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Re: Uniform access to descriptions

From: Harry Halpin <hhalpin@ibiblio.org>
Date: Thu, 20 Mar 2008 15:44:38 -0400
Message-ID: <47E2BEA6.70503@ibiblio.org>
To: "Roy T. Fielding" <fielding@gbiv.com>
Cc: Pat Hayes <phayes@ihmc.us>, "www-tag@w3.org WG" <www-tag@w3.org>

Roy T. Fielding wrote:
> It is my experience that whenever anyone here says just about anything
> negative about configuring a web server, the only thing they have really
> lacked is the fortitude to read the documentation on how to do it.
> They are just repeating the same old wives tales, over and over again.

I agree in general Roy on most Web hosting companies that are worth
their salt should and do allow this, but the problem we have had (with
GRDDL and other technologies) is that often the people who want to
deploy them do not have that level of access (they use something like
http://www.blogspot.com or an automatic generator[1] that lets them cut
and paste into arbitrary HTML). They are used to hosting their services
on these new-fangled Web services that do not give the user of the
service access to any htaccess file or web-apps. I think this is a
*problem* with these web services, but the fact of the matter is people
use them. This has been one of the main objections to the use of "link"
and "profile" in HTML 5 and the use of GRDDL in the microformat community.

I am a bit surprised everyone missed the point of my previous e-mail,
which is to allow whatever solution exists to be done on three distinct
levels (maybe four given above problem): the level of the HTTP header,
the level of RDF, and the level of HTML, both in the header and in the
body. All these techniques should be equivalent, i.e. any RDF/RDFa
parser should sniff all three. This is a RDF problem mostly I think, but
could be useful in other contexts as well, although implementation
details are a bit trickier outside RDF world (in RDF world, we should
just have these triples retrieved).

So, here's the three levels:

1) As a typed link header, as in "Link:

This should be equivalent to some RDF.

2) As a normal RDF statement, as "http://www.example.com/resource
http://www.w3c.org/example/describedBy http://www.example.org/mydescription

This RDF should be able to be embedded in any HTML page, in case user
does not know about HTTP headers or RDF.

3) In HTML Header (and arbitrary XML):
<LINK rel="http://www.w3c.org/example/describedBy"

4) In HTML body RDFa style (this may not be the best choice, could use
span, etc.)
<div rel="ex:describedBy" class="ex2:mydescription"
xmlns:ex="http://..." xmlns:ex2="http://...">
Blah blah

The important thing is that these methods be equivalent. Otherwise we
are privileging HTTP headers, when it's obvious when people want to
attach descriptions in a normative manner they may want to do it other
ways besides using HTTP headers.

[1] http://microformats.org/code/hcard/creator
> ....Roy


Harry Halpin,  University of Edinburgh 
http://www.ibiblio.org/hhalpin 6B522426
Received on Thursday, 20 March 2008 19:45:17 UTC

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