public override void OnAuthorization(HttpActionContext actionContext)
 {
     try
     {
         if (Authorize(actionContext))
         {
             return;
         }
         HandleUnauthorizedRequest(actionContext);
     }
     catch (Exception)
     {
         PetWhizzResponse IGResponse = new PetWhizzResponse()
         {
             Message    = "Token Expired",
             Code       = (Int32)ErrorCode.TOKENEXPIRED,
             Object     = null,
             ObjectType = null
         };
         actionContext.Response = actionContext.Request.CreateResponse(
             HttpStatusCode.OK,
             IGResponse
             );
         return;
     }
 }
        protected override void HandleUnauthorizedRequest(HttpActionContext actionContext)
        {
            //create custom unauthorized exception
            PetWhizzResponse IGResponse = new PetWhizzResponse()
            {
                Message    = "Unauthorized Call",
                Code       = (Int32)ErrorCode.UNAUTHORIZED,
                Object     = null,
                ObjectType = null
            };

            actionContext.Response = actionContext.Request.CreateResponse(
                HttpStatusCode.OK,
                IGResponse
                );
            return;
        }