/**
* {@inheritdoc}
*/
public function buildForm(array $form, FormStateInterface $form_state)
{
$export_types = $this->config('rdf_export.settings')->get('export_types');
// @todo: Check which format are supported by the server?
$formats = Format::getFormats();
$list = [];
/** @var \EasyRdf\Format $format */
foreach ($formats as $format) {
if ($format->getSerialiserClass()) {
$list[$format->getName()] = $format->getLabel();
}
}
$form['export_types'] = array('#type' => 'select', '#title' => t('Export types'), '#options' => $list, '#multiple' => TRUE, '#default_value' => empty($export_types) ? [] : $export_types, '#description' => t('Select the export types for rdf entities.'));
return parent::buildForm($form, $form_state);
}
}
}
/**
* Serialise an EasyRdf\Graph into RDF format of choice.
*
* @param Graph $graph An EasyRdf\Graph object.
* @param string $format The name of the format to convert to.
* @param array $options
*
* @throws Exception
*
* @return string The RDF in the new desired format.
*/
public function serialise($graph, $format, array $options = array())
{
parent::checkSerialiseParams($graph, $format);
if (array_key_exists($format, self::$supportedTypes)) {
$className = self::$supportedTypes[$format];
} else {
throw new Exception("EasyRdf\\Serialiser\\Arc does not support: {$format}");
}
$serialiser = \ARC2::getSer($className);
if ($serialiser) {
return $serialiser->getSerializedIndex(parent::serialise($graph, 'php'));
} else {
throw new Exception("ARC2 failed to get a {$className} serialiser.");
}
}
}
Format::register('posh', 'poshRDF');
/**
* Builds a list of supported serialization formats.
*/
protected function getSerializerFormats()
{
// Many more are supported...
// @todo Move this to a settings form.
$white_list = $this->config('rdf_export.settings')->get('export_types');
$list = [];
$formats = Format::getFormats();
/** @var \EasyRdf\Format $format */
foreach ($formats as $format) {
if (!in_array($format->getName(), $white_list)) {
continue;
}
if ($format->getSerialiserClass()) {
$list[$format->getName()] = $format;
}
}
return $list;
}
/**
* Parses a given stream and returns an iterator containing Statement instances representing the
* previously read data. The stream parses the data not as a whole but in chunks.
*
* @param string $inputStream Filename of the stream to parse which contains RDF
* serialized data.
* @param string $baseUri The base URI of the parsed content. If this URI is null
* the inputStreams URL is taken as base URI.
* @param string $serialization The serialization of the inputStream. If null is given
* the parser will either apply some standard serialization,
* or the only one it is supporting, or will try to guess
* the correct serialization, or will throw an Exception.
* Supported formats are a subset of the following:
* json, rdfxml, sparql-xml, rdfa, turtle, ntriples, n3
* @return StatementIterator A StatementIterator containing all the Statements parsed by the parser to
* far.
* @throws \Exception If the base URI $baseUri is no valid URI.
*/
public function parseStreamToIterator($inputStream, $baseUri = null, $serialization = null)
{
$graph = new Graph();
// let EasyRdf guess the format
if ($serialization === null) {
// use PHP's file:// stream, if its a local file
if (false === strpos($inputStream, '://')) {
$inputStream = 'file://' . $inputStream;
}
$serialization = Format::guessFormat(file_get_contents($inputStream));
} else {
$serialization = Format::getFormat($serialization);
}
// if format is still null, throw exception, because we dont know what format the given stream is
if (null === $serialization) {
throw new \Exception('Either given $format is unknown or i could not guess format.');
}
$graph->parseFile($inputStream, $serialization->getName());
// transform parsed data to PHP array
return $this->rdfPhpToStatementIterator($graph->toRdfPhp());
}
<?php
use EasyRdf\Graph;
use EasyRdf\Format;
use EasyRdf\Serialiser\GraphViz;
$app->get('/image', function () {
$graph = Graph::newAndLoad(site_base_uri() . '/asset/dataset/countries.rdf');
$format = Format::getFormat('png');
$viz = new GraphViz();
header("Content-Type: " . $format->getDefaultMimeType());
echo $viz->renderImage($graph, $format);
die;
})->name('home');
/**
* Build http-client object, execute request and return a response
*
* @param string $processed_query
* @param string $type Should be either "query" or "update"
*
* @return Http\Response|\Zend\Http\Response
* @throws Exception
*/
protected function executeQuery($processed_query, $type)
{
$client = Http::getDefaultHttpClient();
$client->resetParameters();
// Tell the server which response formats we can parse
$sparql_results_types = array('application/sparql-results+json' => 1.0, 'application/sparql-results+xml' => 0.8);
if ($type == 'update') {
// accept anything, as "response body of a […] update request is implementation defined"
// @see http://www.w3.org/TR/sparql11-protocol/#update-success
$accept = Format::getHttpAcceptHeader($sparql_results_types);
$client->setHeaders('Accept', $accept);
$client->setMethod('POST');
$client->setUri($this->updateUri);
$client->setRawData($processed_query);
$client->setHeaders('Content-Type', 'application/sparql-update');
} elseif ($type == 'query') {
$re = '(?:(?:\\s*BASE\\s*<.*?>\\s*)|(?:\\s*PREFIX\\s+.+:\\s*<.*?>\\s*))*' . '(CONSTRUCT|SELECT|ASK|DESCRIBE)[\\W]';
$result = null;
$matched = mb_eregi($re, $processed_query, $result);
if (false === $matched or count($result) !== 2) {
// non-standard query. is this something non-standard?
$query_verb = null;
} else {
$query_verb = strtoupper($result[1]);
}
if ($query_verb === 'SELECT' or $query_verb === 'ASK') {
// only "results"
$accept = Format::formatAcceptHeader($sparql_results_types);
} elseif ($query_verb === 'CONSTRUCT' or $query_verb === 'DESCRIBE') {
// only "graph"
$accept = Format::getHttpAcceptHeader();
} else {
// both
$accept = Format::getHttpAcceptHeader($sparql_results_types);
}
$client->setHeaders('Accept', $accept);
$encodedQuery = 'query=' . urlencode($processed_query);
// Use GET if the query is less than 2kB
// 2046 = 2kB minus 1 for '?' and 1 for NULL-terminated string on server
if (strlen($encodedQuery) + strlen($this->queryUri) <= 2046) {
$delimiter = $this->queryUri_has_params ? '&' : '?';
$client->setMethod('GET');
$client->setUri($this->queryUri . $delimiter . $encodedQuery);
} else {
// Fall back to POST instead (which is un-cacheable)
$client->setMethod('POST');
$client->setUri($this->queryUri);
$client->setRawData($encodedQuery);
$client->setHeaders('Content-Type', 'application/x-www-form-urlencoded');
}
} else {
throw new Exception('unexpected request-type: ' . $type);
}
return $client->request();
}
