如何结束响应并发回HTTP代码404？

Question

我正在使用城堡windsor工厂根据请求网址实例化一个对象。

就像是：

    public FooViewModel Get()
    {
        if (HttpContext.Current == null)
        {
            return new FooViewModel();
        }

        var currentContext = new HttpContextWrapper(HttpContext.Current);

        // resolve actual view model.

在某些情况下，我实际上想要抛出404并停止请求，目前如下：

        throw new HttpException(404, "HTTP/1.1 404 Not Found");
        currentContext.Response.End();

但是请求没有结束，它仍然命中Action并尝试解析视图？

我的控制器看起来像这样：

public class HomeController : Controller
{
    public FooViewModel Foo { get; set; }

    public ActionResult Index()
    {
        ViewBag.Message = "Modify this template to jump-start your ASP.NET MVC application.";

        return View();
    }

我觉得这一切都错了吗？ 或者有没有办法实现这一目标？

我想到的另一种选择是检查Foo属性状态的动作属性？

Answer 1

我认为使用动作过滤器的方法可以达到你想要的效果：

public class RequiresModelAttribute : ActionFilterAttribute
{
    private readonly string _modelName;

    public RequiresModelAttribute(string modelName)
    {
        _modelName = modelName;
    }

    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        var property = filterContext.Controller.GetType().GetProperty(_modelName);
        var model = property.GetValue(filterContext.Controller);
        if (model == null)
        {
            filterContext.Result = new HttpStatusCodeResult(404);
        }
    }
}

然后，在您的控制器上，您可以：

public class HomeController : Controller
{
    public FooViewModel Foo { get; set; }

    [RequiresModel("Foo")]
    public ActionResult Index()
    {
        ViewBag.Message = "Modify this template to jump-start your ASP.NET MVC application.";

        return View();
    }
}

编辑：也许使用全局过滤器来兑现任何抛出的HttpExceptions？

public class HonorHttpExceptionAttribute : ActionFilterAttribute
{
    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        var httpException = filterContext.HttpContext.AllErrors.FirstOrDefault(x => x is HttpException) as HttpException;
        if (httpException != null)
        {
            filterContext.Result = new HttpStatusCodeResult(httpException.GetHttpCode());
        }
    }
}

然后在Global.asax中：

  public static void RegisterGlobalFilters(GlobalFilterCollection filters)
  {
      filters.Add(new HandleErrorAttribute());
      filters.Add(new HonorHttpExceptionAttribute());
  }

Answer 2

另一个选项是覆盖Controller上的OnException。

 public ActionResult Index()
    {
        ViewBag.Message = "Welcome to ASP.NET MVC!";
        Get();
        return View();
    }

    public int Get()
    {
        throw new HttpException(404, "HTTP/1.1 404 Not Found");
        // we don't need end the response here, we need go to result step
        // currentContext.Response.End();

    }

    protected override void OnException(ExceptionContext filterContext)
    {
        base.OnException(filterContext);
        if (filterContext.Exception is HttpException)
        {
            filterContext.Result = this.HttpNotFound(filterContext.Exception.Message);
        }
    }