抛出异常时gzip/deflate失败 [英] gzip/deflate failure when an exception is thrown
问题描述
我在ASP.NET MVC 3中有一个gzip/deflate ActionFilterAttribute的有趣问题.如果我的应用程序抛出异常，而不是得到YSOD，我将看到整页的乱码，如下所示.
I have an interesting issue with a gzip/deflate ActionFilterAttribute in ASP.NET MVC 3. If an exception is thrown by my application, instead of getting a YSOD, I get a full page of gibberish as seen below.
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如果我删除了CompressAttribute，它会按预期运行(我看到了YSOD).因此，看来我的异常处理(来自Elmah.Contrib.Mvc的ElmahHandleErrorAttribute)暂停了其余的过滤器，包括CompressAttribute，并且响应未放气.
If I remove my CompressAttribute, it works as expected (I see the YSOD). So it seems that my exception handling (ElmahHandleErrorAttribute from Elmah.Contrib.Mvc) halts the remaining filters, including CompressAttribute and the response is not deflated.
相关代码:
public sealed class CompressAttribute : ActionFilterAttribute
{
private const string _acceptEncodingHeader = "Accept-Encoding";
private const string _contentEncodingHeader = "Content-Encoding";
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
HttpRequestBase request = filterContext.HttpContext.Request;
string acceptEncoding = request.Headers[_acceptEncodingHeader];
if (String.IsNullOrEmpty(acceptEncoding))
{
return;
}
acceptEncoding = acceptEncoding.ToUpperInvariant();
HttpResponseBase response = filterContext.HttpContext.Response;
if (acceptEncoding.Contains("GZIP"))
{
response.AppendHeader(_contentEncodingHeader, "gzip");
response.Filter = new GZipStream(response.Filter, CompressionMode.Compress);
}
else if (acceptEncoding.Contains("DEFLATE"))
{
response.AppendHeader(_contentEncodingHeader, "deflate");
response.Filter = new DeflateStream(response.Filter, CompressionMode.Compress);
}
}
}
过滤器注册:
GlobalFilterCollection filters = GlobalFilters.Filters;
filters.Add(new ElmahHandleErrorAttribute(), 999); // Elmah.Contrib.Mvc
filters.Add(new CompressAttribute());
即使抛出异常，如何确保响应可读?
推荐答案
这是因为当应用程序出现错误时，ASP.Net会删除所有自定义标头，但过滤器仍然存在.您可以根据应用程序错误重置过滤器，以使问题消失.
This is because when there is an error in your application ASP.Net removes all your custom headers but the filter is still there. You could reset the filter on application error that should make the problem go away.
protected void Application_Error(object sender, EventArgs e)
{
Response.Filter = null;
}
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