Re: [squid-users] Technical question...

From: Marc van Selm <>
Date: Thu, 08 Nov 2001 09:41:54 +0100

At 08:42 AM 11/8/01 +0100, Boniforti Flavio wrote:
>I got this situation:
>I opened a site with my client, so it has been cached. Then I updated that
>site (I'm the maintainer) and changed a picture in it. The picture has the
>same filename, but different size.
>As I reopened the same site on another client, I was looking at the OLD
>picture... How come???

In Squid's refresh rules you can configure a minimal time that a cached
file is "fresh". You will find a minimal time, a figure based on the last
modified-time and a maximum. If the web server does not provide an
"expires" header, Squid relies on these parameters. Only when the minimal
fresh time is passed an If-modified-since request is done.

What to do:
1) Do not worry and configure Squid to keep files in the cache "fresh" for
at least x minutes. I take this approach because bandwidth saving and
increased average download speed has preference in my environment.
2) Reduce the refresh rules so that a IMS check is done quicker. The
penalty will be increased response time.
3) Control the cache time with a "expires" header from the web-server.

>As I did a RELOAD on IE5.5 nothing happened, I had to FORCE a RELOAD (with
>SHIFT+RELOAD button)...
>The main question is: how do I force the squid to actually reload stuff,
>acting from a client???
>Thanx in advance, and if I wasn't clear enough I'll try to do better!
>Boniforti Flavio
>Informa Srl
>Via 42 Martiri, 165
>28924 Verbania (VB)
>Tel +39 0323 586216
>Fax +39 0323 586672

Marc van Selm
NATO C3 Agency, CIS/CaN

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Received on Thu Nov 08 2001 - 01:41:57 MST

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