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Re: Feedback for draft-nottingham-http-link-header-03

From: Mark Nottingham <mnot@mnot.net>
Date: Wed, 10 Dec 2008 20:51:07 +1100
Cc: "Roy T. Fielding" <fielding@gbiv.com>, HTTP Working Group <ietf-http-wg@w3.org>
Message-Id: <55403FDE-189B-49AB-8DDE-17CD3418BC52@mnot.net>
To: Julian Reschke <julian.reschke@gmx.de>

I though I had it, but I don't; Roy's explanation made sense, but his  
interpretation of HTML2 links -- AIUI -- contradicts the example in  
HTML2's REV definition.

Roy?


On 10/12/2008, at 8:28 PM, Julian Reschke wrote:

>
> Mark Nottingham wrote:
>> ...
>>      <t>HTML4 also has a "rev" parameter for links that allows a  
>> link's relation to be reversed. The Link header
>>        has a "rev" parameter to allow the expression of these links  
>> in HTTP headers, but its use is not encouraged,
>>        due to the confusion this mechanism causes as well as  
>> conflicting interpretations among HTML versions.</t>
>> ...
>
> OK, it seems I'm missing something here. Could somebody explain to  
> me, what the conflicting interpretations are, and which we prefer  
> (and why?)?
>
> HTML2 (<http://tools.ietf.org/html/rfc1866#section-5.7.3>):
>
>    REL
>            The REL attribute gives the relationship(s) described by
>            the hyperlink. The value is a whitespace separated list
>            of relationship names. The semantics of link
>            relationships are not specified in this document.
>
>    REV
>            same as the REL attribute, but the semantics of the
>            relationship are in the reverse direction. A link from A
>            to B with REL="X" expresses the same relationship as a
>            link from B to A with REV="X". An anchor may have both
>            REL and REV attributes.
>
> HTML4 (<http://www.w3.org/TR/html4/struct/links.html#rev-link>):
>
>  12.3.1 Forward and reverse links
>
>  The rel and rev attributes play complementary roles -- the rel
>  attribute specifies a forward link and the rev attribute specifies a
>  reverse link.
>
>  Consider two documents A and B.
>
>    Document A:       <LINK href="docB" rel="foo">
>
>  Has exactly the same meaning as:
>
>    Document B:       <LINK href="docA" rev="foo">
>
>  Both attributes may be specified simultaneously.
>
>
>
> Best regards, Julian
>


--
Mark Nottingham     http://www.mnot.net/
Received on Wednesday, 10 December 2008 09:51:47 GMT

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