如何在 Asp.Net-MVC 中添加自定义 HTTP 标头

我创建了一个自定义处理程序，如下所示：

public class SitHandler : DelegatingHandler
{
    protected override async Task<HttpResponseMessage> SendAsync(
        HttpRequestMessage request, CancellationToken cancellationToken)
    {
        Debug.WriteLine("Process request");
        // Call the inner handler.
        var response = await base.SendAsync(request, cancellationToken);
        Debug.WriteLine("Process response");
        return response;
    }
}

并在班级中注册WebApiConfig:

public static class WebApiConfig
{
    public static void Register(HttpConfiguration config)
    {
      // Web API configuration and services

      //Delegating Handlers
      config.MessageHandlers.Add(new SitHandler());

      // Web API routes
      config.MapHttpAttributeRoutes();

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

并有以下路线：

[RoutePrefix("")]
public class SignInController : Controller
{
    [Route("", Name = "Default")]
    public ActionResult Index()
    {
      return View();
    }
}

Now when I start the server it show me the correct page as expected:

但请求并没有经过处理程序，为什么？
什么是内部处理程序？

// Call the inner handler.
var response = await base.SendAsync(request, cancellationToken);

对于 MVC，您需要添加一个ActionFilterAttribute

[AttributeUsage(AttributeTargets.Method | AttributeTargets.Class, AllowMultiple = false, Inherited = true)]
public class MyCustomFilter : System.Web.Mvc.ActionFilterAttribute {
    public override void OnActionExecuted(ActionExecutedContext context) {
        Debug.WriteLine("Process response");
        //From here you have access to the response to process what you need
        //eg: context.HttpContext.Response.Headers.Add("MyCustomHeaderName","value");

        base.OnActionExecuted(context);
    }
}

然后您可以在操作上使用您的属性...

[MyCustomFilter]
[Route("", Name = "Default")]
public ActionResult Index(){...}

， 班级...

[MyCustomFilter]
[RoutePrefix("")]
public class SignInController : Controller {...}

，或全局设置...

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