I have a slow backend application that I’m using nginx to provide
the authentication and caching for. It’s been working great however
there
is one nagging issue that I cannot seem to resolve, when the backend app
sets a s-maxage and a maxage Cache-Control, nginx only seems to honor
the
maxage and expires the cache with its value.
An example response from the backend is like this…
Cache-Control: max-age=60, s-maxage=3600, public, must-revalidate
My idea here is I only want the client to cache this data for a short
amount of time before checking in with me it see if it’s still valid.
The
data usually wont be changing that often so I want nginx to cache it for
an
hour, but in the event it does I use the excellent nginx-cache-purge
script
in my backend app to invalidate the cache and the next time a client
checks
in (after 60 seconds) they will get the new data.
However in all my testing and usage I will only get a cache HIT for 60
seconds after the first request to a resource, after 60 seconds it will
be
EXPIRED then it will go to the backend again. Am I missing something in
the Cache-Control that is causing this behavior?
–
Ryan P.ish
Hello!
On Tue, Apr 23, 2013 at 11:05:58AM -0400, Ryan P.ish wrote:
amount of time before checking in with me it see if it’s still valid. The
data usually wont be changing that often so I want nginx to cache it for an
hour, but in the event it does I use the excellent nginx-cache-purge script
in my backend app to invalidate the cache and the next time a client checks
in (after 60 seconds) they will get the new data.
Note: you will not be able to purge shared chaches outside of your
control, so this might not work as you expect.
However in all my testing and usage I will only get a cache HIT for 60
seconds after the first request to a resource, after 60 seconds it will be
EXPIRED then it will go to the backend again. Am I missing something in
the Cache-Control that is causing this behavior?
As of now nginx doesn’t handle s-maxage.
Trivial solution is to use X-Accel-Expires to specifi expiration
time for your nginx cache. This should also better match a use
case you’ve described (as it will only ask your nginx cache to
cache longer, not all shared caches in the world).
–
Maxim D.
On Wed, Apr 24, 2013 at 7:41 AM, Maxim D. [email protected]
wrote:
in my backend app to invalidate the cache and the next time a client
the Cache-Control that is causing this behavior?
As of now nginx doesn’t handle s-maxage.
Trivial solution is to use X-Accel-Expires to specifi expiration
time for your nginx cache. This should also better match a use
case you’ve described (as it will only ask your nginx cache to
cache longer, not all shared caches in the world).
That worked perfectly, thank you!
–
–
Ryan P.ish
Chief Technologist, Member
CoreLogic LLC
M: (408)966-4673
solutions for the extended enterprise