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

From: Bjoern Hoehrmann <derhoermi@gmx.net>
Date: Mon, 04 Nov 2013 18:50:18 +0100
To: ht@inf.ed.ac.uk (Henry S. Thompson)
Cc: ietf-http-wg@w3.org, www-tag@w3.org
Message-ID: <80mf79l5ea39otv4nr6qgmr9s6an55am7t@hive.bjoern.hoehrmann.de>
* Henry S. Thompson wrote:
>In particular, the discussion of the relative disadvantages of the
>newly (re-)named 'proactive' and 'reactive' variants are not only
>out-of-date, but also this discussion appears to at least this reader
>to amount to a recommendation for 'reactive' negotiation.  Yet as far
>as I can tell no user agents _or_ servers actually support this
>approach today, as it's described here.

It does not seem far off, it just so happens that for sub-resources a
substantial part of the process often happens on a level above HTTP.
As noted in the draft, it can be costly to contact the server first,
and then contact it again to request some alternative representation,
compared to encoding "we serve WOFF and SVG fonts, take your pick" in
HTML or CSS code. It might be good to note that shift in the document,
but I do not agree that keeping the text as is would be a "serious
mistake".

>I was sufficiently concerned about this question to undertake a
>moderately extensive empirical investigation [2].  To summarise
>perhaps too briefly, I found _no_ evidence of the use of reactive
>conneg in over 75 million HTTP request/response exchanges.

So with `<a href='example.txt' rel='alternate'>Download plain text
version of this document</a>`, if the user downloads the plain text
version, would that be evidence? If not, is the problem that the
user agent did not generate a redundant selection menu, or perhaps
because people do not include the `rel='alternate'` attribute since
user agents tend to ignore that? Or because this doesn't use HTTP
headers (what if it was <link> elements instead)?
-- 
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 Monday, 4 November 2013 17:50:48 UTC

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