asp.net-mvc - JsonResult和ActionResult的错误处理

Question

在ASP.NET MVC 5中，我试图扩展我的站点的常规错误处理，但是我很难一次覆盖ActionResult和JsonResult。我知道JsonResult是从ActionResult转移过来的，但是当我返回ActionResult时，我只是给MVC一个View，对于JsonResult，我使用Javascript处理结果。

因此，在的情况下，其中Action的返回值是ActionResult，而Application_Error()返回JsonResult，即刚在 View 中打印的Json。在那种情况下你该怎么办？我宁愿让它重定向到错误页面或登录屏幕。我什至不知道我是否应该制作出能够处理json的javascript以便进行手动重定向的javascript，或者应该使用某些“内置” MVC机制。

在一个简化的示例中，我有两个Action's:

public ActionResult ShowPackages(PackagesViewModel packagesViewModel)
{
    var model = PackageBalhelper.GetPackageViewModel(packagesViewModel);
    return View(model);
}

[HttpPost]
public JsonResult GetDatatableRows(PackagesViewModel packagesViewModel)
{
    var jsonResult = CreateJsonResult(packagesViewModel);
    return jsonResult;
}

我到目前为止(来自 MSDN)

protected void Application_Error()
{
    HttpContext httpContext = HttpContext.Current;
    if (httpContext != null)
    {
        var requestContext = ((MvcHandler)httpContext.CurrentHandler).RequestContext;

        // When the request is ajax the system can automatically handle a mistake with a JSON response. Then overwrites the default response
        if (requestContext.HttpContext.Request.IsAjaxRequest())
        {
            httpContext.Response.Clear();
            string controllerName = requestContext.RouteData.GetRequiredString("controller");
            IControllerFactory factory = ControllerBuilder.Current.GetControllerFactory();
            IController controller = factory.CreateController(requestContext, controllerName);
            ControllerContext controllerContext = new ControllerContext(requestContext, (ControllerBase)controller);

            var jsonResult = new JsonResult
            {
                Data = new
                {
                    success = false,
                    serverError = "500"
                },
                JsonRequestBehavior = JsonRequestBehavior.AllowGet
            };
            jsonResult.ExecuteResult(controllerContext);
            httpContext.Response.End();
        }
        else
        {
            LogHelper.WriteMessageToLog("In 'Application_Error'. Not an ajax request'.");
            //httpContext.Response.Redirect("~/Error");
        }
    }
}

Answer 1

What are you supposed to do in that situation? I rather have it to redirect to errorpage or login screen.

您走在正确的轨道上。如果客户端期望服务器发出Json响应，我们绝对不希望返回View(重定向到自定义错误页面)。否则，它将破坏客户的逻辑。

此答案可能无法直接回答您的问题。但是，如果看到自己大量返回 JsonResult ，则可能要考虑在ASP.NET MVC 5中使用 Web API Controller 。

Web API 2.1支持 GlobalExceptionHandler ，您可以在其中自定义在发生未处理的应用程序期望时发送的Http响应。

就我而言，我将 Angular与ASP.NET MVC和Web API一起使用。因此，我必须为Ajax请求以Json格式返回未处理的异常。

WebApiExceptionHandler.cs

如果您的应用程序引发自定义异常，您甚至可以在此处过滤它们，并返回适当的消息。

public class WebApiExceptionHandler : ExceptionHandler
{
    public override void Handle(ExceptionHandlerContext context)
    {
        var exception = context.Exception;
        var httpException = exception as HttpException;
        if (httpException != null)
        {
            context.Result = new WebApiErrorResult(context.Request,
                (HttpStatusCode) httpException.GetHttpCode(), httpException.Message);
            return;
        }
        /*if (exception is MyCustomException)
        {
            context.Result = new WebApiErrorResult(context.Request, 
                 HttpStatusCode.NotFound, exception.Message);
            return;
        }*/
        context.Result = new WebApiErrorResult(context.Request, 
           HttpStatusCode.InternalServerError, 
          "An error occurred while processing your request.");
    }
}

WebApiErrorResult.cs

public class WebApiErrorResult : IHttpActionResult
{
    private readonly string _errorMessage;
    private readonly HttpRequestMessage _requestMessage;
    private readonly HttpStatusCode _statusCode;

    public WebApiErrorResult(
        HttpRequestMessage requestMessage,
        HttpStatusCode statusCode,
        string errorMessage)
    {
        _requestMessage = requestMessage;
        _statusCode = statusCode;
        _errorMessage = errorMessage;
    }

    public Task<HttpResponseMessage> ExecuteAsync(CancellationToken cancellationToken)
    {
        return Task.FromResult(_requestMessage.CreateErrorResponse(_statusCode, _errorMessage));
    }
}

WebApiConfig.cs

最后，我们向框架注册我们的自定义异常处理程序。

public static class WebApiConfig
{
    public static void Register(HttpConfiguration config)
    {
        config.MapHttpAttributeRoutes();

        config.Routes.MapHttpRoute(
            name: "DefaultApi",
            routeTemplate: "api/{controller}/{id}",
            defaults: new { id = RouteParameter.Optional });

        config.Services.Replace(typeof(IExceptionHandler), new WebApiExceptionHandler());

        config.Filters.Add(new AuthorizeAttribute());
    }
}