ASP.NET MVC - 在RegisterGlobalFilters()中使用ActionFilterAttribute时,Response.Filter为null

Question

我想在我的网站上使用G-ZIP,我用Google搜索了以下代码:

public class CompressAttribute : ActionFilterAttribute
{
    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        var acceptEncoding = filterContext.HttpContext.Request.Headers["Accept-Encoding"];
        if (!string.IsNullOrEmpty(acceptEncoding))
        {
            acceptEncoding = acceptEncoding.ToLower();
            var response = filterContext.HttpContext.Response;
            if (acceptEncoding.Contains("gzip"))
            {
                response.AppendHeader("Content-encoding", "gzip");
                response.Filter = new GZipStream(response.Filter, CompressionMode.Compress);
            }
            else if (acceptEncoding.Contains("deflate"))
            {
                response.AppendHeader("Content-encoding", "deflate");
                response.Filter = new DeflateStream(response.Filter, CompressionMode.Compress);
            }
        }
    }
}

当我将属性设置为Controller或Action时,它工作正常.

[Compress]
public class PostController : Controller

我不想在每一段代码上都这样做,所以我在这里注册了这个属性

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

但是当我运行应用程序时,这行代码出现异常:

response.Filter = new GZipStream(response.Filter, CompressionMode.Compress);

response.Filter为null.

我想知道为什么会这样,以及如何解决这个问题.谢谢!

- 更新:

我发现仅当控制器包含子操作并且正在调用它时才会发生异常.

Answer 1

我的解决方案是过滤所有儿童行为.

if (filterContext.IsChildAction) return;

在方法的顶部使用此代码.

public class CompressAttribute : ActionFilterAttribute
{    
   public override void OnActionExecuting(ActionExecutingContext filterContext)
   {
       if (filterContext.IsChildAction) return;

       ...
    }
}