すべての HTTP リクエストを POST に制限するにはどうすればよいですか?

public class HomeController : Controller
 { 
 [HttpPost]
 public ActionResult Index()
 {
  return View();
 }
 }

//
 // 摘要:
 // 表示一个特性，该特性用于限制操作方法，以便该方法仅处理 HTTP POST 请求。
 [AttributeUsage(AttributeTargets.Method, AllowMultiple = false, Inherited = true)]
 public sealed class HttpPostAttribute : ActionMethodSelectorAttribute
 {

 }

public class HttpMethodModule : IHttpModule
 {
 public void Init(HttpApplication context)
 {
  context.PostMapRequestHandler += Context_PostMapRequestHandler;
 }

 private void Context_PostMapRequestHandler(object sender, EventArgs e)
 {
  HttpApplication httpApplication = (HttpApplication) sender;
  HttpContext httpContext = httpApplication.Context;


  //判断当前是否使用的是 MVC 框架来处理请求，其它的请示不做控制。
  MvcHandler mvcHandler = httpContext.Handler as MvcHandler;

  if (mvcHandler != null && httpContext.IsPostMethod() == false) {
  throw new HttpException(404, "访问的资源不存在。");
  }
 }

 public void Dispose()
 {

 }
 }

<?xml version="1.0" encoding="utf-8"?>
<configuration>
 <system.webServer>
 <modules>
 <add name="HttpMethod" type="HttpPostWebApp.Web.HttpMethodModule, HttpPostWebApp"/>
 </modules>
 </system.webServer>
</configuration>

public class HttpPostFilter : IAuthorizationFilter
 {
 public void OnAuthorization(AuthorizationContext filterContext)
 {
  if (filterContext.HttpContext.IsPostMethod() == false) {

  //如果不是POST请求，则返回404。
  filterContext.Result = new HttpNotFoundResult();
  }
 }
 }

public class FilterConfig
 {
 public static void RegisterGlobalFilters(GlobalFilterCollection filters)
 {
  filters.Add(new HttpPostFilter());
 }
 }

public class RouteConfig
 {
 public static void RegisterRoutes(RouteCollection routes)
 {
  routes.MapRoute(
  name: "Default",
  url: "{controller}/{action}/{id}",
  defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional }
  //限制请求方式必须是POST
  , constraints:new { httpMethod = new HttpMethodConstraint("POST")}
  );
 }
 }

public abstract class BaseController : Controller
 {
 protected override void OnActionExecuting(ActionExecutingContext filterContext)
 {
  
  if (filterContext.HttpContext.IsPostMethod() == false) {
  //如果不是POST请求，则返回404。
  filterContext.Result = new HttpNotFoundResult();
  }
  else {
  base.OnActionExecuting(filterContext);
  }
 }
 }