/// <summary>
        /// 测试业务异步回调接口是否正确
         /// </summary>
        /// <param name="notifyUrl">业务服务地址</param>
        /// <returns></returns>
        [HttpPost]
        [Route("notify")]
        public async Task<IHttpActionResult> PostJsonAsync(string notifyUrl)
        {
            if (notifyUrl.IsNullOrEmpty() || !notifyUrl.Contains("http", StringComparison.OrdinalIgnoreCase)) return Ok(new { IsError = true, Msg = "NotifyUrl IS EMPTY", Data = string.Empty });
            //notifyUrl = notifyUrl.UrlDecode(System.Text.Encoding.UTF8);
            var payPal = new PayPalData
            {
                UserID = "test",
                Subject = "测试异步回调接口",
                OutTradeNO = "10086",
                CreateTime = DateTime.Now,
                GuidNO = Guid.NewGuid().ToString(),
                TotalFee = "0.01",
                Origin = "WEB"
            };
            try
            {
                var data = await notifyUrl.PostJsonAsync(payPal).ReceiveJson<WebAPIResponse>();
                logger.Info("PayPalController JsonAsync : " + payPal.SerializeJson(System.Text.Encoding.UTF8));
                if (data.IsError)
                {
                    return Ok(new { IsError = true, Msg = data.Msg, Data = data.Data });
                }
                return Ok(new { IsError = false, Msg = string.Empty, Data = payPal.SerializeJson(System.Text.Encoding.UTF8) });
            }
            catch (Exception ex)
            {
                return Ok(new { IsError = true, Msg = "PostJsonAsync Exception : " + ex.Message, Data = payPal.SerializeJson(System.Text.Encoding.UTF8) });
            }
        }

/// <summary>
    /// http://www.asp.net/web-api/overview/formats-and-model-binding/model-validation-in-aspnet-web-api
    /// http://www.asp.net/web-api/overview/error-handling/exception-handling
    /// </summary>
    public class ModelValidFilter : ActionFilterAttribute
    {
        /// <summary>
        /// 模型验证
        /// </summary>
        /// <param name="actionContext"></param>
        /// <param name="cancellationToken"></param>
        /// <returns></returns>
        public override Task OnActionExecutingAsync(HttpActionContext actionContext, System.Threading.CancellationToken cancellationToken)
        {
            if (actionContext.ActionArguments.Values.FirstOrDefault().IsNull())
            {
                var data = new { IsError = true, Msg = "参数不能为空！", Data = string.Empty };
                actionContext.Response = actionContext.Request.CreateResponse(HttpStatusCode.OK, data);
                return base.OnActionExecutingAsync(actionContext, cancellationToken);
            }
            if (!actionContext.ModelState.IsValid)
            {
                // 注意 !!!!： http://tmenier.github.io/Flurl/fluent-http/ HttpStatusCode.BadRequest 
                var data = new { IsError = true, Msg = actionContext.ModelState.Values.FirstOrDefault().Errors.FirstOrDefault().ErrorMessage, Data = actionContext.ModelState.Keys.FirstOrDefault() + " :参数验证有误！！！" };
                actionContext.Response = actionContext.Request.CreateResponse(HttpStatusCode.OK, data);
                return base.OnActionExecutingAsync(actionContext, cancellationToken);
            }
            return base.OnActionExecutingAsync(actionContext, cancellationToken);
        }
    }