This file is indexed.

/usr/share/perl5/RDF/Endpoint.pm is in librdf-endpoint-perl 0.05-1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
=head1 NAME

RDF::Endpoint - A SPARQL Protocol Endpoint implementation

=head1 VERSION

This document describes RDF::Endpoint version 0.05.

=head1 SYNOPSIS

 plackup /usr/local/bin/endpoint.psgi

=head1 DESCRIPTION

This modules implements the SPARQL Protocol for RDF using the PSGI
interface provided by L<Plack>. It may be run with any Plack handler.
See L<Plack::Handler> for more details.

When this module is used to create a SPARQL endpoint, configuration variables
are loaded using L<Config::JFDI>. An example configuration file rdf_endpoint.json
is included with this package. Valid top-level configuration keys include:

=over 4

=item store

This is used to define the underlying L<RDF::Trine::Store> for the
endpoint.  It can be a hashref of the type that can be passed to
L<RDF::Trine::Store>->new_with_config, but a simple string can also be
used.

=item endpoint

A hash of endpoint-specific configuration variables. Valid keys for this hash
include:

=over 8

=item update

A boolean value indicating whether Update operations should be allowed to be
executed by the endpoint.

=item load_data

A boolean value indicating whether the endpoint should use URLs that appear in
FROM and FROM NAMED clauses to construct a SPARQL dataset by dereferencing the
URLs and loading the retrieved RDF content.

=item service_description

An associative array (hash) containing details on which and how much information
to include in the service description provided by the endpoint if no query is
included for execution. The boolean values 'default' and 'named_graphs' indicate
that the respective SPARQL dataset graphs should be described by the service
description.

=item html

An associative array (hash) containing details on how results should be
serialized when the output media type is HTML. The boolean value 'resource_links'
specifies whether URI values should be serialized as HTML anchors (links).
The boolean value 'embed_images' specifies whether URI values that are typed as
foaf:Image should be serialized as HTML images. If 'embed_images' is true, the
integer value 'image_width' specifies the image width to be used in the HTML
markup (letting the image height scale appropriately).

=back

=back

=head1 EXAMPLE CONFIGURATIONS

=head2 Using L<Plack::Handler::Apache2>

Using L<Plack::Handler::Apache2>, mod_perl2 can be configured to serve and
endpoint using the following configuration:

  <Location /sparql>
    SetHandler perl-script
    PerlResponseHandler Plack::Handler::Apache2
    PerlSetVar psgi_app /path/to/endpoint.psgi
    PerlSetEnv RDF_ENDPOINT_CONFIG /path/to/rdf_endpoint.json
  </Location>

To get syntax highlighting and other pretty features, in the
VirtualHost section of your server, add three aliases:

  Alias /js/ /path/to/share/www/js/
  Alias /favicon.ico /path/to/share/www/favicon.ico
  Alias /css/ /path/to/share/www/css/

The exact location can be determined by finding where the file C<sparql_form.js>.

=head1 METHODS

=over 4

=cut

package RDF::Endpoint;

use 5.008;
use strict;
use warnings;
our $VERSION	= '0.05';

use RDF::Query 2.905;
use RDF::Trine 0.134 qw(statement iri blank literal);

use Encode;
use File::Spec;
use Data::Dumper;
use Digest::MD5 qw(md5_hex);
use XML::LibXML 1.70;
use Plack::Request;
use Plack::Response;
use Scalar::Util qw(blessed refaddr);
use File::ShareDir qw(dist_dir);
use HTTP::Negotiate qw(choose);
use RDF::Trine::Namespace qw(rdf xsd);
use RDF::RDFa::Generator 0.102;
use IO::Compress::Gzip qw(gzip);
use HTML::HTML5::Parser;
use HTML::HTML5::Writer qw(DOCTYPE_XHTML_RDFA);
use Hash::Merge::Simple qw/ merge /;
use Fcntl qw(:flock SEEK_END);
use Carp qw(croak);


