SIOC::Exporter - SIOC RDF exporter class

   use SIOC::Exporter;

   # create SIOC object instance, e.g. a SIOC::User
   use SIOC::User;
   my $user = SIOC::User->new(...);

   # create exporter instance
   my $exporter = SIOC::Exporter->new({
       host => 'http://www.example.com',
   });

   # pass object to exporter
   $exporter->export_object($user);

   # output the object's information as RDF data
   print $exporter->output(), "\n";

    * Redistributions of source code must retain the above copyright notice,
      this list of conditions and the following disclaimer.

    * Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in the
      documentation and/or other materials provided with the distribution.

    * The names of its contributors may not be used to endorse or promote
      products derived from this software without specific prior written
      permission.

###########################################################
# SIOC::Exporter
# Exporter class for the SIOC ontology
###########################################################
#
# $Id: Exporter.pm 21 2008-03-21 17:45:07Z geewiz $
#

package SIOC::Exporter;

use strict;
use warnings;

use version; our $VERSION = qv(1.0.0);

use Moose;
use MooseX::AttributeHelpers;
use Carp;

# singleton Template::Provider for this class
my $template_provider = Template::Provider::FromDATA->new({
    CLASSES => __PACKAGE__,
});

### required attributes

has 'host' => (
    isa => 'Str',
    is => 'rw',
    required => 1,
);

### optional attributes

has 'encoding' => (
    isa => 'Str',
    is => 'ro',
    default => sub { 'utf-8' },
);
has 'generator' => (
    isa => 'Str',
    is => 'ro',
    default => sub { 'perl-SIOC' },
);
has 'export_email' => (
    isa => 'Str',
    is => 'ro',
    default => sub { 0 },
);
    
### internal attributes

has '_object' => (
    isa => 'SIOC',
    is => 'rw',
);
has '_url' => (
    isa => 'Str',
    is => 'ro',
    default => sub { 'http://wiki.sioc.org/...' },
);
has '_version' => (
    isa => 'Str',
    is => 'ro',
    default => sub { "$VERSION" },    
);

### methods

sub _init_template {
    my ($self) = @_;

    # create new Template object
    my $template = Template->new({
        LOAD_TEMPLATES => [ 
            $template_provider,
        ]
    });

    return $template;
}

sub register_object {
    my ($self, $object) = @_;
    
    my $export_url = $self->object_export_url($object);
    $object->export_url($export_url);
    
    return $export_url;
}

sub export_object {
    my ($self, $object) = @_;
    
    $self->_object($object);
    
    return 1;
};

sub object_export_url {
    my ($self, $object) = @_;
    
    my $url = sprintf("%s/sioc.pl?class=%s&id=%s", 
        $self->host,
        $object->type, 
        $object->id
    );

    return $url;
}

sub output {
    my ($self) = @_;

    # prepare template engine
    my $template = $self->_init_template();
    my $output;

    my $object_rdf = q();

    # set object url attribute
    $self->_object->export_url($self->object_export_url($self->_object));

    # fill template variables
    my $template_vars = {
        encoding => $self->encoding,
        exporter_url => $self->_url,
        exporter_version => $VERSION,
        exporter_generator => 'perl-SIOC',
        object => $self->_object,
    };

    # process template
    my $ok = $template->process('rdfoutput', $template_vars, \$output);
    if (! $ok) {
        croak $template->error();
    }

    return $output;
}

1;
__DATA__
__rdfoutput__
Content-Type: application/rdf+xml; charset=[% encoding %]

<?xml version="1.0" encoding="[% encoding %]" ?>
<rdf:RDF
    xmlns="http://xmlns.com/foaf/0.1/"
    xmlns:foaf="http://xmlns.com/foaf/0.1/"
    xmlns:admin="http://webns.net/mvcb/"
    xmlns:content="http://purl.org/rss/1.0/modules/content/"
    xmlns:dc="http://purl.org/dc/elements/1.1/"
    xmlns:dcterms="http://purl.org/dc/terms/"
    xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"
    xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
    xmlns:sioc="http://rdfs.org/sioc/ns#">

<foaf:Document rdf:about="">
	<dc:title>SIOC profile for [% object.name %]</dc:title>
	<dc:description>A SIOC profile describes the structure and contents of a community site (e.g., weblog) in a machine processable form. For more information refer to the <a href="http://rdfs.org/sioc">SIOC project page</a>'></dc:description>
	<foaf:primaryTopic rdf:resource="[% object.url | url %]"/>
	<admin:generatorAgent rdf:resource="[% exporter_url | url %]?version=[% exporter_version | uri %]"/>
	<admin:generatorAgent rdf:resource="[% exporter_generator %]"/>
</foaf:Document>

[% IF rdf_content %][% rdf_content %][% END %]

[% IF object %]
<!-- type: [% object.type %], id: [% object.id %] -->
[% object.export_rdf %]
[% END %]

</rdf:RDF>
__END__