/**
* Retrieve a Data object identified by $uri
*
* @param string $uri The identifier that identifies a resource
*
* @return \Response
*/
public function get($uri)
{
// Check permissions
Auth::requirePermissions('dataset.view');
// Split for an (optional) extension
list($uri, $extension) = $this->processURI($uri);
// Check for caching
// Based on: URI / Rest parameters / Query parameters / Paging headers
$cache_string = $uri;
list($limit, $offset) = Pager::calculateLimitAndOffset();
$cache_string .= '/limit=' . $limit . 'offset=' . $offset;
$cache_string .= http_build_query(\Input::except('limit', 'offset', 'page', 'page_size'));
$cache_string = sha1($cache_string);
if (Cache::has($cache_string)) {
return ContentNegotiator::getResponse(Cache::get($cache_string), $extension);
} else {
// Get definition
$definition = $this->definition->getByIdentifier($uri);
if ($definition) {
// Get source definition
$source_definition = $this->definition->getDefinitionSource($definition['source_id'], $definition['source_type']);
if ($source_definition) {
$source_type = $source_definition['type'];
// Create the right datacontroller
$controller_class = 'Tdt\\Core\\DataControllers\\' . $source_type . 'Controller';
$data_controller = \App::make($controller_class);
// Get REST parameters
$rest_parameters = str_replace($definition['collection_uri'] . '/' . $definition['resource_name'], '', $uri);
$rest_parameters = ltrim($rest_parameters, '/');
$rest_parameters = explode('/', $rest_parameters);
if (empty($rest_parameters[0]) && !is_numeric($rest_parameters[0])) {
$rest_parameters = array();
}
// Retrieve dataobject from datacontroller
$data = $data_controller->readData($source_definition, $rest_parameters);
$data->rest_parameters = $rest_parameters;
// REST filtering
if ($source_type != 'INSTALLED' && count($data->rest_parameters) > 0) {
$data->data = self::applyRestFilter($data->data, $data->rest_parameters);
}
// Add definition to the object
$data->definition = $definition;
// Add source definition to the object
$data->source_definition = $source_definition;
// Add the available, supported formats to the object
$format_helper = new FormatHelper();
$data->formats = $format_helper->getAvailableFormats($data);
// Store in cache
Cache::put($cache_string, $data, $source_definition['cache']);
// Return the formatted response with content negotiation
return ContentNegotiator::getResponse($data, $extension);
} else {
\App::abort(404, "Source for the definition could not be found.");
}
} else {
// Coulnd't find a definition, but it might be a collection
$resources = $this->definition->getByCollection($uri);
if (count($resources) > 0) {
$data = new Data();
$data->data = new \stdClass();
$data->data->datasets = array();
$data->data->collections = array();
foreach ($resources as $res) {
// Check if it's a subcollection or a dataset
$collection_uri = rtrim($res['collection_uri'], '/');
if ($collection_uri == $uri) {
array_push($data->data->datasets, \URL::to($collection_uri . '/' . $res['resource_name']));
} else {
// Push the subcollection if it's not already in the array
if (!in_array(\URL::to($collection_uri), $data->data->collections)) {
array_push($data->data->collections, \URL::to($collection_uri));
}
}
}
// Fake a definition
$data->definition = new \Definition();
$uri_array = explode('/', $uri);
$last_chunk = array_pop($uri_array);
$data->definition->collection_uri = join('/', $uri_array);
$data->definition->resource_name = $last_chunk;
// Return the formatted response with content negotiation
return ContentNegotiator::getResponse($data, $extension);
} else {
\App::abort(404, "The dataset or collection you were looking for could not be found (URI: {$uri}).");
}
}
}
}
public function getDescriptionInfo($identifier)
{
$definition = $this->getEloquentDefinition($identifier);
$properties = array();
$source_definition = $definition->source()->first();
foreach ($definition->getFillable() as $key) {
$properties[$key] = $definition->{$key};
}
$properties['type'] = strtolower($source_definition->type);
$properties['description'] = @$source_definition->description;
