Re: [squid-users] no-store is ignored when using squid

On Thursday 22 November 2001 11.25, Bakker, Rick wrote:
> Hello,
>
> My compagny has a website which sends the http responce header
> 'Cache-Control: no-store' with certain webpages. This all works fine
> without using squid (nothing is stored locally) but when I connect to that
> website via squid the webpages are stored locally (on my laptop, squid does
> not cache the pages).

Sounds like a browser issue. Squid preserves and honors the header.

> ** With proxy **
> Date: Thu, 22 Nov 2001 08:59:04 GMT
> Expires: Thu, 22 Nov 2001 09:29:04 GMT
> Content-Type: text/html
> Set-Cookie: PSHTTP_SESSIONID={AD340DD5-15C8-4193-AA84-BF3223D2E3F2};
> Max-Age=1200;
> Mime-Version: 1.0
> Last-Modified: Thu, 22 Nov 2001 08:59:04 GMT
> Cache-Control: no-store
> Age: 0
> X-Cache: MISS from <somewhere>
> Proxy-Connection: close
>
> Has anyone observed this behavior too and found a solution for it? Perhaps
> it's an IE 'feature', perhaps I can tweak squid, but at this time I have
> lost it :-| Thanks for the time taken!

As seen the only difference in headers are

a) Squid has added an Age: header
b) Squid has added an X-Cache: header
c) The Cache-Control header is not last.

Now, the independent ordering of headers should have no significance in HTTP,
which should rule out the difference in order.

And a Age: header tells nothing about the cachability of a responce, only how
long the object has bee "in transit" in caches etc, so the added Age header
SHOULD make no difference.. but see below.

Also, unknown headers are supposed to be silently ignored by the receiver,
which rules out the X-Cache header.

My guess is that IE upon seeing the Age: header somehow gets confused. It
should not have any significance for caching, but who knows what Microsoft
has done. IE has had problems with "Age: 0" headers in the past, completely
locking up the browser if combined with certain cache related Cache-Control
headers such as max-age=0.. so you can try upgrading Squid to a newer version
where the Age header is omitted on new obejects (Age: 0).

But it is also known that some browsers have been broken wrt the meaning of
header ordering.

Regards
Henrik Nordström

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