wikimedia/mediawiki-extensions-CirrusSearch

<?php

namespace CirrusSearch\Event;

use CirrusSearch\PageChangeTracker;
use MediaWiki\Config\Config;
use MediaWiki\Config\ConfigFactory;
use MediaWiki\Deferred\DeferredUpdates;
use MediaWiki\Extension\EventBus\EventBusFactory;
use MediaWiki\Extension\EventBus\StreamNameMapper;
use MediaWiki\Page\PageLookup;
use MediaWiki\Request\WebRequest;
use MediaWiki\Title\TitleFormatter;
use Wikimedia\UUID\GlobalIdGenerator;

/**
 * Hook handler responsible for bridging internal MW events to dedicated event streams.
 */
class EventBusBridge extends PageChangeTracker implements EventBridge {
    private EventBusFactory $eventBusFactory;
    private PageLookup $pageLookup;
    private PageRerenderSerializer $pageRerenderSerializer;

    /**
     * @param EventBusFactory $eventBusFactory
     * @param PageLookup $pageLookup
     * @param PageRerenderSerializer $pageRerenderSerializer
     */
    public function __construct(
        EventBusFactory $eventBusFactory,
        PageLookup $pageLookup,
        PageRerenderSerializer $pageRerenderSerializer,
        int $maxStateSize = 512
    ) {
        parent::__construct( $maxStateSize );
        $this->eventBusFactory = $eventBusFactory;
        $this->pageLookup = $pageLookup;
        $this->pageRerenderSerializer = $pageRerenderSerializer;
    }

    /**
     * @param ConfigFactory $configFactory
     * @param Config $mainConfig
     * @param GlobalIdGenerator $globalIdGenerator
     * @param TitleFormatter $titleFormatter
     * @param PageLookup $pageLookup
     * @param EventBusFactory|null $eventBusFactory
     * @return EventBridge
     */
    public static function factory(
        ConfigFactory $configFactory,
        Config $mainConfig,
        GlobalIdGenerator $globalIdGenerator,
        TitleFormatter $titleFormatter,
        PageLookup $pageLookup,
        EventBusFactory $eventBusFactory = null,
        StreamNameMapper $streamNameMapper = null
    ): EventBridge {
        $config = $configFactory->makeConfig( "CirrusSearch" );
        '@phan-var \CirrusSearch\SearchConfig $config';
        if ( $eventBusFactory !== null && $config->get( 'CirrusSearchUseEventBusBridge' ) ) {
            if ( $streamNameMapper === null ) {
                throw new \RuntimeException( 'EventBusFactory provided without StreamNameMapper' );
            }
            $pageRerenderSerializer = new PageRerenderSerializer( $mainConfig, $titleFormatter,
                $config, $globalIdGenerator, $streamNameMapper );
            return new self( $eventBusFactory, $pageLookup, $pageRerenderSerializer );
        }
        return new class() implements EventBridge {
            /**
             * @inheritDoc
             */
            public function onLinksUpdateComplete( $linksUpdate, $ticket ) {
            }
        };
    }

    /**
     * @inheritDoc
     */
    public function onLinksUpdateComplete( $linksUpdate, $ticket ) {
        DeferredUpdates::addCallableUpdate( function () use ( $linksUpdate ) {
            if ( $this->isPageChange( $linksUpdate->getPageId() ) ) {
                // Page changes are handled via the page-change stream
                return;
            }
            $page = $this->pageLookup->getPageById( $linksUpdate->getPageId() );
            if ( $page === null ) {
                // the page no longer exists
                return;
            }
            if ( $page->isRedirect() ) {
                // We are not really interested in redirects at this point
                // since we would ultimately refresh the target of this redirect we assume
                // that a LinksUpdate for the redirect does not imply that the target page has
                // to re-render as well.
                return;
            }
            $event = $this->pageRerenderSerializer->eventDataForPage( $page,
                PageRerenderSerializer::LINKS_UPDATE_REASON, WebRequest::getRequestId() );
            // Fire and forget, we do not check the return value, problems should be already logged by
            // EventBus
            $this->eventBusFactory
                ->getInstanceForStream( $event['meta']['stream'] )
                ->send( [ $event ] );
        } );
    }
}