my $NAMESPACES	= {
	xsd			=> 'http://www.w3.org/2001/XMLSchema#',
	'format'	=> 'http://www.w3.org/ns/formats/',
	void		=> 'http://rdfs.org/ns/void#',
	scovo		=> 'http://purl.org/NET/scovo#',
	sd			=> 'http://www.w3.org/ns/sparql-service-description#',
	jena		=> 'java:com.hp.hpl.jena.query.function.library.',
	arq			=> 'http://jena.hpl.hp.com/ARQ/function#',
	ldodds		=> 'java:com.ldodds.sparql.',
	fn			=> 'http://www.w3.org/2005/xpath-functions#',
	sparql		=> 'http://www.w3.org/ns/sparql#',
};

=item C<< new ( \%conf ) >>

=item C<< new ( $model, \%conf ) >>

Returns a new Endpoint object. C<< \%conf >> should be a HASH reference with
configuration settings.

=cut

sub new {
	my $class	= shift;
	my $arg		= shift;
	my ($model, $config);
	if (blessed($arg) and $arg->isa('RDF::Trine::Model')) {
		$model	= $arg;
		$config	= shift;
		delete $config->{store};
	} else {
		$config		= $arg;
		my $store	= RDF::Trine::Store->new( $config->{store} );
		$model		= RDF::Trine::Model->new( $store );
	}
	
	unless ($config->{endpoint}) {
		$config->{endpoint}	= { %$config };
	}
	my $self	= bless( {
		conf		=> $config,
		model		=> $model,
		start_time	=> time,
	}, $class );
	$self->service_description();	# pre-generate the service description
	return $self;
}

=item C<< run ( $req ) >>

Handles the request specified by the supplied Plack::Request object, returning
an appropriate Plack::Response object.

=cut

sub run {
	my $self	= shift;
	my $req		= shift;
	
	my $config	= $self->{conf};
	my $endpoint_path = $config->{endpoint}{endpoint_path} || '/sparql';
	$config->{resource_links}	= 1 unless (exists $config->{resource_links});
	my $model	= $self->{model};
	
	my $content;
	my $response	= Plack::Response->new;
	unless ($req->path eq $endpoint_path) {
		my $path	= $req->path_info;
		$path		=~ s#^/##;
		my $dir		= $ENV{RDF_ENDPOINT_SHAREDIR} || eval { dist_dir('RDF-Endpoint') } || 'share';
		my $file	= File::Spec->catfile($dir, 'www', $path);
		if (-r $file) {
			open( my $fh, '<', $file ) or croak $!;
			$response->status(200);
			$content	= $fh;
		} else {
			my $path	= $req->path;
			$response->status(404);
			$content	= <<"END";
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">\n<html><head>\n<title>404 Not Found</title>\n</head><body>\n
<h1>Not Found</h1>\n<p>The requested URL $path was not found on this server.</p>\n</body></html>
END
		}
		$response->body($content);
		return $response;
	}
	
	my $headers	= $req->headers;
	my $type	= $headers->header('Accept') || 'application/sparql-results+xml';
	if (my $t = $req->param('media-type')) {
		$type	= $t;
		$headers->header('Accept' => $type);
	}
	
	my $ae		= $req->headers->header('Accept-Encoding') || '';
	
	my $sparql;
	my $ct	= $req->header('Content-type');
	if ($req->method !~ /^(GET|POST)$/i) {
		my $method	= uc($req->method);
		$content	= "Unexpected method $method (expecting GET or POST)";
		$self->log_error( $req, $content );
		my $code	= 405;
		$response->status("$code Method Not Allowed");
		$response->body($content);
		goto CLEANUP;
	} elsif (defined($ct) and $ct eq 'application/sparql-query') {
		$sparql	= $req->content;
	} elsif (defined($ct) and $ct eq 'application/sparql-update') {
		if ($config->{endpoint}{update} and $req->method eq 'POST') {
			$sparql	= $req->content;
		}
	} elsif ($req->param('query')) {
		my @sparql	= $req->param('query');
		if (scalar(@sparql) > 1) {
			$content	= "More than one query string submitted";
			$self->log_error( $req, $content );
			my $code	= 400;
			$response->status("$code Multiple Query Strings");
			$response->body($content);
			goto CLEANUP;
		} else {
			$sparql = $sparql[0];
		}
	} elsif ($req->param('update')) {
		my @sparql	= $req->param('update');
		if (scalar(@sparql) > 1) {
			$content	= "More than one update string submitted";
			$self->log_error( $req, $content );
			my $code	= 400;
			$response->status("$code Multiple Update Strings");
			$response->body($content);
			goto CLEANUP;
		}
		
