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Re: Request that the WG reconsider section 3.4: Content Negotiation

From: Bjoern Hoehrmann <derhoermi@gmx.net>
Date: Tue, 05 Nov 2013 13:50:55 +0100
To: ht@inf.ed.ac.uk (Henry S. Thompson)
Cc: ietf-http-wg@w3.org, www-tag@w3.org
Message-ID: <rkoh791tb010okbdbbm549kbk5111pv7oo@hive.bjoern.hoehrmann.de>
* Henry S. Thompson wrote:
>What does rel='alternate' have to do with conneg, or HTTP?  Its
>semantics are defined, as you say above, at an entirely different

"Reactive negotiation" is performed "after receiving an initial response
from the origin server that contains a list of resources for alternative
representations." and in HTML `rel='alternate'` is a way to encode such
information that allows selecting an alternate representation "manually
by the user". The text in question describes using HTTP header fields to
carry this information as an "if" and for status codes like 300 and 406
the draft specifically says that the payload should include such a list.

There is nothing wrong with discussing in the specification that as an
alternative to the "you say what you like and then the server chooses"
it is also possible to implement "the server says what it has and then
you choose" and including hyperlinks in the response body is a widely
used way of doing so and it is implemented e.g. by search engines like
Google, <https://support.google.com/webmasters/answer/189077>. When my
server responds with, using the example there,

  HTTP/1.1 200 OK
  Link: <http://es.example.com/>; rel="alternate"; hreflang="es"

and a search engine crawler solely interested in spanish content then
automatically chooses to follow the link and to ignore the non-spanish
site, how is that not "Reactive negotiation" as described in the draft?
Björn Höhrmann · mailto:bjoern@hoehrmann.de · http://bjoern.hoehrmann.de
Am Badedeich 7 · Telefon: +49(0)160/4415681 · http://www.bjoernsworld.de
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Received on Tuesday, 5 November 2013 12:51:34 UTC

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