// Get the formats based on the source definition meta-data
$format_helper = new FormatHelper();
$formats = $format_helper->getFormatsForType($source_definition->toArray());
$properties['formats'] = $formats;
$properties['identifier'] = $identifier;
unset($properties['map_property']);
return $properties;
}
/**
* Retrieve a Data object identified by $uri
*
* @param string $uri The identifier that identifies a resource
*
* @return \Response
*/
public function get($uri)
{
// Check permissions
Auth::requirePermissions('dataset.view');
// Split for an (optional) extension
list($uri, $extension) = $this->processURI($uri);
// Check for caching
// Based on: URI / Rest parameters / Query parameters / Paging headers
$cache_string = $uri;
list($limit, $offset) = Pager::calculateLimitAndOffset();
$cache_string .= '/limit=' . $limit . 'offset=' . $offset;
$omit = ['limit', 'offset', 'page', 'page_size'];
$query_string_params = \Input::get();
foreach ($query_string_params as $key => $val) {
if (in_array($key, $omit)) {
unset($query_string_params[$key]);
}
}
$cache_string .= http_build_query($query_string_params);
$cache_string = sha1($cache_string);
if (Cache::has($cache_string)) {
return ContentNegotiator::getResponse(Cache::get($cache_string), $extension);
} else {
// Get definition
$definition = $this->definition->getByIdentifier($uri);
if ($definition) {
// Get source definition
$source_definition = $this->definition->getDefinitionSource($definition['source_id'], $definition['source_type']);
if ($source_definition) {
$source_type = $source_definition['type'];
// Create the right datacontroller
$controller_class = 'Tdt\\Core\\DataControllers\\' . $source_type . 'Controller';
$data_controller = \App::make($controller_class);
// Get REST parameters
$uri_segments = explode('/', $uri);
$rest_parameters = array_diff($uri_segments, array($definition['collection_uri'], $definition['resource_name']));
$rest_parameters = array_values($rest_parameters);
$throttle_response = $this->applyThrottle($definition);
if (!empty($throttle_response)) {
return $throttle_response;
}
// Retrieve dataobject from datacontroller
$data = $data_controller->readData($source_definition, $rest_parameters);
// If the source type is XML, just return the XML contents, don't transform
if (strtolower($source_type) == 'xml' && $extension == 'xml') {
return $this->createXMLResponse($data->data);
}
$data->rest_parameters = $rest_parameters;
// REST filtering
if ($source_type != 'INSTALLED' && count($data->rest_parameters) > 0) {
$data->data = self::applyRestFilter($data->data, $data->rest_parameters);
}
// Semantic paging with the hydra voc
if ($data->is_semantic && !empty($data->paging)) {
\EasyRdf_Namespace::set('hydra', 'http://www.w3.org/ns/hydra/core#');
$graph = $data->data;
$url = \URL::to($definition['collection_uri'] . '/' . $definition['resource_name']);
$request_url = \Request::url();
$graph->addResource($request_url, 'void:subset', $url);
foreach ($data->paging as $key => $val) {
$paged_url = $request_url . '?offset=' . $val[0] . '&limit=' . $val[1] . Pager::buildQuerystring();
switch ($key) {
case 'next':
$graph->addResource($request_url, 'hydra:nextPage', $paged_url);
break;
case 'previous':
$graph->addResource($request_url, 'hydra:previousPage', $paged_url);
break;
case 'last':
$graph->addResource($request_url, 'hydra:lastPage', $paged_url);
break;
case 'first':
$graph->addResource($request_url, 'hydra:firstPage', $paged_url);
break;
}
}
$graph->addResource($url, 'a', 'dcat:Dataset');
$title = null;
if (!empty($definition['title'])) {
$title = $definition['title'];
} else {
$title = $definition['collection_uri'] . '/' . $definition['resource_name'];
}
$graph->addLiteral($url, 'dc:title', $title);
$graph->addLiteral($url, 'dc:description', $source_definition['description']);
$graph->addResource($url, 'dcat:distribution', $url . '.json');
$data->data = $graph;
}
// Add definition to the object
$data->definition = $definition;
// Add source definition to the object
$data->source_definition = $source_definition;
// Add the available, supported formats to the object
$format_helper = new FormatHelper();
