);
          var body = streamReader.ReadToEnd();

          JavaScriptSerializer ser = new JavaScriptSerializer();
          publicInfoResponse = ser.Deserialize<PublicInfoResponse>(body);
          HttpRuntime.Cache.Add("Odesk:PublicInfoResponse", publicInfoResponse, null, Cache.NoAbsoluteExpiration, new TimeSpan(1, 0, 0), CacheItemPriority.Normal, null);
      }
      return publicInfoResponse;
  }
        
  public static void GenerateOAuthParameters(Models.OAuthParams parameters, string resource_url, string method)
  {
      parameters.Version = "1.0";
      parameters.SignatureMethod = "HMAC-SHA1";
      parameters.Nonce = Convert.ToBase64String(
                                        new ASCIIEncoding().GetBytes(
                                             DateTime.Now.Ticks.ToString()));
      var timeSpan = DateTime.UtcNow
                                        - new DateTime(1970, 1, 1, 0, 0, 0, 0,
                                             DateTimeKind.Utc);
      parameters.Timestamp = Convert.ToInt64(timeSpan.TotalSeconds).ToString();

      //generate an encrypted oAuth signature which Twitter will use to validate the request. To do this, all of the request data is concatenated into a particular format as follows.
      var baseFormat = "oauth_consumer_key={0}&oauth_nonce={1}&oauth_signature_method={2}" +
          "&oauth_timestamp={3}&oauth_token={4}&oauth_version={5}";

      var baseString = string.Format(baseFormat,
                                  parameters.ConsumerKey,
                                  parameters.Nonce,
                                  parameters.SignatureMethod,
                                  parameters.Timestamp,
                                  parameters.Token,
                                  parameters.Version
                                  );

      baseString = string.Concat(method, "&", Uri.EscapeDataString(resource_url),
                   "&", Uri.EscapeDataString(baseString));

      //encrypt the data using a composite of the secret keys and the HMAC-SHA1 algorithm.
      var compositeKey = string.Concat(Uri.EscapeDataString(parameters.ConsumerSecret),
                  "&", Uri.EscapeDataString(parameters.TokenSecret));

      using (HMACSHA1 hasher = new HMACSHA1(ASCIIEncoding.ASCII.GetBytes(compositeKey)))
      {
          parameters.Signature = Convert.ToBase64String(
              hasher.ComputeHash(ASCIIEncoding.ASCII.GetBytes(baseString)));
      }

      //generate the Authentication header. This requires concatenating the public keys and the token generated above into the following format.
      var headerFormat = "OAuth oauth_nonce=\"{0}\", oauth_signature_method=\"{1}\", " +
            "oauth_timestamp=\"{2}\", oauth_consumer_key=\"{3}\", " +
            "oauth_token=\"{4}\", oauth_signature=\"{5}\", " +
            "oauth_version=\"{6}\"";

      parameters.Header = string.Format(headerFormat,
                              Uri.EscapeDataString(parameters.Nonce),
                              Uri.EscapeDataString(parameters.SignatureMethod),
                              Uri.EscapeDataString(parameters.Timestamp),
                              Uri.EscapeDataString(parameters.ConsumerKey),
                              Uri.EscapeDataString(parameters.Token),
                              Uri.EscapeDataString(parameters.Signature),
                              Uri.EscapeDataString(parameters.Version));
  }