Conventions for Sharing User Agent Profiles

One way to reduce the number of accept headers, and user agent
description headers is to leverage the existing user agent field.
Right now its a pain for sites to build a database that associates
user agent values to feature sets. There is no agreed language for
describing these sets and no way of exchanging them.

What if we could define a simple file format for describing the
feature set for a given user agent, in analogy to the way robots.txt
emerged as a useful convention? This would allow sites to exchange
information easily. It would be an easy matter to create URLs for
access a database of such definitions. The information could be
shared when needed or in advance as appropriate.

When an HTTP request is seen for a previously unseen user agent,
the database could be consulted to determine the profile. The
first person to access the site with a new user agent takes a
hit but thereafter everyone wins. Note that this doesn't require
any changes to HTTP.

It may also be useful for vendors to say that their user agent
emulates, let's say Netscape Navigator 2.0. It would be a win if
the browser could send this as an additional HTTP header in the
request, e.g. "UA-Emulates:". This would reduce the size of the
UA profile database and reduce the hit taken by the first visitor
with the this ua.

Is anyone interested in taking these ideas further?

Dave Raggett

Received on Saturday, 10 August 1996 08:52:26 UTC