$data->formats = $format_helper->getAvailableFormats($data);
// Store in cache
Cache::put($cache_string, $data, $source_definition['cache']);
// Return the formatted response with content negotiation
return ContentNegotiator::getResponse($data, $extension);
} else {
\App::abort(404, "Source for the definition could not be found.");
}
} else {
// Coulnd't find a definition, but it might be a collection
$resources = $this->definition->getByCollection($uri);
if (count($resources) > 0) {
$data = new Data();
$data->data = new \stdClass();
$data->data->datasets = array();
$data->data->collections = array();
foreach ($resources as $res) {
// Check if it's a subcollection or a dataset
$collection_uri = rtrim($res['collection_uri'], '/');
if ($collection_uri == $uri) {
array_push($data->data->datasets, \URL::to($collection_uri . '/' . $res['resource_name']));
} else {
// Push the subcollection if it's not already in the array
if (!in_array(\URL::to($collection_uri), $data->data->collections)) {
array_push($data->data->collections, \URL::to($collection_uri));
}
}
}
// Fake a definition
$data->definition = new \Definition();
$uri_array = explode('/', $uri);
$last_chunk = array_pop($uri_array);
$data->definition->collection_uri = join('/', $uri_array);
$data->definition->resource_name = $last_chunk;
// Return the formatted response with content negotiation
return ContentNegotiator::getResponse($data, $extension);
} else {
\App::abort(404, "The dataset or collection you were looking for could not be found (URI: {$uri}).");
}
}
}
}
/**
* Format using requested formatter (via extension, Accept-header or default)
*
* @param Tdt\Core\Datasets\Data $data The data object on which the response will be based
* @param string $extension The preferred format in which the data should be returned
*
* @return \Response
*/
public static function getResponse($data, $extension = null)
{
// Check Accept-header
$accept_header = \Request::header('Accept');
// Safety first
$extension = strtoupper($extension);
// Formatter class
$formatter_class = 'Tdt\\Core\\Formatters\\' . $extension . 'Formatter';
if (empty($extension)) {
$negotiator = new FormatNegotiator();
foreach (self::$mime_types_map as $format_name => $mime_types) {
$negotiator->registerFormat($format_name, $mime_types, true);
}
// Create a priority list of formats
$priorities = array();
$format_helper = new FormatHelper();
if (empty($data->preferred_formats)) {
// Still nothing? Use default formatter
if (empty($extension) && !$data->is_semantic) {
// Default formatter for non semantic data
$data->preferred_formats = array('json');
} elseif (empty($extension) && $data->is_semantic) {
// Default formatter for semantic data is turtle
$data->preferred_formats = array('ttl');
}
}
if (!in_array('html', $priorities)) {
array_push($priorities, 'html');
}
$priorities = array_merge($data->preferred_formats, $priorities);
// Add support for our other formatters as well, if they're not already in the priorities
foreach ($format_helper->getAvailableFormats($data) as $format) {
if (!in_array($format, $priorities)) {
array_push($priorities, $format);
}
}
array_push($priorities, '*/*');
$format = $negotiator->getBestFormat($accept_header, $priorities);
$format_object = $negotiator->getBest($accept_header, $priorities);
if (!$format || $format_object->getQuality() == 0) {
$format_helper = new FormatHelper();
$available_formats = implode(', ', array_values($format_helper->getAvailableFormats($data)));
\App::abort(406, "The requested Content-Type is not supported, or the best quality we found was 0. The supported formats for this resource are: " . $available_formats);
}
// Safety first
$extension = strtoupper($format);
// Formatter class
$formatter_class = 'Tdt\\Core\\Formatters\\' . $extension . 'Formatter';
} elseif (!class_exists($formatter_class)) {
$format_helper = new FormatHelper();
$available_formats = implode(', ', array_values($format_helper->getAvailableFormats($data)));
\App::abort(406, "The requested Content-Type is not supported, or the best quality we found was 0. The supported formats for this resource are: " . $available_formats);
