用mod_expires覆盖缓存头(Overwrite cache-headers with mod_expires)

 我想使用apache的mod_expires模块设置缓存头。 我的配置看起来有点像这样： 
 
<LocationMatch ^/static >
    ExpiresDefault "access plus 1 years"
</LocationMatch>
 
 问题是，这些文件是由我不控制的第三个系统生成的。 这些系统为文件提供以下标题： 
 
Date Mon, 24 Oct 2011 08:39:02 GMT
Cache-Control no-cache,no-store,must-revalidate
Pragma no-cache
Expires Thu, 01 Dec 1994 16:00:00 GMT
 
 这些标头使得不可能使用mod_expires设置缓存标头。 http://httpd.apache.org/docs/2.2/mod/mod_expires.html告诉我们为什么： 
 
 
 
 当Expires头已经是服务器产生的响应的一部分时，例如当由CGI脚本产生或从源服务器代理时，这个模块不会改变或添加Expires或Cache-Control头。 
 
 
 有没有什么可能的方法来绕过这个规则，并用mod_expires覆盖头文件？ 
 
 更新：一种可能的解决方案，为了避免这种限制，只能使用mod_headers来设置缓存头。 不幸的是，这不是一种替代方案，因为必须计算这些值。 
 
 感谢它的进步。 

I want to set cache-headers using the mod_expires module from apache. My configuration looks somewhat like this:
 
<LocationMatch ^/static >
    ExpiresDefault "access plus 1 years"
</LocationMatch>
 
The problem is, that the files are generated by a third system I don't control. These system provides files with the following headers:
 
Date Mon, 24 Oct 2011 08:39:02 GMT
Cache-Control no-cache,no-store,must-revalidate
Pragma no-cache
Expires Thu, 01 Dec 1994 16:00:00 GMT
 
These headers makes it impossible to set the cache-headers with mod_expires. http://httpd.apache.org/docs/2.2/mod/mod_expires.html tells us why:
 
 
 
When the Expires header is already part of the response generated by the server, for example when generated by a CGI script or proxied from an origin server, this module does not change or add an Expires or Cache-Control header.
 
 
Is there any possible way to circumvent this rule and overwrite the headers with mod_expires?
 
Update: One possible solution, to avoid this limitation is to use only mod_headers to set the cache-headers. Unfortunately, this isn't an alternative because the values have to be calculated.
 
Thanks it advance.

原文：https://stackoverflow.com/questions/7930140