index.php

<?php
define('MORIARTY_ARC_DIR', 'arc/');
require_once 'moriarty/moriarty.inc.php';
require_once 'moriarty/simplegraph.class.php';

function sort_accept_values($header_list) {
	if (empty($header_list)) { return array(); }
	$entries = explode(',', $header_list);
	foreach ($entries as $entry) {
		$parts = explode(';', $entry);
		$values[$parts[0]] = isset($parts[1]) ? trim(str_replace('q=', '', $parts[1])) : 1;
	}
	arsort($values, SORT_NUMERIC);
	return array_keys($values);
}

//redirect / to /schema
$requested_uri = 'http://linkedrecipes.org'.$_SERVER['REQUEST_URI'];
if ($requested_uri == 'http://linkedrecipes.org/') {
	header("HTTP/1.1 303 See Other");
	header('Location: '.$requested_uri.'schema');
	exit;
}

$requested_mime_types = sort_accept_values($_SERVER['HTTP_ACCEPT']);
$acceptable_mime_types = array('text/html', 'application/rdf+xml', 'text/turtle', 'application/json', '*/*');
$possible_mime_types = array_intersect($requested_mime_types, $acceptable_mime_types);
if (empty($possible_mime_types)) { require_once 'errors/406NotAcceptable.php'; exit; }
$chosen_mime_type = array_shift($possible_mime_types);
if ($chosen_mime_type == '*/*') { $chosen_mime_type = 'text/html'; }

$extensions = array('text/html' => '.html', 'application/rdf+xml' => '.rdf', 'text/turtle' => '.n3', 'application/json' => '.json');
foreach ($extensions as $mime_type => $extension) {
	if (preg_match("%${extension}\$%", $requested_uri) && $mime_type == $chosen_mime_type) {
		$requested_uri = str_replace($extension, '', $requested_uri);
		$_SERVER['REQUEST_URI'] = str_replace($extension, '', $_SERVER['REQUEST_URI']);
	} else if (preg_match("%${extension}\$%", $requested_uri)) {
		$requested_uri = str_replace($extension, '', $requested_uri);
		header("HTTP/1.1 303 See Other");
		header('Location: '.$requested_uri.$extensions[$chosen_mime_type]);
		exit;
	}
}

$turtle_path = './schema.ttl';
$turtle = file_get_contents($turtle_path);
$complete_graph = new SimpleGraph();
$complete_graph->from_turtle($turtle);
preg_match_all('%/[^/]+%', $_SERVER['REQUEST_URI'], $request_parts);
list($ontology_part, $property_or_class_part, $value_part) = $request_parts[0];
$is_ontology_request = isset($ontology_part) && !isset($property_or_class_part) ? true : false ;
$is_property_or_class_request = isset($property_or_class_part) && !isset($value_part) ? true : false ;
$ontology_uri = isset($ontology_part) ? 'http://linkedrecipes.org'.$ontology_part : null ;
$property_or_class_uri = isset($property_or_class_part) ? $ontology_uri.$property_or_class_part : null ;

if (!$complete_graph->has_triples_about($ontology_uri)) { require_once 'errors/404NotFound.php'; exit; }
if (!$is_ontology_request && !$complete_graph->has_triples_about($property_or_class_uri)) { require_once 'errors/404NotFound.php'; exit; }
if ($is_property_or_class_request && $chosen_mime_type == 'text/html') { header('Location: '.$ontology_uri.preg_replace('%/%', '#', $property_or_class_part)); exit; }

$content_location = $requested_uri;
$content_location .= preg_match('%/$%', $requested_uri) ? 'index' : '';
$content_location .= $extensions[$chosen_mime_type];

header("Content-type: ${chosen_mime_type}");
header("Content-location: ${content_location}");

$graph_to_serve = $complete_graph->get_subject_subgraph($requested_uri);
$graph_to_serve->set_namespace_mapping('recipe', 'http://linkedrecipes.org/schema/');
$graph_to_serve->set_namespace_mapping('cc', 'http://web.resource.org/cc/');
switch ($chosen_mime_type) {
	case 'application/rdf+xml':
		echo $graph_to_serve->to_rdfxml(); break;
	case 'text/turtle':
		echo $graph_to_serve->to_turtle(); break;
	case 'application/json':
		echo $graph_to_serve->to_json(); break;
	default:
		require_once 'text-html.php'; break;
}