Parse RDF/XML to RDF/PHP using the redland PHP extension

redland_parse.php

<?php

$URL = 'http://dbpedia.org/resource/London.rdf';
$DATA = file_get_contents('london.rdf');
$FORMAT = "rdfxml";


if (!extension_loaded('redland')) {
    throw new Exception("redland extension is not loaded");
}

$librdfWorld = librdf_php_get_world();


$start = microtime(true);

$librdfStorage = librdf_new_storage($librdfWorld, "memory", null, null);
if (!$librdfStorage) {
    throw new Exception(
        "Failed to create librdf_storage"
    );
}

$librdfModel = librdf_new_model($librdfWorld, $librdfStorage, null);
if (!$librdfModel) {
    throw new Exception(
        "Failed to create librdf_model"
    );
}

$librdfParser = librdf_new_parser($librdfWorld, $FORMAT, null, null);
if (!$librdfParser) {
    throw new Exception(
        "Failed to create librdf_parser of type: $FORMAT"
    );
}

$librdfSerializer = librdf_new_serializer($librdfWorld, 'json', null, null);
if (!$librdfSerializer) {
    throw new Exception(
        "Failed to create librdf_serializer of type: 'json'"
    );
}

$librdfUri = librdf_new_uri($librdfWorld, $URL);
if (!$librdfUri) {
    throw new Exception(
        "Failed to create librdf_uri from: $URL"
    );
}

$result = librdf_parser_parse_string_into_model($librdfParser, $DATA, $librdfUri, $librdfModel);
if ($result) {
    throw new Exception(
        "Failed to parse '$URL' into model: $result"
    );
}

$json = librdf_serializer_serialize_model_to_string($librdfSerializer, $librdfUri, $librdfModel);
$rdfphp = json_decode($json);

librdf_free_uri($librdfUri);
librdf_free_serializer($librdfSerializer);
librdf_free_parser($librdfParser);
librdf_free_model($librdfModel);
librdf_free_storage($librdfStorage);

$duration = microtime(true) - $start;
print "  Parse time: $duration seconds\n";

@njh, thank you for your reply. Does the redland extension work well on php-7?
It seems that many people use the EasyRdf package to process rdf file in php-7.