		if ($config->{endpoint}{update} and $req->method eq 'POST') {
			$sparql = $sparql[0];
		} elsif ($req->method ne 'POST') {
			my $method	= $req->method;
			$content	= "Update operations must use POST";
			$self->log_error( $req, $content );
			my $code	= 405;
			$response->status("$code $method Not Allowed for Update Operation");
			$response->body($content);
			goto CLEANUP;
		}
	}
	
	my $ns = merge $config->{namespaces}, $NAMESPACES;

	if ($sparql) {
		my %args;
		$args{ update }		= 1 if ($config->{endpoint}{update} and $req->method eq 'POST');
		$args{ load_data }	= 1 if ($config->{endpoint}{load_data});
		
		my @default	= $req->param('default-graph-uri');
		my @named	= $req->param('named-graph-uri');
		if (scalar(@default) or scalar(@named)) {
			delete $args{ load_data };
			$model	= RDF::Trine::Model->new( RDF::Trine::Store::Memory->new() );
			foreach my $url (@named) {
				RDF::Trine::Parser->parse_url_into_model( $url, $model, context => iri($url) );
			}
			foreach my $url (@default) {
				RDF::Trine::Parser->parse_url_into_model( $url, $model );
			}
		}
		
		my $match	= $headers->header('if-none-match') || '';
		my $etag	= md5_hex( join('#', $self->run_tag, $model->etag, $type, $ae, $sparql) );
		if (length($match)) {
			if (defined($etag) and ($etag eq $match)) {
				$response->status(304);
				return $response;
			}
		}
		
