---
name: "XML::GRDDL"
section: "3pm"
platform: "linux"
package: "libxml-grddl-perl"
version: "0.004-5"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/XML::GRDDL"
---

# XML::GRDDL(3pm)

transform XML and XHTML to RDF

## 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.