On 2014-08-23 17:43, Mark Montague wrote:
> - Back-end sets response header "Cache-Control: max-age=0,
s-maxage=14400" so that mod_cache
> caches the response, but ISP caches and browser caches do not.
(mod_cache removes s-maxage
> and does not pass it upstream).
mod_cache shouldn’t remove any Cache-Control headers.
It apparently does, although I haven't found where in the code yet. I
would be interested to see if anyone can reproduce my experience. As
far as I know, I don't have any configuration that would result in this.
Please ignore this part of my previous reply, I found out what was going on:
When the content is first requested, mod_cache has a miss and it stores
the content. But when it sends it on to the client, it does so without
any Cache-control header at all:
GET /test.php HTTP/1.1
Host: dev.catseye.org
HTTP/1.1 200 OK
Date: Sat, 23 Aug 2014 22:01:26 GMT
Server: Apache/2.4
X-Cache: MISS from dev.catseye.org
X-Cache-Detail: "cache miss: attempting entity save" from dev.catseye.org
Transfer-Encoding: chunked
Content-Type: text/html;charset=UTF-8
The second time the resource was requested, it is served by mod_cache
from the cache with the original Cache-Control header (I added "foo=1"
to the header track this when I generated the page):
GET /test.php HTTP/1.1
Host: dev.catseye.org
HTTP/1.1 200 OK
Date: Sat, 23 Aug 2014 22:02:21 GMT
Server: Apache/2.4
Cache-Control: max-age=0, foo=1, s-maxage=14400
Content-Security-Policy: default-src 'self'; script-src 'self'
'unsafe-inline' 'unsafe-eval'; style-src 'self' 'unsafe-inline'; img-src
'self' data: ; font-src 'self' data: ; report-uri /csp-report.php
Age: 54
X-Cache: HIT from dev.catseye.org
X-Cache-Detail: "cache hit" from dev.catseye.org
Content-Length: 33
Content-Type: text/html;charset=UTF-8
What was happening was that led me to assume that mod_cache was
"editing" the header (which, I now see, it wasn't) was because I had the
following directives that escaped my attention when I was composing my
previous reply:
ExpiresActive on
ExpiresDefault "access plus 1 week"
ExpiresByType text/html "access plus 0 seconds"
This resulted in a "Cache-control: max-age=0" header being
unconditionally added to the response headers, even if another header
was already there. So for a cache miss, I would see:
Cache-control: max-age=0
while for a cache hit I would see
Cache-control: max-age=0
Cache-Control: max-age=0, foo=1, s-maxage=14400
Mystery solved. I apologize for the red herring and waste of people's
time and attention.
I'm still looking for a solution to the original problem: how to
indicate to mod_cache that cached content for a particular URL path
should be served to some clients (ones without login cookies), but not
to other clients (ones with login cookies).
--
Mark Montague
m...@catseye.org
