Re: [squid-users] caching for 60 minutes, ignoring any header

Hi Amos,

Thanks for your thorough response.
Please refer to my response to Eliezer.

Thanks!

On 23-Sep-13 07:29, Amos Jeffries wrote:
> On 23/09/2013 3:01 p.m., Ron Klein wrote:
>> Hi,
>>
>> I'm trying to cache all favicons files, named favicon.ico, located
>> always in the root of the web site (when they exist, of course)
>> I would like to ignore any caching instruction originates from the
>> (real) web server response headers.
>> For instance, if I get the "last modified" header, I'd like to ignore
>> it.
>> I want the caching policy to be purely "mine".
>
> FYI: Last-Modified is not caching policy. It is a timestamp telling
> when the object was last changed. *Your* caching policy relies on such
> details in order to calculate age teh same as teh default ones do.
>
> And no there is no way to replace the caching features of HTTP with
> your own. All Squid does is allow you to tune the parameters used by
> the algorithm.
>
>
>>
>> I use Squid 3 on Ubuntu 12.04 .
>> I created the following instruction in the configuration file:
>> refresh_pattern -i ^http(s?)://.*/favicon.ico$ 60 0% 60
>> ignore-private override-expire override-lastmod ignore-no-store
>
> Erm...
>
> "ignore-no-store" makes everything which is forbidden to be cached go
> into the storage.
> NOTE: no-store on a favicon is usually only done on private
> company internal sites where the entire domain or subdomain (its
> existence even) is legally privilaged information.
>
> "ignore-private" makes Squid ignore the privacy restrictions on marked
> content and deliver the per-user content to all users.
> NOTE: private content *can* be cached by Squid. It is the ability
> to send one users private data to another user which is enabled by
> this option.
> Consider that the favicon is sometimes used for ever-cookie style
> tagging of users or signalling of persistent authentication states.
> You just caused any server doing that to send the wrong signals to the
> wrong users.
>
> "override-lastmod" makes Squid ignore the Last-Modified timestamp when
> applying caching policy.
> NOTE: without a last modified timestamp the caching policy is fed
> the Date header on the transaction. Effectively everything is less
> than 1 second old.
>
> "override-expires" makes Squid ignore the Expires: header on the
> response when applying caching policy.
> NOTE: without expiry timestamp the object *never* expires.
>
>>
>> My question:
>> Is this the correct instruction? I think not, since I get "HIT"
>> response headers even after one hour of caching.
>
> Are HITs somehow bad? note that HIT is not related to FRESH/STALE in
> HTTP/1.1. It just means the cached object is *able* to be sent to the
> client immediately.
>
> You can set debug_options 22,3 to get a trace of the refresh algorithm
> tests and reasons about a response FRESH/STALE.
>
> Amos
Received on Mon Sep 23 2013 - 07:23:55 MDT