		my $base	= $req->base;
		my $query	= RDF::Query->new( $sparql, { lang => 'sparql11', base => $base, %args } );
		$self->log_query( $req, $sparql );
		if ($query) {
			my ($plan, $ctx)	= $query->prepare( $model );
# 			warn $plan->sse;
			my $iter	= $query->execute_plan( $plan, $ctx );
			if ($iter) {
				$response->status(200);
				if (defined($etag)) {
					$response->headers->header( ETag => $etag );
				}
				if ($iter->isa('RDF::Trine::Iterator::Graph')) {
					my @variants	= (['text/html', 0.99, 'text/html']);
					my %media_types	= %RDF::Trine::Serializer::media_types;
					while (my($type, $sclass) = each(%media_types)) {
						next if ($type =~ /html/);
						my $value	= ($type =~ m#application/rdf[+]xml#) ? 1.00 : 0.98;
						push(@variants, [$type, $value, $type]);
					}
					my $stype	= choose( \@variants, $headers );
					if ($stype !~ /html/ and my $sclass = $RDF::Trine::Serializer::media_types{ $stype }) {
						my $s	= $sclass->new( namespaces => $ns );
						$response->status(200);
						$response->headers->content_type($stype);
						$content	= encode_utf8($s->serialize_iterator_to_string($iter));
					} else {
						$response->headers->content_type( 'text/html' );
						my $html	= $self->iter_as_html($iter, $model);
						$content	= encode_utf8($html);
					}
				} else {
					my @variants	= (
						['text/html', 0.99, 'text/html'],
						['application/sparql-results+xml', 1.0, 'application/sparql-results+xml'],
						['application/json', 0.95, 'application/json'],
						['application/rdf+xml', 0.95, 'application/rdf+xml'],
						['text/turtle', 0.95, 'text/turtle'],
						['text/xml', 0.8, 'text/xml'],
						['application/xml', 0.4, 'application/xml'],
						['text/plain', 0.2, 'text/plain'],
					);
					my $stype	= choose( \@variants, $headers ) || 'application/sparql-results+xml';
					if ($stype =~ /html/) {
						$response->headers->content_type( 'text/html' );
						my $html	= $self->iter_as_html($iter, $model, $sparql);
						$content	= encode_utf8($html);
					} elsif ($stype =~ /xml/) {
						$response->headers->content_type( $stype );
						my $xml		= $self->iter_as_xml($iter, $model);
						$content	= encode_utf8($xml);
					} elsif ($stype =~ /json/) {
						$response->headers->content_type( $stype );
						my $json	= $self->iter_as_json($iter, $model);
						$content	= encode_utf8($json);
					} else {
						$response->headers->content_type( 'text/plain' );
						my $text	= $self->iter_as_text($iter, $model);
						$content	= encode_utf8($text);
					}
				}
			} else {
				my $error	= $query->error;
				$self->log_error( $req, "$error\t$sparql" );
				$response->status(500);
				$response->body($query->error);
				$content	= RDF::Query->error;
			}
		} else {
			$content	= RDF::Query->error;
			$self->log_error( $req, $content );
			my $code	= ($content =~ /Syntax/) ? 400 : 500;
			my $message	= ($code == 400) ? "Syntax Error" : "Internal Server Error";
			$response->status("$code $message");
			$response->body($content);
			if ($req->method ne 'POST' and $content =~ /read-only queries/sm) {
				$content	= 'Updates must use a HTTP POST request.';
			}
		}
	} elsif ($req->method eq 'POST') {
		$content	= "POST without recognized query or update";
		$self->log_error( $req, $content );
		my $code	= 400;
		$response->status("$code Missing SPARQL Query/Update String");
		$response->body($content);
	} else {
		my @variants;
		my %media_types	= %RDF::Trine::Serializer::media_types;
		while (my($type, $sclass) = each(%media_types)) {
			next if ($type =~ /html/);
			push(@variants, [$type, 0.99, $type]);
		}
		push(@variants, ['text/html', 1.0, 'text/html']);
		my $stype	= choose( \@variants, $headers );
		my $sdmodel	= $self->service_description();
		if ($stype !~ /html/ and my $sclass = $RDF::Trine::Serializer::media_types{ $stype }) {
			my $s	= $sclass->new( namespaces => $ns );
			$response->status(200);
			$response->headers->content_type($stype);
			$content	= encode_utf8($s->serialize_model_to_string($sdmodel));
		} else {
			my $dir			= $ENV{RDF_ENDPOINT_SHAREDIR} || eval { dist_dir('RDF-Endpoint') } || 'share';
			my $template	= File::Spec->catfile($dir, 'index.html');
			my $parser		= HTML::HTML5::Parser->new;
			my $doc			= $parser->parse_file( $template );
			my $gen			= RDF::RDFa::Generator->new( style => 'HTML::Head', namespaces => { %$ns } );
			$gen->inject_document($doc, $sdmodel);
			
			my $writer	= HTML::HTML5::Writer->new( markup => 'xhtml', polyglot => 1, doctype => DOCTYPE_XHTML_RDFA );
			$content	= encode_utf8( $writer->document($doc) );
			$response->status(200);
			$response->headers->content_type('text/html');
		}
	}
	
CLEANUP:
	my $length	= 0;
	my %ae		= map { $_ => 1 } split(/\s*,\s*/, $ae);
	if ($ae{'gzip'}) {
		my ($rh, $wh);
		pipe($rh, $wh);
		if (ref($content)) {
			gzip $content => $wh;
		} else {
			gzip \$content => $wh;
		}
		close($wh);
		local($/)	= undef;
		my $body	= <$rh>;
		$length		= bytes::length($body);
		$response->headers->header('Content-Encoding' => 'gzip');
		$response->headers->header('Content-Length' => $length);
		$response->body( $body ) unless ($req->method eq 'HEAD');
	} else {
		local($/)	= undef;
		my $body	= ref($content) ? <$content> : $content;
		$length		= bytes::length($body);
		$response->headers->header('Content-Length' => $length);
		$response->body( $body ) unless ($req->method eq 'HEAD');
	}
	return $response;
}

=item C<< run_tag >>

Returns a unique key for each instantiation of this service.

