Question

我们正在开发新的MVC5网络应用程序，我们正在使用现有的API库来实现某些功能。

现在，这些API库会抛出某些需要传回客户端浏览器的异常类型。

我希望如何处理这些例外：

如果被调用的操作返回一个视图，则将用户带到一个带有异常消息的页面
如果被调用的操作返回JSON字符串，则以字符串格式

我现在关注的是＃2，因为控制器的'OnException'方法总是返回服务器错误，默认情况下ASP.NET将返回默认的自定义错误，除非我按如下方式更改Web应用程序配置

<system.web> 
...
  <customErrors mode="Off"/>
<system.webServer>
...
   <httpErrors errorMode="Detailed" />

我的问题是，如何从“OnException”返回JSON字符串而不必更改上面显示的Web配置？（即，提升ExceptionContext以返回常规JSON响应字符串）。

TIA

protected override void OnException(ExceptionContext filterContext)
    {
        //If the exeption is already handled we do nothing
        if (filterContext.ExceptionHandled)
        {
            return;
        }

        // Init
        var vm = new ExceptionViewModel();
        Exception ex = filterContext.Exception;
        var controllerName = filterContext.RouteData.Values["controller"].ToString();
        var actionName = filterContext.RouteData.Values["action"].ToString();

        // Get action return type
        Type controllerType = filterContext.Controller.GetType();
        var method = controllerType.GetMethod(actionName);
        Type returnType = null;

        // If method is null, default to JSONREsult
        if (method == null)
        {
            returnType = typeof(JsonResult);
        }
        else
        {
            returnType = method.ReturnType;
        }

        // Log exception
        vm.ErrorLogId = LogException(ex);

        // Assign Exception View Model
        if (ex is MyCustomExceptionType)
        {
            filterContext.HttpContext.Response.StatusCode = 200;
            vm.ErrorMessage = filterContext.Exception.Message;
        }
        else if (ex is NotAuthorizedException)
        {
            // Get Http exception
            var httpEx = ex as NotAuthorizedException;
            filterContext.HttpContext.Response.StatusCode = httpEx.GetHttpCode();
            vm.ErrorMessage = httpEx.Message;
        }
        else
        {
            // Set status code to 500 since this exception block indicates an application
            // exception occurred
            filterContext.HttpContext.Response.StatusCode = 500;
            vm.ErrorMessage = "Sorry, I may have malfunctioned. Toink!";
        }

        // Prepare data to return back to client
        if (returnType.Equals(typeof(JsonResult)) || returnType.Equals(typeof(Task<JsonResult>)))
        {
            filterContext.Result = new JsonResult()
            {
                Data = vm.ErrorMessage,
                JsonRequestBehavior = JsonRequestBehavior.AllowGet
            };
        }
        else
        {
            filterContext.Result = new ViewResult()
            {
                ViewName = "Error",
                ViewData = new ViewDataDictionary(vm)
            };
        }

        // Mark exception as a handled
        filterContext.ExceptionHandled = true;
    }

ASP.NET MVC - 使ExceptionContext返回正常响应

0 个答案: