File Coverage

blib/lib/WQS/SPARQL.pm

Criterion	Covered	Total	%
statement	44	60	73.3
branch	3	10	30.0
condition			n/a
subroutine	11	14	78.5
pod	3	3	100.0
total	61	87	70.1

package WQS::SPARQL;

use strict;
use warnings;

use Class::Utils qw(set_params);
use Error::Pure qw(err);
use HTTP::Request;
use JSON::XS;
use LWP::UserAgent;
use URI;
use URI::QueryParam;
use Unicode::UTF8 qw(encode_utf8);

our $VERSION = 0.02;

# Constructor.
sub new {
	my ($class, @params) = @_;

	# Create object.
	my $self = bless {}, $class;

	# User agent.
	$self->{'agent'} = __PACKAGE__." ($VERSION)";

	# LWP::UserAgent object.
	$self->{'lwp_user_agent'} = undef;

	# Query site.
	$self->{'query_site'} = 'query.wikidata.org';

	# SPARQL endpoint.
	$self->{'sparql_endpoint'} = '/bigdata/namespace/wdq/sparql';

	# Verbose mode.
	$self->{'verbose'} = 0;

	# Process parameters.
	set_params($self, @params);

	if (! defined $self->{'lwp_user_agent'}) {
		$self->{'lwp_user_agent'} = LWP::UserAgent->new(
			'agent' => $self->{'agent'},
		);
	} else {
		if (! $self->{'lwp_user_agent'}->isa('LWP::UserAgent')) {
			err "Parameter 'lwp_user_agent' must be a 'LWP::UserAgent' instance.";
		}
	}

	# Full URL of api.
	$self->{'_api_uri'} = 'https://'.$self->{'query_site'}.$self->{'sparql_endpoint'};

	return $self;
}

sub query {
	my ($self, $query) = @_;

	if ($self->{'verbose'}) {
		print encode_utf8($query)."\n";
	}

	my $uri = URI->new($self->{'_api_uri'});
	$uri->query_param_append('format' => 'json');
	$uri->query_param_append('query' => $query);

	return $self->_http_get_json($uri->as_string);
}

sub query_count {
	my ($self, $query) = @_;

	my $ret_hr = $self->query($query);

	return $ret_hr->{'results'}->{'bindings'}->[0]->{'count'}->{'value'};
}

sub _http_get_json {
	my ($self, $uri) = @_;

	my $res = $self->{'lwp_user_agent'}->get($uri);
	if ($res->is_success) {
		my $content = decode_json($res->decoded_content);
		return wantarray ? ($content, $res->headers) : $content;
	} else {
		err 'Cannot get.',
			'Error', $res->status_line,
			'URI', $uri;
	}
}

1;

__END__