xfolk-to-rdf-old - Revision history

TobyInk: /* The Predicates */ Correct DC 1.1 URIs

2008-05-02T22:02:13Z

The Predicates: Correct DC 1.1 URIs

← Older revision		Revision as of 22:02, 2 May 2008
Line 21:		Line 21:
	The following predicates are used:		The following predicates are used:

	* http://purl.org/dc/terms/title or http://purl.org/dc/1.1/title		* http://purl.org/dc/terms/title or http://purl.org/dc/elements/1.1/title
	* http://purl.org/dc/terms/source or http://purl.org/dc/1.1/source		* http://purl.org/dc/terms/source or http://purl.org/dc/elements/1.1/source
	* http://purl.org/dc/terms/abstract		* http://purl.org/dc/terms/abstract

TobyInk: Fix ups

2008-05-02T20:17:20Z

Fix ups

← Older revision		Revision as of 20:17, 2 May 2008
Line 1:		Line 1:
	<h1>xFolk → RDF</h1>		<h1>xFolk → RDF</h1>
			{{TOC-right}}
	<p style="margin-bottom:2.5em">by Toby Inkster</p>		<p style="margin-bottom:2.5em">by Toby Inkster</p>

Line 38:		Line 39:
	The following example xFolk entry is included in the [[xfolk\|xFolk specification]] (ID attribute added for the purposes of illustration):		The following example xFolk entry is included in the [[xfolk\|xFolk specification]] (ID attribute added for the purposes of illustration):

	<nowiki>		<pre><nowiki>
	<div class="xfolkentry" id="rtags">		<div class="xfolkentry" id="rtags">
	<div>		<div>
Line 61:		Line 62:
	</div>		</div>
	</div>		</div>
	</nowiki>		</nowiki></pre>

	The above could generate the following RDF/XML:		The above could generate the following RDF/XML:

	<nowiki>		<pre><nowiki>
	<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"		<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
	xmlns:dc="http://purl.org/dc/terms/">		xmlns:dc="http://purl.org/dc/terms/">
Line 79:		Line 80:
	</rdf:Description>		</rdf:Description>
	</rdf:RDF>		</rdf:RDF>
	</nowiki>		</nowiki></pre>

	== Extending xFolk with RDFa ==		== Extending xFolk with RDFa ==
Line 85:		Line 86:
	Because the xFolk entry and the link each have a URI, they can be used as subjects in [http://www.w3.org/2006/07/SWD/RDFa/syntax/ RDFa]:		Because the xFolk entry and the link each have a URI, they can be used as subjects in [http://www.w3.org/2006/07/SWD/RDFa/syntax/ RDFa]:

	<nowiki>		<pre><nowiki>
	<dl>		<dl>
	<dt>Page by</dt>		<dt>Page by</dt>
Line 98:		Line 99:
	<dd about="#rtags" property="dc:date">2005-04-11</dd>		<dd about="#rtags" property="dc:date">2005-04-11</dd>
	</dl>		</dl>
	</nowiki>		</nowiki></pre>

	Added to the earlier HTML example, this ends up as:		Added to the earlier HTML example, this ends up as:

	<nowiki>		<pre><nowiki>
	<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"		<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
	xmlns:dc="http://purl.org/dc/terms/">		xmlns:dc="http://purl.org/dc/terms/">
Line 123:		Line 124:
	</rdf:Description>		</rdf:Description>
	</rdf:RDF>		</rdf:RDF>
	</nowiki>		</nowiki></pre>

	== Extending xFolk with eRDF ==		== Extending xFolk with eRDF ==

	[http://research.talis.com/2005/erdf/wiki/Main/RdfInHtml eRDF] can be used instead of RDFa, however due to limitations of eRDF syntax, it can only be used to specify additional metadata about the xFolk entry, and not the tagged link.		[http://research.talis.com/2005/erdf/wiki/Main/RdfInHtml eRDF] can be used instead of RDFa, however due to limitations of eRDF syntax, it can only be used to specify additional metadata about the xFolk entry, and not the tagged link.

			== Related Pages ==

			=== xFolk ===

			{{template:xfolk-related-pages}}

			=== Microformats to RDF ===

			{{uf-rdf-related-pages}}

TobyInk: New page on xFolk to RDF

2008-05-02T20:12:40Z

New page on xFolk to RDF

New page

<h1>xFolk → RDF</h1>
<p style="margin-bottom:2.5em">by Toby Inkster</p>

This article describes a method for converting an [[xfolk|xFolk]] object into RDF triples and suggests ways of using RDFa or eRDF to extend xFolk, adding additional information about the xFolk object, and about the article that has been linked to.

[http://digg.com/ Digg] is an example of the type of site that could make use of xFolk, but in April 2008 they instead implemented support for RDFa. Their choice of RDF for representing tagged links is used as the basis for this article.

