/**
* This method sends a SPARQL query to the store.
*
* @param string $query The SPARQL query to send to the store.
* @param array $options optional It contains key-value pairs and should provide additional
* introductions for the store and/or its adapter(s).
* @return Result Returns result of the query. Its type depends on the type of the query.
* @throws \Exception If query is no string.
* @throws \Exception If query is malformed.
* @throws StoreException If server returned an error.
* @todo add support for DESCRIBE queries
*/
public function query($query, array $options = array())
{
$queryObject = $this->queryFactory->createInstanceByQueryString($query);
$queryParts = $queryObject->getQueryParts();
/**
* SPARQL query (usually to fetch data)
*/
if ('selectQuery' == AbstractQuery::getQueryType($query)) {
$resultArray = json_decode($this->client->sendSparqlSelectQuery($query), true);
$entries = array();
/**
* go through all bindings and create according objects for SetResult instance.
*
* $bindingParts will look like:
*
* array(
* 's' => array(
* 'type' => 'uri',
* 'value' => '...'
* ), ...
* )
*/
foreach ($resultArray['results']['bindings'] as $bindingParts) {
$newEntry = array();
/**
* A part looks like:
* array(
* 'type' => 'uri',
* 'value' => '...'
* )
*/
foreach ($bindingParts as $variable => $part) {
switch ($part['type']) {
/**
* Literal (language'd)
*/
case 'literal':
$lang = null;
if (isset($part['xml:lang'])) {
$lang = $part['xml:lang'];
}
$newEntry[$variable] = $this->nodeFactory->createLiteral($part['value'], 'http://www.w3.org/1999/02/22-rdf-syntax-ns#langString', $lang);
break;
/**
* Typed-Literal
*/
/**
* Typed-Literal
*/
case 'typed-literal':
$newEntry[$variable] = $this->nodeFactory->createLiteral($part['value'], $part['datatype']);
break;
/**
* NamedNode
*/
/**
* NamedNode
*/
case 'uri':
$newEntry[$variable] = $this->nodeFactory->createNamedNode($part['value']);
break;
/**
* BlankNode
*/
/**
* BlankNode
*/
case 'bnode':
$newEntry[$variable] = $this->nodeFactory->createBlankNode($part['value']);
break;
default:
throw new \Exception('Unknown type given.');
break;
}
}
$entries[] = $newEntry;
}
$return = $this->resultFactory->createSetResult($entries);
$return->setVariables($resultArray['head']['vars']);
/**
* SPARPQL Update query
*/
} else {
$result = $this->client->sendSparqlUpdateQuery($query);
$decodedResult = json_decode($result, true);
if ('askQuery' === AbstractQuery::getQueryType($query)) {
$askResult = json_decode($result, true);
if (true === isset($askResult['boolean'])) {
$return = $this->resultFactory->createValueResult($askResult['boolean']);
// assumption here is, if a string was returned, something went wrong.
} elseif (0 < strlen($result)) {
throw new \Exception($result);
} else {
$return = $this->resultFactory->createEmptyResult();
}
// usually a SPARQL result does not return a string. if it does anyway, assume there is an error.
} elseif (null === $decodedResult && 0 < strlen($result)) {
throw new \Exception($result);
} else {
$return = $this->resultFactory->createEmptyResult();
}
}
return $return;
}
