PageHTMLHandler.php

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<?php
 
namespace MediaWiki\Rest\Handler;
 
use Config;
use ConfigException;
use Exception;
use GuzzleHttp\Psr7\Uri;
use LogicException;
use MediaWiki\Linker\LinkTarget;
use MediaWiki\Permissions\PermissionManager;
use MediaWiki\Rest\LocalizedHttpException;
use MediaWiki\Rest\Response;
use MediaWiki\Rest\StringStream;
use MediaWiki\Revision\RevisionLookup;
use RestbaseVirtualRESTService;
use TitleFormatter;
use UIDGenerator;
use VirtualRESTServiceClient;
use WebRequest;
use Wikimedia\Message\MessageValue;
 
class PageHTMLHandler extends LatestPageContentHandler {
    private const MAX_AGE_200 = 5;
 
    private $restClient;
 
    private $htmlResponse;
 
    public function __construct(
        Config $config,
        PermissionManager $permissionManager,
        RevisionLookup $revisionLookup,
        TitleFormatter $titleFormatter,
        VirtualRESTServiceClient $virtualRESTServiceClient
    ) {
        parent::__construct( $config, $permissionManager, $revisionLookup, $titleFormatter );
 
        $this->restClient = $virtualRESTServiceClient;
    }
 
    private function fetchHtmlFromRESTBase( LinkTarget $title ): array {
        if ( $this->htmlResponse !== null ) {
            return $this->htmlResponse;
        }
 
        list( , $service ) = $this->restClient->getMountAndService( '/restbase/ ' );
        if ( !$service ) {
            try {
                $restConfig = $this->config->get( 'VirtualRestConfig' );
                if ( !isset( $restConfig['modules']['restbase'] ) ) {
                    throw new ConfigException(
                        __CLASS__ . " requires restbase module configured for VirtualRestConfig"
                    );
                }
                $this->restClient->mount( '/restbase/',
                    new RestbaseVirtualRESTService( $restConfig['modules']['restbase'] ) );
            } catch ( Exception $e ) {
                // This would usually be config exception, but let's fail on any exception
                throw new LocalizedHttpException( MessageValue::new( 'rest-html-backend-error' ), 500 );
            }
        }
 
        $this->htmlResponse = $this->restClient->run( [
            'method' => 'GET',
            'url' => '/restbase/local/v1/page/html/' .
                urlencode( $this->titleFormatter->getPrefixedDBkey( $title ) ) .
                '?redirect=false'
        ] );
        return $this->htmlResponse;
    }
 
    private function fetch200HtmlFromRESTBase( LinkTarget $title ): array {
        $restbaseResp = $this->fetchHtmlFromRESTBase( $title );
        if ( $restbaseResp['code'] !== 200 ) {
            throw new LocalizedHttpException(
                MessageValue::new( 'rest-html-backend-error' ),
                $restbaseResp['code']
            );
        }
        return $restbaseResp;
    }
 
    private function constructHtmlUrl(): string {
        $wr = new WebRequest();
        $urlParts = wfParseUrl( $wr->getFullRequestURL() );
        $currentPathParts = explode( '/', $urlParts['path'] );
        $currentPathParts[ count( $currentPathParts ) - 1 ] = 'html';
        $urlParts['path'] = implode( '/', $currentPathParts );
        return Uri::fromParts( $urlParts );
    }
 
    public function run( string $title ): Response {
        $titleObj = $this->getTitle();
        if ( !$titleObj || !$titleObj->getArticleID() ) {
            throw new LocalizedHttpException(
                MessageValue::new( 'rest-nonexistent-title' )->plaintextParams( $title ),
                404
            );
        }
 
        if ( !$this->isAccessible( $titleObj ) ) {
            throw new LocalizedHttpException(
                MessageValue::new( 'rest-permission-denied-title' )->plaintextParams( $title ),
                403
            );
        }
 
        $revision = $this->getLatestRevision();
        if ( !$revision ) {
            throw new LocalizedHttpException(
                MessageValue::new( 'rest-no-revision' )->plaintextParams( $title ),
                404
            );
        }
 
        $htmlType = $this->getHtmlType();
        switch ( $htmlType ) {
            case 'bare':
                $body = $this->constructMetadata( $titleObj, $revision );
                $body['html_url'] = $this->constructHtmlUrl();
                $response = $this->getResponseFactory()->createJson( $body );
                break;
            case 'html':
                $restbaseResp = $this->fetch200HtmlFromRESTBase( $titleObj );
                $response = $this->getResponseFactory()->create();
                $response->setHeader( 'Content-Type', $restbaseResp[ 'headers' ][ 'content-type' ] );
                $response->setBody( new StringStream( $restbaseResp[ 'body' ] ) );
                break;
            case 'with_html':
                $restbaseResp = $this->fetch200HtmlFromRESTBase( $titleObj );
                $body = $this->constructMetadata( $titleObj, $revision );
                $body['html'] = $restbaseResp['body'];
                $response = $this->getResponseFactory()->createJson( $body );
                break;
            default:
                throw new LogicException( "Unknown HTML type $htmlType" );
        }
 
        $response->setHeader( 'Cache-Control', 'max-age=' . self::MAX_AGE_200 );
        return $response;
    }
 
    protected function getETag(): ?string {
        $title = $this->getTitle();
        if ( !$title || !$title->getArticleID() || !$this->isAccessible( $title ) ) {
            return null;
        }
        if ( $this->getHtmlType() === 'bare' ) {
            return '"' . $this->getLatestRevision()->getId() . '"';
        }
 
        $restbaseRes = $this->fetch200HtmlFromRESTBase( $title );
        return $restbaseRes['headers']['etag'] ?? null;
    }
 
    protected function getLastModified(): ?string {
        $title = $this->getTitle();
        if ( !$title || !$title->getArticleID() || !$this->isAccessible( $title ) ) {
            return null;
        }
 
        if ( $this->getHtmlType() === 'bare' ) {
            return $this->getLatestRevision()->getTimestamp();
        }
 
        $restbaseRes = $this->fetch200HtmlFromRESTBase( $title );
        $restbaseEtag = $restbaseRes['headers']['etag'] ?? null;
        if ( !$restbaseEtag ) {
            return null;
        }
 
        $etagComponents = [];
        if ( !preg_match( '/^(?:W\/)?"?[^"\/]+(?:\/([^"\/]+))"?$/',
            $restbaseEtag, $etagComponents )
        ) {
            return null;
        }
 
        return UIDGenerator::getTimestampFromUUIDv1( $etagComponents[1] ) ?: null;
    }
 
    private function getHtmlType(): string {
        return $this->getConfig()['format'];
    }
}