=cut

sub run_tag {
	my $self	= shift;
	return md5_hex(refaddr($self) . $self->{start_time});
}

=item C<< service_description ( $request, $model ) >>

Returns a new RDF::Trine::Model object containing a service description of this
endpoint, generating dataset statistics from C<< $model >>.

=cut

sub service_description {
	my $self		= shift;
	my $model		= $self->{model};
	my $etag		= $model->etag || '';
	
	if (exists $self->{ sd_cache }) {
		my ($cached_etag, $model) = @{ $self->{ sd_cache } };
		if (defined($cached_etag) and $etag eq $cached_etag) {
			return $model;
		}
	}
	
	my $config		= $self->{conf};
	my $sd			= RDF::Trine::Namespace->new('http://www.w3.org/ns/sparql-service-description#');
	my $void		= RDF::Trine::Namespace->new('http://rdfs.org/ns/void#');
	my $scovo		= RDF::Trine::Namespace->new('http://purl.org/NET/scovo#');
	my $count		= $model->count_statements( undef, undef, undef, RDF::Trine::Node::Nil->new );
	
	my @extensions	= grep { !/kasei[.]us/ } RDF::Query->supported_extensions;
	my @functions	= grep { !/kasei[.]us/ } RDF::Query->supported_functions;
	my @formats		= keys %RDF::Trine::Serializer::format_uris;
	
	my $sdmodel		= RDF::Trine::Model->temporary_model;
	my $s			= blank('service');
	$sdmodel->add_statement( statement( $s, $rdf->type, $sd->Service ) );
	
	$sdmodel->add_statement( statement( $s, $sd->supportedLanguage, $sd->SPARQL11Query ) );
	if ($config->{endpoint}{update}) {
		$sdmodel->add_statement( statement( $s, $sd->supportedLanguage, $sd->SPARQL11Update ) );
	}
	if ($config->{endpoint}{load_data}) {
		$sdmodel->add_statement( statement( $s, $sd->feature, $sd->DereferencesURIs ) );
	}
	
	foreach my $ext (@extensions) {
		$sdmodel->add_statement( statement( $s, $sd->languageExtension, iri($ext) ) );
	}
	foreach my $func (@functions) {
		$sdmodel->add_statement( statement( $s, $sd->extensionFunction, iri($func) ) );
	}
	
	$sdmodel->add_statement( statement( $s, $sd->resultFormat, iri('http://www.w3.org/ns/formats/SPARQL_Results_XML') ) );
	$sdmodel->add_statement( statement( $s, $sd->resultFormat, iri('http://www.w3.org/ns/formats/SPARQL_Results_JSON') ) );
	foreach my $format (@formats) {
		$sdmodel->add_statement( statement( $s, $sd->resultFormat, iri($format) ) );
	}
	
