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From Simon Mott <>
Subject Re: [users@httpd] mod_cache, mod_deflate, mod_expires and a headache
Date Fri, 03 Jun 2016 20:04:44 GMT
Hi All

Still struggling with this one :)

I've tried adding "MOD_EXPIRES" as a filter before "CACHE" but it doesn't
seem to cause mod_expires to be evaluated before its cached (I don't really
understand what AP_FTYPE_CONTENT_SET-2 means in the source for mod_expires)
- Can what I'm trying to do be done?

Essentially, I am trying to achieve something like:

> # Apply mod_expires config to all output BEFORE hitting mod_cache - Then
cache the output
> # Doing this ensures correct cache control headers are in place by
mod_expires prior to mod_cache doing its thing
>  SetOutputFilter MOD_EXPIRES;CACHE
> # pass through mod_deflate after everything else is done for text content
>  AddOutputFilterByType DEFLATE text/html text/plain text/css
application/javascript application/rss+xml

Kind Regards,

On 1 June 2016 at 19:41, Simon Mott <> wrote:

> Hi Eric
> Thanks for getting back to me. So if there is no mime type when it wants
> to cache which is why the AddOutputFilterType CACHE filter isn't doing what
> I expect, but SetOutputFilter CACHE gets caching before compression
> correct, is there any way I can apply mod_expires and mod_headers before
> passing to be cached also? This ensures that correct cache control headers
> are used prior to being dealt with by mod_cache
> Currently with:
> >  SetOutputFilter CACHE
> >  AddOutputFilterByType DEFLATE text/html text/plain text/css
> application/javascript application/rss+xml
> output is being cached BEFORE mod_expires adds its headers so its not
> adhering to content expiry times.
> Essentially I want Apache to do everything it needs to in order to
> generate content (uncompressed, so as to not maintain multiple copies of
> content based on the "Vary" header), then cache it and finally gzip it
> before it goes out if the client supports gzip via mod_deflate
> Is this something that can be achieved or does it require modification of
> modules?
> Thanks
> On 1 June 2016 at 16:34, Eric Covener <> wrote:
>> I think the absence of AH00758 in the AddOutputFilterByType case is
>> due to no mimetype being available early enough in processing to allow
>> "CACHE" to be replaced by the actual caching filters when mod_cache
>> wants to do it.  It makes sense that no types would be available in
>> the early "handler" mod_cache uses to both serve from the cache and
>> setup caching when there's a miss.
>> Sounds like the doc needs improvement.
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