c# - 如何结束响应并发回 HTTP 代码 404？

Question

我正在使用温莎城堡工厂根据请求 url 实例化一个对象。

类似于:

    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，我实际上想抛出 404 并停止请求，目前如:

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

但是请求并没有结束，它仍然点击 Action 并尝试解析 View ？

我的 Controller 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();
    }

我是不是想错了？或者有什么方法可以实现这一点？

我正在考虑的替代方案是检查 Foo 属性状态的操作属性？

Answer 1

我认为使用 Action 过滤器的方法可以实现您想要的:

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 Controller 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处理任何抛出的 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());
  }