W3C home > Mailing lists > Public > http-caching-historical@w3.org > February 1996

Variant IDs

From: Daniel DuBois <ddubois@rafiki.spyglass.com>
Date: Fri, 2 Feb 1996 18:26:44 -0600
Message-Id: <9602030026.AA00501@rafiki.spyglass.com>
To: http-caching@pa.dec.com

One thing I didn't understand from the phone conference was the fact that
there seemed to be objections with variant IDs equaling cache-validator IDs?
Is this true?

Maybe my problem is I'm working from the assumption people will make
almost-always unique 'Content-IDs' as their validator, and others are
working from the assumption that most servers will make Cache-Validator:
equal Date:, and be using validating algorithms other than equal (like
greater than)?

While I'm here I want to reemphasize (because we spent so much time talking
about Vary: issues) that I believe URI: is the way to go for most content
negotiation.  Additionally, if the URI: scheme is used, the whole point of
the proxy server providing the origin server with a list of variantIDs is
moot, because the proxy server doesn't have to provide such a list anymore.
<BROKEN-RECORD>It can do its own computations, and know, by URL, which
variant it wants, possibly completely saving a RTT with the origin server if
that URL is in cache.  Vary: is strictly for the evil case that would
otherwise be a "Cache-control: no-cache". </BROKEN-RECORD>

Dan DuBois, Software Animal           http://www.spyglass.com/~ddubois/
    Download a totally free copy of the Spyglass Web Server today!
Received on Saturday, 3 February 1996 00:53:01 UTC

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