	my $dataset		= blank('dataset');
	$sdmodel->add_statement( statement( $s, $sd->endpoint, iri('') ) );
	$sdmodel->add_statement( statement( $s, $sd->defaultDataset, $dataset ) );
	$sdmodel->add_statement( statement( $dataset, $rdf->type, $sd->Dataset ) );
	if (my $d = $config->{endpoint}{service_description}{default}) {
		my $def_graph	= ($d =~ /^\w+:/) ? iri($d) : blank('defaultGraph');
		$sdmodel->add_statement( statement( $dataset, $sd->defaultGraph, $def_graph ) );
		$sdmodel->add_statement( statement( $def_graph, $rdf->type, $sd->Graph ) );
		$sdmodel->add_statement( statement( $def_graph, $rdf->type, $void->Dataset ) );
		$sdmodel->add_statement( statement( $def_graph, $void->triples, literal( $count, undef, $xsd->integer ) ) );
	}
	if ($config->{endpoint}{service_description}{named_graphs}) {
		my $iter	= $model->get_contexts;
		while (my $g = $iter->next) {
			my $ng		= blank();
			my $graph	= blank();
			my $count	= $model->count_statements( undef, undef, undef, $g );
			$sdmodel->add_statement( statement( $dataset, $sd->namedGraph, $ng ) );
			$sdmodel->add_statement( statement( $ng, $sd->name, $g ) );
			$sdmodel->add_statement( statement( $ng, $sd->graph, $graph ) );
			$sdmodel->add_statement( statement( $graph, $rdf->type, $sd->Graph ) );
			$sdmodel->add_statement( statement( $graph, $rdf->type, $void->Dataset ) );
			$sdmodel->add_statement( statement( $graph, $void->triples, literal( $count, undef, $xsd->integer ) ) );
		}
	}
	
	$self->{ sd_cache }	= [ $etag, $sdmodel ];
	return $sdmodel;
}

=begin private

=item C<< iter_as_html ( $iter, $model ) >>

=cut

sub iter_as_html {
	my $self	= shift;
	my $stream	= shift;
	my $model	= shift;
	my $query	= shift;

	my $dir  = $ENV{RDF_ENDPOINT_SHAREDIR} || eval { dist_dir('RDF-Endpoint') } || 'share';
	my $file = File::Spec->catfile($dir, 'results.html');
	my $html;

	if (-r $file) {
		open( my $fh, '<', $file ) or croak $!;
		$html = do { local $/; <$fh>; };
		close $fh;
	} else {
		$html = <<HTML
<html><head><title>SPARQL Results</title></head><body>
<div id="result" />
<h2>Query</h2> 
<form id="queryform" action="" method="get"> 
<p><textarea id="query" name="query" rows="10" cols="60"></textarea>
<br/>
<select id="media-type" name="media-type"> 
    <option value="">Result Format...</option> 
    <option label="HTML" value="text/html">HTML</option> 
    <option label="Turtle" value="text/turtle">Turtle</option> 
    <option label="XML" value="text/xml">XML</option> 
    <option label="JSON" value="application/json">JSON</option> 
</select> 
<input name="submit" id="submit" type="submit" value="Submit" /> 
</p>
</form>
</body></html>
HTML
	}

	my $result = "<h2>Result</h2>\n";

	if ($stream->isa('RDF::Trine::Iterator::Boolean')) {
		$result	= (($stream->get_boolean) ? "True" : "False");
	} elsif ($stream->isa('RDF::Trine::Iterator::Bindings')) {
		$result = "<table class='tablesorter'>\n<thead><tr>\n";
		
		my @names	= $stream->binding_names;
		my $columns	= scalar(@names);
		foreach my $name (@names) {
			$result	.= "\t<th>" . $name . "</th>\n";
		}
		$result	.= "</tr></thead>\n";
		
		my $count	= 0;
		while (my $row = $stream->next) {
			$count++;
			$result	.= "<tr>\n";
			foreach my $k (@names) {
				my $node	= $row->{ $k };
				my $value	= $self->node_as_html($node, $model);
				$result	.= "\t<td>" . $value . "</td>\n";
			}
			$result	.= "</tr>\n";
		}
		$result   .= "<tfoot><tr><th colspan=\"$columns\">Total: $count</th></tr></tfoot>\n</table>\n";	
	}

	$html =~ s/<div\s+id\s*=\s*["']result["']\s*\/>/<div id="result">$result<\/div>/;
	$html =~ s/(<textarea[^>]*>)(.|\n)*(<\/textarea>)/$1$query$3/sm;

	return $html;
}

=item C<< iter_as_text ( $iter ) >>

=cut

sub iter_as_text {
	my $self	= shift;
	my $iter	= shift;
	if ($iter->isa('RDF::Trine::Iterator::Graph')) {
		my $serializer	= RDF::Trine::Serializer->new('ntriples');
		return $serializer->serialize_iterator_to_string( $iter );
	} else {
		return $iter->as_string;
	}
}