}
// Create the response from the designated formatter
$response = $formatter_class::createResponse($data);
// Set the paging header
if (!empty($data->paging)) {
$response->header('Link', self::getLinkHeader($data->paging));
}
// Set the URI template header
if (!empty($data->optional_parameters) || !empty($data->rest_parameters)) {
// http://www.mnot.net/blog/2006/10/04/uri_templating
$link_template = self::fetchUrl($extension);
if (substr($link_template, -1, 1) == '/') {
$link_template = substr($link_template, 0, -1);
}
// Add the required parameters
foreach ($data->rest_parameters as $required_parameter) {
$link_template .= '/{' . $required_parameter . '}';
}
// Add the extension if given
if (!empty($extension)) {
$link_template .= '.' . strtolower($extension);
}
// Add the optional parameters
if (!empty($data->optional_parameters)) {
$link_template .= '{?';
foreach ($data->optional_parameters as $optional_parameter) {
$link_template .= $optional_parameter . ', ';
}
$link_template = rtrim($link_template, ', ');
$link_template .= '}';
}
$response->header('Link-Template', $link_template);
}
// Cache settings
$cache_minutes = -1;
if (\Config::get('cache.enabled', true)) {
$cache_minutes = 1;
// Cache per resource
if (!empty($data->source_definition['cache'])) {
$cache_minutes = $data->source_definition['cache'];
}
}
// Cache headers
$response->header('Cache-Control', 'public, max-age=' . $cache_minutes * 60 . ', pre-check=' . $cache_minutes * 60 . '');
$response->header('Pragma', 'public');
$response->header('Expires', date(DATE_RFC822, strtotime("{$cache_minutes} minute")));
$response->header('Vary', 'Accept, Accept-encoding');
// Return formatted response
return $response;
}
/**
* Resolve a graph pattern query (/all route)
*
* @param string $format The format of the request
*
* @return \Response
*/
public function solveQuery($format = null)
{
$data;
if (!empty($format)) {
$format = ltrim($format, '.');
}
// Ignore the rest of the uri after /all and work with the request parameters as they were given
$cache_string = sha1($this->getRawRequestURI(\Request::root()));
// Check if the response to the query has been cached already
if (Cache::has($cache_string)) {
$data = Cache::get($cache_string);
} else {
// Get the graph pattern query string parameters from the request
list($s, $p, $o) = $this->getTemplateParameters();
// Pass them to our sparql query builder
SparqlQueryBuilder::setParameters(array($s, $p, $o));
$base_uri = null;
// If no parameter has been filled in, the URI we have to match triples with is the root of our application
if ($s == '?s' && $p == '?p' && $o == '?o') {
$base_uri = \Request::root();
}
// Fetch matching triples
$result = $this->triples->getTriples($base_uri, \Request::get('limit', 100), \Request::get('offset', 0));
// If the graph contains no triples, then the graph pattern couldn't resolve to anything, 404 it is
if ($result->countTriples() == 0) {
\App::abort(404, "The resource couldn't be found, nor dereferenced.");
}
$definition = array('resource_name' => "all", 'collection_uri' => "");
$source_definition = array('description' => 'Semantic data collected out the configured semantic data sources.', 'type' => 'Semantic');
$data = new Data();
$data->definition = $definition;
$data->source_definition = $source_definition;
$data->data = $result;
$data->is_semantic = true;
// Add the available, supported formats to the object
$format_helper = new FormatHelper();
$data->formats = $format_helper->getAvailableFormats($data);
// Store in cache for a default of 5 minutes
Cache::put($cache_string, $data, 5);
}
// Add the hydra namespace, it's not present in the easy rdf namespaces by default
\EasyRdf_Namespace::set('hydra', 'http://www.w3.org/ns/hydra/core#');
// Return the formatted response with content negotiation
$response = ContentNegotiator::getResponse($data, $format);
// Pass a Vary header so that browsers know they have to take the accept header
// into consideration when they apply caching client side
$response->header('Vary', 'Accept');
// Allow CORS
$response->header('Access-Control-Allow-Origin', '*');
return $response;
}
