/**
* Serialise an EasyRdf_Graph to the RDF format of choice.
*
* @param object EasyRdf_Graph $graph An EasyRdf_Graph object.
* @param string $format The name of the format to convert to.
* @return string The RDF in the new desired format.
*/
public function serialise($graph, $format)
{
parent::checkSerialiseParams($graph, $format);
$ntriples = parent::serialise($graph, 'ntriples');
// Open a pipe to the rapper command
$descriptorspec = array(0 => array("pipe", "r"), 1 => array("pipe", "w"), 2 => array("pipe", "w"));
// Hack to produce more concise RDF/XML
if ($format == 'rdfxml') {
$format = 'rdfxml-abbrev';
}
$process = proc_open(escapeshellcmd($this->_rapperCmd) . " --quiet " . " --input ntriples " . " --output " . escapeshellarg($format) . " - " . 'unknown://', $descriptorspec, $pipes, '/tmp', null);
if (is_resource($process)) {
// $pipes now looks like this:
// 0 => writeable handle connected to child stdin
// 1 => readable handle connected to child stdout
// 2 => readable handle connected to child stderr
fwrite($pipes[0], $ntriples);
fclose($pipes[0]);
$output = stream_get_contents($pipes[1]);
fclose($pipes[1]);
$error = stream_get_contents($pipes[2]);
fclose($pipes[2]);
// It is important that you close any pipes before calling
// proc_close in order to avoid a deadlock
$returnValue = proc_close($process);
if ($returnValue) {
throw new EasyRdf_Exception("Failed to convert RDF: " . $error);
}
} else {
throw new EasyRdf_Exception("Failed to execute rapper command.");
}
return $output;
}
/**
* Serialise an EasyRdf_Graph to the RDF format of choice.
*
* @param object EasyRdf_Graph $graph An EasyRdf_Graph object.
* @param string $format The name of the format to convert to.
* @return string The RDF in the new desired format.
*/
public function serialise($graph, $format)
{
parent::checkSerialiseParams($graph, $format);
$ntriples = parent::serialise($graph, 'ntriples');
// Hack to produce more concise RDF/XML
if ($format == 'rdfxml') {
$format = 'rdfxml-abbrev';
}
return EasyRdf_Utils::execCommandPipe($this->_rapperCmd, array('--quiet', '--input', 'ntriples', '--output', $format, '-', 'unknown://'), $ntriples);
}
