W3C home > Mailing lists > Public > public-html@w3.org > October 2009

RE: Hyperlinks and content negotiation

From: Larry Masinter <masinter@adobe.com>
Date: Fri, 16 Oct 2009 12:24:07 -0700
To: Smylers <Smylers@stripey.com>, Mike Kelly <mike@mykanjo.co.uk>, "public-html@w3.org" <public-html@w3.org>
Message-ID: <8B62A039C620904E92F1233570534C9B0118DC469E35@nambx04.corp.adobe.com>
> HTML does not currently provision for hyperlinks to indicate a
> specific content-type preference for the Accept header of a given
> request.

In content negotiation in HTTP, the requestor (client, browser)
tells the server the preferences, capabilities or characteristics.
Putting a "content-type" 'preference' in the HTML doesn't make
much sense from this point of view: the producer of the HTML is
telling the consumer of the HTML what the consumer's preferences
should be?

> This feature would also break bookmarks: a user could bookmark a page's
> URL, believing that the URL identifies that page, yet on later visiting
> that bookmark being served different content.

The producer of a resource which returns different representations
for different requests takes the responsibility for insuring that,
from the producer's point of view, the representations are equivalent.

> Without a formal mechanism in HTML which can specify to UAs the
> contextual content-type preference for a given hyperlink, HTML is not
> a viable hypermedia format for systems which must rigorously leverage
> HTTP conneg 

What systems "must rigorously leverage HTTP connect" (and what
does that mean?)

BTW, the text around content negotiation in HTTP was recently
rewritten, see 


and the proposed rewrite (scheduled for inclusion in -08 spec):

with minor corrections:


Received on Friday, 16 October 2009 19:24:39 UTC

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