Api key verify Handler

APIKeyHandler.cs

 /// <summary>
    /// Verify that all request to api must contain apikey
    /// </summary>
    public class APIKeyHandler : DelegatingHandler
    {
        private string APIToken = "apiKey";

        protected override System.Threading.Tasks.Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, System.Threading.CancellationToken cancellationToken)
        {
            if (request.Method == HttpMethod.Options) goto success;

            var apiKey = request.GetQueryString(APIToken);
            if (!string.IsNullOrEmpty(apiKey)) goto verifyKey;

            IEnumerable<string> availableHeaders = null;

            if (!request.Headers.TryGetValues(APIToken, out availableHeaders))
                return request.ApiKeyMissingExpetion();

            if (availableHeaders.Count() > 1)
                return request.MulitpleKeyProvideException();

            apiKey = availableHeaders.First();

        verifyKey:
            if (!Config.APIKEYS.ContainsKey(apiKey))
                return request.InvalidApikeyException();

            var deviceType = Config.APIKEYS[apiKey];
            var secretKey = Config.APIKEYSECRET[apiKey];
            request.Headers.Add("DeviceType", deviceType);
            request.Headers.Add("secret", secretKey);
        success:
            return base.SendAsync(request, cancellationToken);
        }
    }

WebApiConfig.cs

  public static class WebApiConfig
  {
      public static void Register(HttpConfiguration config)
      {
            #region Global Handler

            config.MessageHandlers.Add(new APIKeyHandler());

            #endregion Global Handler
      }
  }