dumpCategoriesAsRdf.php

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<?php
use Wikimedia\Purtle\RdfWriter;
use Wikimedia\Purtle\RdfWriterFactory;
use Wikimedia\Rdbms\IDatabase;
 
require_once __DIR__ . '/Maintenance.php';
 
class DumpCategoriesAsRdf extends Maintenance {
    private $rdfWriter;
    private $categoriesRdf;
 
    public function __construct() {
        parent::__construct();
 
        $this->addDescription( "Generate RDF dump of categories in a wiki." );
 
        $this->setBatchSize( 200 );
        $this->addOption( 'output', "Output file (default is stdout). Will be overwritten.",
            false, true );
        $this->addOption( 'format', "Set the dump format.", false, true );
    }
 
    public function getCategoryIterator( IDatabase $dbr ) {
        $it = new BatchRowIterator(
            $dbr,
            'page',
            [ 'page_title' ],
            $this->mBatchSize
        );
        $it->addConditions( [
            'page_namespace' => NS_CATEGORY,
        ] );
        $it->setFetchColumns( [ 'page_title', 'page_id' ] );
        return $it;
    }
 
    public function getCategoryLinksIterator( IDatabase $dbr, array $ids ) {
        $it = new BatchRowIterator(
            $dbr,
            'categorylinks',
            [ 'cl_from', 'cl_to' ],
            $this->mBatchSize
        );
        $it->addConditions( [
            'cl_type' => 'subcat',
            'cl_from' => $ids
        ] );
        $it->setFetchColumns( [ 'cl_from', 'cl_to' ] );
        return new RecursiveIteratorIterator( $it );
    }
 
    public function addDumpHeader( $timestamp ) {
        global $wgRightsUrl;
        $licenseUrl = $wgRightsUrl;
        if ( substr( $licenseUrl, 0, 2 ) == '//' ) {
            $licenseUrl = 'https:' . $licenseUrl;
        }
        $this->rdfWriter->about( wfExpandUrl( '/categoriesDump', PROTO_CANONICAL ) )
            ->a( 'schema', 'Dataset' )
            ->a( 'owl', 'Ontology' )
            ->say( 'cc', 'license' )->is( $licenseUrl )
            ->say( 'schema', 'softwareVersion' )->value( CategoriesRdf::FORMAT_VERSION )
            ->say( 'schema', 'dateModified' )
                ->value( wfTimestamp( TS_ISO_8601, $timestamp ), 'xsd', 'dateTime' )
            ->say( 'schema', 'isPartOf' )->is( wfExpandUrl( '/', PROTO_CANONICAL ) )
            ->say( 'owl', 'imports' )->is( CategoriesRdf::OWL_URL );
    }
 
    public function execute() {
        $outFile = $this->getOption( 'output', 'php://stdout' );
 
        if ( $outFile === '-' ) {
            $outFile = 'php://stdout';
        }
 
        $output = fopen( $outFile, 'w' );
        $this->rdfWriter = $this->createRdfWriter( $this->getOption( 'format', 'ttl' ) );
        $this->categoriesRdf = new CategoriesRdf( $this->rdfWriter );
 
        $this->categoriesRdf->setupPrefixes();
        $this->rdfWriter->start();
 
        $this->addDumpHeader( time() );
        fwrite( $output, $this->rdfWriter->drain() );
 
        $dbr = $this->getDB( DB_REPLICA, [ 'vslow' ] );
 
        foreach ( $this->getCategoryIterator( $dbr ) as $batch ) {
            $pages = [];
            foreach ( $batch as $row ) {
                $this->categoriesRdf->writeCategoryData( $row->page_title );
                $pages[$row->page_id] = $row->page_title;
            }
 
            foreach ( $this->getCategoryLinksIterator( $dbr, array_keys( $pages ) ) as $row ) {
                $this->categoriesRdf->writeCategoryLinkData( $pages[$row->cl_from], $row->cl_to );
            }
            fwrite( $output, $this->rdfWriter->drain() );
        }
        fflush( $output );
        if ( $outFile !== '-' ) {
            fclose( $output );
        }
    }
 
    private function createRdfWriter( $format ) {
        $factory = new RdfWriterFactory();
        return $factory->getWriter( $factory->getFormatName( $format ) );
    }
}
 
$maintClass = "DumpCategoriesAsRdf";
require_once RUN_MAINTENANCE_IF_MAIN;