SPUG:CGI header question

[Peter Darley]

Brian,
	It was my assumption, born out by what Simon said, that there was some
mechanism for the browser to ask if the file has changed.  Obviously Apache
does this already and checks timestamps on files to see if it should send a
new version.
	It turns out there is a mechanism to do this, the 304 no change header and
the if-modified-since request header item.
Thanks,
Peter Darley

-----Original Message-----
From: spug-list-admin at mail.pm.org [mailto:spug-list-admin at mail.pm.org]On
Behalf Of Brian Hatch
Sent: Thursday, June 19, 2003 10:04 AM
To: Peter Darley
Cc: Aaron Salo; SPUG
Subject: Re: SPUG:CGI header question




> The problem with the expires thing is that I need to know beforehand when
> the file is going to change, and I can't know this.  The system is to
> organize pictures coming out of a digital camera, and one of the functions
> is to spin the picture 90 degrees so it's oriented correctly if the camera
> was held on it's side.  Since this could be done at any time I can't
predict
> when the image will change. :(

So, you want the browser to cache the file until it changes, but
you don't know when it's going to change.

So, how do you expect the browser to know when it'll change?  It's
obviously going to need to check each time.

Unless you're using a new "Psychic::Timestamp::Foretell" module
I don't know about.


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Brian Hatch                  It takes 43 muscles to
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