/**
* The main code goes here
*/
function execute($par)
{
global $wgOut;
try {
# Set HTML headers sent to the browser
$this->setHeaders();
# The main code
$requestData = $this->getRequestData();
if ($requestData->hasWriteAccess && $requestData->action === 'import') {
$importInfo = $this->importData($requestData);
$triples = $importInfo['triples'];
if ($triples) {
$rdfImporter = new RDFIORDFImporter();
$wgOut->addHTML($this->getHTMLForm($requestData));
$wgOut->addHTML($rdfImporter->showImportedTriples($triples));
if ($requestData->externalRdfUrl) {
$rdfImporter->addDataSource($requestData->externalRdfUrl, 'RDF');
}
} else {
if (!$triples) {
throw new RDFIOException("No new triples to import");
}
}
} else {
if (!$requestData->hasWriteAccess) {
throw new RDFIOException("User does not have write access");
} else {
$wgOut->addHTML($this->getHTMLForm($requestData));
$wgOut->addHTML('<div id=sources style="display:none">');
$wgOut->addWikiText('{{#ask: [[Category:RDFIO Data Source]] [[RDFIO Import Type::RDF]] |format=list }}');
$wgOut->addHTML('</div>');
}
}
} catch (MWException $e) {
RDFIOUtils::showErrorMessage('Error!', $e->getMessage());
}
}
protected function import($limit = 10, $offset = 0)
{
global $wgOut, $wgRequest;
//$rdfioUtils = new RDFIOUtils();
$externalSparqlUrl = $wgRequest->getText('extsparqlurl');
if ($externalSparqlUrl === '') {
throw new RDFIOException('Empty SPARQL Url provided!');
} else {
if (!RDFIOUtils::isURI($externalSparqlUrl)) {
throw new RDFIOException('Invalid SPARQL Url provided! (Must start with \'http://\' or \'https://\')');
}
}
$sparqlQuery = urlencode("SELECT DISTINCT * WHERE { ?s ?p ?o } OFFSET {$offset} LIMIT {$limit}");
$sparqlQueryUrl = $externalSparqlUrl . '/' . '?query=' . $sparqlQuery;
$sparqlResultXml = file_get_contents($sparqlQueryUrl);
$sparqlResultXmlObj = simplexml_load_string($sparqlResultXml);
$importTriples = array();
if (is_object($sparqlResultXmlObj)) {
foreach ($sparqlResultXmlObj->results->children() as $result) {
$triple = array();
// $wgOut->addHTML( print_r($result, true) );
foreach ($result as $binding) {
if ($binding['name'] == 's') {
$s = (string) $binding->uri[0];
if ($s == '') {
throw new Exception('Could not extract subject from empty string (' . print_r($binding->uri, true) . '), in SPARQLImport');
}
$triple['s'] = $s;
$triple['s_type'] = $this->resourceType($triple['s']);
} else {
if ($binding['name'] == 'p') {
$p = (string) $binding->uri[0];
if ($p == '') {
throw new Exception('Could not extract predicate from empty string (' . print_r($binding->uri, true) . '), in SPARQLImport');
}
$triple['p'] = $p;
$triple['p_type'] = $this->resourceType($triple['p']);
} else {
if ($binding['name'] == 'o') {
$o = (string) $binding->uri[0];
if ($o == '') {
throw new Exception('Could not extract object from empty string (' . print_r($binding->uri, true) . '), in SPARQLImport');
}
$triple['o'] = $o;
$triple['o_type'] = $this->resourceType($triple['o']);
$triple['o_datatype'] = '';
}
}
}
}
$importTriples[] = $triple;
}
$rdfImporter = new RDFIORDFImporter();
$rdfImporter->importTriples($importTriples);
$wgOut->addHTML($rdfImporter->showImportedTriples($importTriples));
} else {
RDFIOUtils::formatErrorHTML("Error", "There was a problem importing from the endpoint. Are you sure that the given URL is a valid SPARQL endpoint?");
}
return $output = array('externalSparqlUrl' => $externalSparqlUrl);
}
