=head1 NAME
EPrints::Plugin::Search::SOLR_integration
=head1 PARAMETERS
=over 4
=item lang
Override the default language used for stemming.
=item stopwords
An array reference of stop words to use (defaults to English).
=back
=head1 METHODS
=over 4
=cut
package EPrints::Plugin::Search::SOLR_integration;

@ISA = qw( EPrints::Plugin::Search );
our $VERSION = '0.0.2';

use strict;
use warnings;

sub new
{
my( $class, %params ) = @_;
my $self = $class->SUPER::new( %params );
$self->{name} = "solr";
$self->{search} = [qw( simple/* )];
$self->{result_order} = 1; # whether to default to showing by engine result order
if ( !defined $self->{session} )
{
EPrints::abort( 'The Solr plugin requires that the \'session\' parameter be defined.\n' );
}
$self->url($self->{session}->get_repository->get_conf( 'solr_url' ) )
unless( defined $self->{solr_url} );
return $self;
}

sub url
{
my( $self, $url ) = @_;
$self->{solr_url} = $url if( defined $url );
return $self->{solr_url};
}

sub ping
{
my( $self ) = @_;
my $ping_url = $self->{solr_url}.'/admin/ping';
my $response = $self->_query_server( $ping_url );
my $ping_result = 0;
return 0 unless( defined $response );
foreach my $element ( $response->getChildNodes )
{
next unless( $element->nodeName eq 'str' );
foreach my $attribute ( $element->attributes )
{
next unless( $attribute->nodeName eq 'name' );
last unless( $attribute->nodeValue eq 'status' );
if( $element->textContent eq 'OK' )
{
$ping_result = 1;
}
last;
}
}
return $ping_result;
}

sub add_to_index
{
my( $self, $eprint ) = @_;
my $ds = $eprint->get_dataset;
my $xml = $self->{session}->xml;
my $add = $xml->create_element( 'add' );
my $doc = $xml->create_element( 'doc' );
my @solr_index_fields = @{$self->{session}->get_repository->get_conf( 'solr_index_fields' )};
foreach my $solr_index_field ( @solr_index_fields )
{
my $value = $eprint->get_value( $solr_index_field );
if( defined $value )
{
if( $ds->get_field( $solr_index_field )->get_property( 'multiple' ) )
{
foreach( @{$value} )
{
$doc->appendChild( $self->_create_solr_document_field( $solr_index_field, $_ ) );
}
}
else
{
$doc->appendChild( $self->_create_solr_document_field( $solr_index_field, $value ) );
}
}
}
$add->appendChild( $doc );
$self->_send_solr_operation( $add );
}

sub _create_solr_document_field
{
my( $self, $name, $value ) = @_;
my $xml = $self->{session}->xml;
my $solr_xml_field = $xml->create_element( 'field', name => $name );
$solr_xml_field->appendChild( $xml->create_text_node( $value ) );
return $solr_xml_field;
}

sub _send_solr_operation
{
my( $self, $op ) = @_;
my $doc = $self->{session}->xml->create_document_fragment;
$doc->appendChild( $op );
print STDERR EPrints::XML::to_string( $doc )."\n";
my $browser = new LWP::UserAgent;
$browser->agent( __PACKAGE__."/$VERSION" );
}

sub _query_server
{
my( $self, $url ) = @_;
my $browser = new LWP::UserAgent;
$browser->agent( __PACKAGE__."/$VERSION" );
my $server_response = $browser->get( $url );
print STDERR $server_response->code."\n";
return unless( $server_response->code eq 200 );
my $xml = $self->{session}->xml;
my $doc = $xml->parse_string( $server_response->content );
my $response = ($doc->getElementsByTagName( 'response' ))[0];
unless( defined ( $response ) )
{
print STDERR 'The Solr plugin did not recieve a valid response from the server. Is Solr running at '.$self->{solr_url}.'?';
EPrints::XML::dispose( $doc );
}
return $response;
}

package EPrints::DataObj::EPrint;

no warnings;

sub commit
{
my( $self, $force ) = @_;
my $success = $self->SUPER::commit( $force );
if( $success )
{
my $solr = new EPrints::Plugin::Solr( session => $self->{session} );
$solr->add_to_index( $self );
}
return $success;
}
1;
=back
=head1 COPYRIGHT
=for COPYRIGHT BEGIN
Copyright 2000-2013 University of Southampton.
=for COPYRIGHT END
=for LICENSE BEGIN
This file is part of EPrints L<http://www.eprints.org/>.
EPrints is free software: you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published
by the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
EPrints is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
License for more details.
You should have received a copy of the GNU Lesser General Public
License along with EPrints. If not, see L<http://www.gnu.org/licenses/>.
=for LICENSE END