=item C<< iter_as_xml ( $iter ) >>

=cut

sub iter_as_xml {
	my $self	= shift;
	my $iter	= shift;
	return $iter->as_xml;
}

=item C<< iter_as_json ( $iter ) >>

=cut

sub iter_as_json {
	my $self	= shift;
	my $iter	= shift;
	return $iter->as_json;
}

=item C<< node_as_html ( $node, $model ) >>

=cut

sub node_as_html {
	my $self	= shift;
	my $node	= shift;
	my $model	= shift;
	my $config	= $self->{conf};
	return '' unless (blessed($node));
	if ($node->isa('RDF::Trine::Node::Resource')) {
		my $uri	= $node->uri_value;
		for ($uri) {
			s/&/&amp;/g;
			s/</&lt;/g;
		}
		my $link	= $config->{endpoint}{html}{resource_links};
		my $html;
		if ($config->{endpoint}{html}{embed_images}) {
			if ($model->count_statements( $node, iri('http://www.w3.org/1999/02/22-rdf-syntax-ns#type'), iri('http://xmlns.com/foaf/0.1/Image') )) {
				my $width	= $config->{endpoint}{html}{image_width} || 200;
				$html	= qq[<img src="${uri}" width="${width}" />];
			} else {
				$html	= $uri;
			}
		} else {
			$html	= $uri;
		}
		if ($link) {
			$html	= qq[<a href="${uri}">$html</a>];
		}
		return $html;
	} elsif ($node->isa('RDF::Trine::Node::Literal')) {
		my $html	= $node->literal_value;
		for ($html) {
			s/&/&amp;/g;
			s/</&lt;/g;
		}
		return $html;
	} else {
		my $html	= $node->as_string;
		for ($html) {
			s/&/&amp;/g;
			s/</&lt;/g;
		}
		return $html;
	}
}

=item C<< log_query ( $message ) >>

=cut

sub log_query {
	my $self	= shift;
	my $req		= shift;
	my $message	= shift;
	$self->_log( $req, { level => 'info', message => $message } );
}

=item C<< log_error ( $message ) >>

=cut

sub log_error {
	my $self	= shift;
	my $req		= shift;
	my $message	= shift;
	$self->_log( $req, { level => 'error', message => $message } );
}

sub _log {
	my $self	= shift;
	my $req		= shift;
	my $data	= shift;
	my $logger	= $req->logger || sub {};
	
	$logger->($data);
}

=end private

=cut

1;

__END__

=back

=head1 SEE ALSO

=over 4

=item * L<http://www.w3.org/TR/sparql11-protocol/>

=item * L<http://www.perlrdf.org/>

=item * L<irc://irc.perl.org/#perlrdf>

=item * L<http://codemirror.net/>

=back

=head1 AUTHOR

 Gregory Todd Williams <gwilliams@cpan.org>

=head1 LICENSE AND COPYRIGHT

Copyright (c) 2010-2012 Gregory Todd Williams.

This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any
damages arising from the use of this software.

Permission is granted to anyone to use this software for any
purpose, including commercial applications, and to alter it and
redistribute it freely, subject to the following restrictions:

1. The origin of this software must not be misrepresented; you must
   not claim that you wrote the original software. If you use this
   software in a product, an acknowledgment in the product
   documentation would be appreciated but is not required.

2. Altered source versions must be plainly marked as such, and must
   not be misrepresented as being the original software.

3. This notice may not be removed or altered from any source
   distribution.

With the exception of the CodeMirror files, the files in this package may also
be redistributed and/or modified under the same terms as Perl itself.

The CodeMirror (Javascript and CSS) files contained in this package are
copyright (c) 2007-2010 Marijn Haverbeke, and licensed under the terms of the
same zlib license as this code.

=cut