MVC3 OutputCache VaryByHeader=Cookie not being set

问题:

I have the following action method:

[HttpGet, Authorize, OutputCache(Duration = 60, VaryByHeader = "Cookie", Location = OutputCacheLocation.Any)]
public ActionResult Index()

But when I make a request, these are the headers issued:

Cache-Control: private, max-age=60, s-maxage=0
Content-Type: text/html; charset=utf-8
Content-Encoding: gzip
Expires: Fri, 22 Jun 2012 09:56:32 GMT
Last-Modified: Fri, 22 Jun 2012 09:55:32 GMT
Vary: Accept-Encoding

Why isn't it including the Cookie header in the Vary?

I've tried many variations of the OutputCache settings but to no avail :(

回答1:

I hate IIS almost as much as I hate ASP.NET.

http://blogs.msdn.com/b/chaun/archive/2009/10/01/iis-compression-overwrites-the-vary-header-average-rating-0-ratings.aspx

回答2:

So the response is included in the linked by Andrew Bullock url "page file name", aka "iis compression overwrites the vary header".

But since December 2013 a hotfix is available (found on Andrew Bullock link). As usual, this hotfix may be included in regular patches, so make sure you still need it before applying it.

And as it is "best practice" to explicitly supply information from links rather than only supplying the link (in case the page goes down), here is an abstract :

IIS dynamic compression overwrites the Vary header. This seems to apply to IIS from version 5 to version 8 included (when cumulating information from msdn blog and from msdn kb). Either disable IIS dynamic compression, or try applying the hotfix available at http://support.microsoft.com/kb/2877816/en-us if needed. (This issue may be fixed by regular patches on windows 8.1/2012 R2 series. The hotfix is available starting from IIS 7, personally tested on win7 sp1, not yet on my servers.)

In my specific case, I had also another issue : asp.net was not emitting any Vary header (compression enabled or not) with outputCache location set to Client. Setting it to Downstream "solved" this additional issue. But of course, this has the side-effect of changing Cache-Control from private to public. (Now cacheable on proxy instead of just on client browser.)