Re: [squid-users] bug? (was "cache deny and the 'public' token")

From: Henrik Nordstrom <hno@dont-contact.us>
Date: Tue, 25 Mar 2008 11:19:25 +0100

On Mon, 2008-03-24 at 11:44 -0700, Ric wrote:
> Yes, I realize this. Unless we authenticate using one of the
> Authenticated header methods, it seems that we have to be careful not
> to try caching "split views" in standard proxies.

Even then you have the same problem. A public response is a cache hit
even if the request carries authentication.

> Cookie-
> authenticated responses should only be cacheable in public shared
> caches if they contain no personalization.

Which is quite doable if such requests do not have any personal cookie
at all (not even a tracker one), but fails if there is any kind of
session/tracker cookie making each user unique.

If there is no user/session/tracking specific cookie on public requests
then send

Vary: Cookie

and additionally on personalized content

Cache-Control: private

"Vary: Cookie" says that this response varies with the content of the
Cookie header. That is every little bit of it, not just some cookie or
the servers state depending on a specific cookie, any change in cookie
contents means a unique request..

"Cache-Control: private" says that this response is private and intended
for a single user only.

Regards
Henrik
Received on Tue Mar 25 2008 - 04:27:57 MDT

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