== The Triples ==

=== The Subject ===

RDF represents all information in the form of "triples". The first part of a triple is the subject - a URI for the thing being described. Although at first the obvious choice for the subject might be the URI of the tagged link (and this is how I initially implemented xFolk→RDF), Digg instead uses its own page as the subject. So for our triple, the subject will be the URI of the xFolk object itself. The URI can be determined like this:

# If the tag with <code>class="xfolkentry"</code> is a <code><body></code> element, then the subject URI is the URI of the page being parsed.
# Otherwise, if the tag with <code>class="xfolkentry"</code> has an <code>id</code> attribute, then the subject URI is the page URI followed by a hash symbol (#) followed by the contents of the <code>id</code> attribute.
# Lastly, if none of the above applies, then there is no subject URI, so a [http://en.wikipedia.org/wiki/Blank_node BNode] is created.

=== The Predicates ===

The following predicates are used:

* http://purl.org/dc/terms/title or http://purl.org/dc/1.1/title
* http://purl.org/dc/terms/source or http://purl.org/dc/1.1/source
* http://purl.org/dc/terms/abstract

(Editor's note: I've not 100% decided the best way of representing tags. Will get there soon though.)

=== The Objects ===

The object of <code>dcterms:source</code> is a resource with the URI found in the <code>href</code> attribute of the element with <code>class="taggedlink"</code>.

The object of <code>dcterms:title</code> is a string literal consisting of the contents of the element with <code>class="taggedlink"</code>.

The object of <code>dcterms:abstract</code> is a string literal consisting of the contents of the element with <code>class="description"</code>.

=== An Example ===

The following example xFolk entry is included in the [[xfolk|xFolk specification]] (ID attribute added for the purposes of illustration):

<nowiki>
<div class="xfolkentry" id="rtags">
<div>
<a class="taggedlink" href="http://www.sifry.com/alerts/archives/000306.html">
Sifry's Alerts: Technorati launches Related Tags
</a>
</div>
<div class="description">
Ever wanted to see what posts are related to other posts, what tags
are related to others? Now you can! Just check under the Tag
description on most tag pages, like this one, or this one, and you'll
see the patterns. Can you smell the emergence?
</div>
<div class="meta">
to
<a rel="tag" href="/fpgibson/folksonomy">folksonomy</a>
<a rel="tag" href="/fpgibson/technorati">technorati</a>
... <a class="delNav" href="/url/cbcabf7de070fdb46598ee679367be49">
and 1 other person
</a>
... on 2005-04-09
</div>
</div>
</nowiki>

The above could generate the following RDF/XML:

<nowiki>
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:dc="http://purl.org/dc/terms/">
<rdf:Description rdf:about="http://example.org/#rtags">
<dc:source rdf:resource="http://www.sifry.com/alerts/archives/000306.html" />
<dc:title>Sifry's Alerts: Technorati launches Related Tags</dc:title>
<dc:abstract>
Ever wanted to see what posts are related to other posts, what tags
are related to others? Now you can! Just check under the Tag
description on most tag pages, like this one, or this one, and you'll
see the patterns. Can you smell the emergence?
</dc:abstract>
</rdf:Description>
</rdf:RDF>
</nowiki>

== Extending xFolk with RDFa ==

Because the xFolk entry and the link each have a URI, they can be used as subjects in [http://www.w3.org/2006/07/SWD/RDFa/syntax/ RDFa]:

<nowiki>
<dl>
<dt>Page by</dt>
<dd about="http://www.sifry.com/alerts/archives/000306.html"
property="dc:creator">Sifry</dd>
<dt>Page published on</dt>
<dd about="http://www.sifry.com/alerts/archives/000306.html"
property="dc:date">2005-04-09</dd>
<dt>Link submitted by</dt>
<dd about="#rtags" property="dc:creator">Alice Jones</dd>
<dt>Link submitted on</dt>
<dd about="#rtags" property="dc:date">2005-04-11</dd>
</dl>
</nowiki>

Added to the earlier HTML example, this ends up as:

<nowiki>
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:dc="http://purl.org/dc/terms/">
<rdf:Description rdf:about="http://example.org/#rtags">
<dc:source>
<rdf:Description rdf:about="http://www.sifry.com/alerts/archives/000306.html">
<dc:creator>Sifry</dc:creator>
<dc:date>2005-04-09</dc:date>
</rdf:Description>
</dc:source>
<dc:title>Sifry's Alerts: Technorati launches Related Tags</dc:title>
<dc:abstract>
Ever wanted to see what posts are related to other posts, what tags
are related to others? Now you can! Just check under the Tag
description on most tag pages, like this one, or this one, and you'll
see the patterns. Can you smell the emergence?
</dc:abstract>
<dc:creator>Alice Jones</dc:creator>
<dc:date>2005-04-11</dc:date>
</rdf:Description>
</rdf:RDF>
</nowiki>

== Extending xFolk with eRDF ==

[http://research.talis.com/2005/erdf/wiki/Main/RdfInHtml eRDF] can be used instead of RDFa, however due to limitations of eRDF syntax, it can only be used to specify additional metadata about the xFolk entry, and not the tagged link.