SYNOPSIS

use HTML::Embedded::Turtle;

my $het = HTML::Embedded::Turtle->new($html, $base_uri);
foreach my $graph ($het->endorsements)
{
my $model = $het->graph($graph);

# $model is an RDF::Trine::Model. Do something with it.
}

DESCRIPTION

RDF can be embedded in (X)HTML using simple <script> tags. This is described at <http://esw.w3.org/N3inHTML>. This gives you a file format that can contain multiple (optionally named) graphs. The document as a whole can ``endorse'' a graph by including:

 <link rel="meta" href="#foo" />

Where ``#foo'' is a fragment identifier pointing to a graph.

 <script type="text/turtle" id="foo"> ... </script>

The rel=``meta'' stuff is parsed using an RDFa parser, so equivalent RDFa works too.

This module parses HTML files containing graphs like these, and allows you to access them each individually; as a union of all graphs on the page; or as a union of just the endorsed graphs.

Despite the module name, this module supports a variety of <script type>s: text/turtle, application/turtle, application/x-turtle text/plain (N-Triples), text/n3 (Notation 3), application/x-rdf+json (RDF/JSON), application/json (RDF/JSON), and application/rdf+xml (RDF/XML).

The deprecated attribute ``language'' is also supported:

 <script language="Turtle" id="foo"> ... </script>

Languages supported are (case insensitive): ``Turtle'', ``NTriples'', ``RDFJSON'', ``RDFXML'' and ``Notation3''.

Constructor

"HTML::Embedded::Turtle->new($markup, $base_uri, \%opts)"

Create a new object. $markup is the HTML or XHTML markup to parse; $base_uri is the base URI to use for relative references.

Options include:

• markup

  Choose which parser to use: 'html' or 'xml'. The former chooses HTML::HTML5::Parser, which can handle tag soup; the latter chooses XML::LibXML, which cannot. Defaults to 'html'.

• rdfa_options

  A set of options to be parsed to RDF::RDFa::Parser when looking for endorsements. See RDF::RDFa::Parser::Config. The default is probably sensible.

Public Methods

"union_graph"

A union graph of all graphs found in the document, as an RDF::Trine::Model. Note that the returned model contains quads.

"endorsed_union_graph"

A union graph of only the endorsed graphs, as an RDF::Trine::Model. Note that the returned model contains quads.

"graph($name)"

A single graph from the page.

"graphs"

"all_graphs"

A hashref where the keys are graph names and the values are RDF::Trine::Models. Some graph names will be URIs, and others may be blank nodes (e.g. ``_:foobar'').

"graphs" and "all_graphs" are aliases for each other.

"endorsed_graphs"

Like "all_graphs", but only returns endorsed graphs. Note that all endorsed graphs will have graph names that are URIs.

"endorsements"

Returns a list of URIs which are the names of endorsed graphs. Note that the presence of a URI $x in this list does not imply that "$het->graph($x)" will be defined.

"dom"

Returns the page DOM.

"uri"

Returns the page URI.

AUTHOR

Toby Inkster <[email protected]>.

COPYRIGHT AND LICENSE

Copyright (C) 2010-2011, 2013 by Toby Inkster.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.

DISCLAIMER OF WARRANTIES

THIS PACKAGE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.