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Re: Conventions for Sharing User Agent Profiles

From: Koen Holtman <koen@win.tue.nl>
Date: Tue, 13 Aug 1996 00:57:23 +0200 (MET DST)
Message-Id: <199608122257.AAA20923@wsooti04.win.tue.nl>
To: "David W. Morris" <dwm@shell.portal.com>
Cc: dsr@w3.org, http-wg%cuckoo.hpl.hp.com@hplb.hpl.hp.com
David W. Morris:
>
>The difficulty I believe is in the codification of features in a way that
>will satisfy everybody (or mostbodies).

This is a very general problem.  Quoting from the Montreal minutes:

 Harald Alvestrand pointed out that the group does not have a unified
 model; we have a desire to create a language to describe what the user
 wants and a language to describe what the server has and we don't have
 a unified model for bringing those together; until that model comes
 together--neither is going forward.

As far as I know, the only complete specification of such unified
languages is in the transparent content negotiation draft.  One of
these languages (Accept headers including Accept-Features) could be
used for user agent profiles.

I'm always wondering if (transparent) content negotiation can't be
made simpler, and the idea of using the power of indirection to
simplify the negotiation process is exciting.  But sadly I can't see a
way to use this power to simplify the whole thing (yet).

[....]
>Finally there are a whole bunch of characteristics which describe an
>individual installation of a browser product which I believe Koen has
>already noted should fit well under content negotiation.

Yes, I see this as the main problem with UA profiles: they cannot
contain _all_ preferences and capabilities (which include things like
having viewers for unusual MIME types, the quality factors of the MIME
types, and the quality factors of the accepted languages), because if
they would contain everything, you would basically get a different
profile file for each user (except maybe on the LANs of boring
companies), and the whole profile caching scheme breaks down horribly.

And if UA profiles can't cover all preferences and capabilities, then
you still need a second negotiation mechanism to handle the things not
in the profile.

So UA profiles won't solve all of our problems.  They could at best be
a short-term stopgap measure to reduce the pain before we have a
general mechanism.

But we already have a complete draft spec for a general mechanism,
transparent content negotiation, which will do much more than
negotiate on UA features alone.  The general mechanism could be
finished well before the stopgap!

I estimate that to go from here to a complete internet draft for
profile sharing would take months at least.  The addition of a third
party in the negotiation process generates so many
security/reliability/authentication/privacy problems that the fast
production of a simple draft seems out of the question.

>Dave Morris

Koen.
Received on Monday, 12 August 1996 16:00:46 EDT

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