NAME
XML::GRDDL - transform XML and XHTML to RDF
SYNOPSIS
# Low-Level Interface
#
my $grddl = XML::GRDDL->new;
my @transformations = $grddl->discover($xmldoc, $baseuri);
foreach my $trans (@transformations)
{
# $t is an XML::GRDDL::Transformation
my ($output, $mediatype) = $t->transform($xmldoc);
}
# High-Level Interface
#
my $grddl = XML::GRDDL->new;
my $model = $grddl->data($xmldoc, $baseuri);
# $model is an RDF::Trine::ModelDESCRIPTION
GRDDL is a W3C Recommendation for extracting RDF data from arbitrary XML and XHTML via a transformation, typically written in XSLT. See http://www.w3.org/TR/grddl/ for more details.
This module implements GRDDL in Perl. It offers both a low level interface, allowing you to generate a list of transformations associated with the document being processed, and thus the ability to selectively run the transformation; and a high-level interface where a single RDF model is returned representing the union of the RDF graphs generated by applying all available transformations.
Constructor
Methods
$grddl->discover($xml, $base, %options)-
Processes the document to discover the transformations associated with it. $xml is the raw XML source of the document, or an XML::LibXML::Document object. ($xml cannot be "tag soup" HTML, though you should be able to use HTML::HTML5::Parser to parse tag soup into an XML::LibXML::Document.) $base is the base URI for resolving relative references.
Returns a list of XML::GRDDL::Transformation objects.
Options include:
force_rel - boolean; interpret XHTML rel="transformation" even in the absence of the GRDDL profile.
strings - boolean; return a list of plain strings instead of blessed objects.
$grddl->data($xml, $base, %options)-
Processes the document, discovers the transformations associated with it, applies the transformations and merges the results into a single RDF model. $xml and $base are as per
discover.Returns an RDF::Trine::Model containing the data. Statement contexts (a.k.a. named graphs / quads) are used to distinguish between data from the result of each transformation.
Options include:
force_rel - boolean; interpret XHTML rel="transformation" even in the absence of the GRDDL profile.
metadata - boolean; include provenance information in the default graph (a.k.a. nil context).
$grddl->ua( [$ua] )-
Get/set the user agent used for HTTP requests. $ua, if supplied, must be an LWP::UserAgent.
FEATURES
XML::GRDDL supports transformations written in XSLT 1.0, and in RDF-EASE.
XML::GRDDL is a good HTTP citizen: Referer headers are included in requests, and appropriate Accept headers supplied. To be an even better citizen, I recommend changing the User-Agent header to advertise the name of the application:
$grddl->ua->default_header(user_agent => 'MyApp/1.0 ');Provenance information for GRDDL transformations is returned using the GRDDL vocabulary at http://www.w3.org/2003/g/data-view#.
Certain XHTML profiles and XML namespaces known not to contain any transformations, or to contain useless transformations are skipped. See XML::GRDDL::Namespace and XML::GRDDL::Profile for details. In particular profiles for RDFa and many Microformats are skipped, as RDF::RDFa::Parser and HTML::Microformats will typically yield far superior results.
BUGS
Please report any bugs to http://rt.cpan.org/.
Known limitations:
Recursive GRDDL doesn't work yet.
That is, the profile documents and namespace documents linked to from your primary document cannot themselves rely on GRDDL.
SEE ALSO
XML::GRDDL::Transformation, XML::GRDDL::Namespace, XML::GRDDL::Profile, XML::GRDDL::Transformation::RDF_EASE::Functional.
HTML::HTML5::Parser, RDF::RDFa::Parser, HTML::Microformats.
This module is derived from Swignition http://buzzword.org.uk/swignition/.
AUTHOR
Toby Inkster <tobyink@cpan.org>.
COPYRIGHT
Copyright 2008-2010 Toby Inkster
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.