NAME

       XML::GRDDL - transform XML and XHTML to RDF

SYNOPSIS

       High-level interface:

        my $grddl = XML::GRDDL->new;
        my $model = $grddl->data($xmldoc, $baseuri);
        # $model is an RDF::Trine::Model

       Low-level interface:

        my $grddl = XML::GRDDL->new;
        my @transformations = $grddl->discover($xmldoc, $baseuri);
        foreach my $t (@transformations)
        {
          # $t is an XML::GRDDL::Transformation
          my ($output, $mediatype) = $t->transform($xmldoc);
          # $output is a string of type $mediatype.
        }

DESCRIPTION

       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
       "XML::GRDDL->new"
           The constructor accepts no parameters and returns an XML::GRDDL object.

   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.

   Constants
       These constants may be exported upon request.

       "GRDDL_NS"
       "XHTML_NS"

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, XML::Saxon::XSLT2.

       HTML::HTML5::Parser, RDF::RDFa::Parser, HTML::Microformats.

       JSON::GRDDL.

       <http://www.w3.org/TR/grddl/>.

       <http://www.perlrdf.org/>.

       This module is derived from Swignition <http://buzzword.org.uk/swignition/>.

AUTHOR

       Toby Inkster <tobyink@cpan.org>.

COPYRIGHT AND LICENCE

       Copyright 2008-2012 Toby Inkster

       This library is free software; you can redistribute it and/or modify it under the same
       terms as Perl 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.