wikimedia/mediawiki-extensions-Wikibase

<?php

declare( strict_types = 1 );

namespace Wikibase\Repo\Actions;

use Article;
use MediaWiki\Html\Html;
use MediaWiki\Output\OutputPage;
use MediaWiki\SpecialPage\SpecialPage;
use ViewAction;
use Wikibase\Repo\WikibaseRepo;

/**
 * Handles the view action for Wikibase entities.
 *
 * @license GPL-2.0-or-later
 * @author Jeroen De Dauw < jeroendedauw@gmail.com >
 * @author Daniel Kinzler < daniel.kinzler@wikimedia.de >
 */
class ViewEntityAction extends ViewAction {

    /**
     * Handler for the BeforeDisplayNoArticleText called by Article.
     * We implement this solely to replace the standard message that
     * is shown when an entity does not exists.
     *
     * @param Article $article
     * @return bool
     */
    public static function onBeforeDisplayNoArticleText( Article $article ) {
        $namespaceLookup = WikibaseRepo::getLocalEntityNamespaceLookup();
        $contentFactory = WikibaseRepo::getEntityContentFactory();

        $ns = $article->getTitle()->getNamespace();
        $oldid = $article->getOldID();

        if ( !$oldid && $namespaceLookup->isEntityNamespace( $ns ) ) {
            $entityType = $namespaceLookup->getEntityType( $ns );
            $handler = $contentFactory->getContentHandlerForType( $entityType );
            $handler->showMissingEntity( $article->getTitle(), $article->getContext() );

            return false;
        }

        return true;
    }

    /**
     * @see ViewAction::show
     *
     * Parent is doing $this->checkCanExecute( $this->getUser() )
     */
    public function show() {
        $this->showEntityPage();
    }

    /**
     * @return bool False for older revisions, or if this is for sure not a plain view (e.g. diff or
     *  print view).
     */
    private function isEditable() {
        return $this->getArticle()->isCurrent()
            && !$this->isDiff()
            && !$this->getOutput()->isPrintable();
    }

    /**
     * @return bool
     */
    private function isDiff() {
        return $this->getRequest()->getCheck( 'diff' );
    }

    private function showEntityPage() {
        $outputPage = $this->getOutput();

        // NOTE: page-wide property, independent of user permissions
        $outputPage->addJsConfigVars( 'wbIsEditView', $this->isEditable() );
        $this->getArticle()->view();

        $this->addLinkHeaders( $outputPage );
        $this->overridePageMetaTags( $outputPage );
    }

    /**
     * Create an alternate link header for the given URI and MIME
     * type, with no extra information.
     *
     * @param string $url the URL of the relation
     * @param string $type the MIME type for the link header entry
     *
     * @return string relation
     */
    private function constructLinkAlternateHeader( string $url, string $type ): string {
        return '<' . $url . '>; rel="alternate"; type="' . $type . '"';
    }

    /**
     * Add alternate links to the HTTP response.
     *
     * @param OutputPage $outputPage
     */
    private function addLinkHeaders( OutputPage $outputPage ) {
        if ( !$this->isEditable() ) {
            return;
        }
        $variables = $outputPage->getJsConfigVars();
        if ( !isset( $variables['wbEntityId'] ) ) {
            return;
        }
        $subPagePrefix = $variables['wbEntityId'] . '.';
        $entityDataFormatProvider = WikibaseRepo::getEntityDataFormatProvider();
        foreach ( $entityDataFormatProvider->getAllowedFormats() as $format ) {
            $ext = $entityDataFormatProvider->getExtension( $format );
            $mime = $entityDataFormatProvider->getMimeType( $format );
            if ( $ext === null || $mime === null ) {
                continue;
            }
            $entityDataTitle = SpecialPage::getTitleFor(
                'EntityData',
                $subPagePrefix . $ext
            );
            $linkAlternateHeader = $this->constructLinkAlternateHeader(
                $entityDataTitle->getCanonicalURL(),
                $mime
            );
            $this->getOutput()->addLinkHeader( $linkAlternateHeader );
        }
    }

    /**
     * This will be the label, if available, or else the entity id (e.g. 'Q42').
     * This is passed via parser output and output page to save overhead on view actions.
     *
     * @param OutputPage $outputPage
     */
    private function overridePageMetaTags( OutputPage $outputPage ) {
        $meta = $this->getOutput()->getProperty( 'wikibase-meta-tags' );

        if ( $this->isDiff() ) {
            if ( isset( $meta['title'] ) ) {
                $this->setDiffPageTitle( $outputPage, $meta['title'] );
            }

            // No description, social media tags, or any search engine optimization for diffs
            return;
        }

        if ( isset( $meta['title'] ) ) {
            $this->setHTMLTitle( $outputPage, $meta['title'] );
            $outputPage->addMeta( 'og:title', $meta['title'] );
        }

        if ( isset( $meta['description'] ) ) {
            $outputPage->addMeta( 'description', $meta['description'] );
            $outputPage->addMeta( 'og:description', $meta['description'] );

            if ( isset( $meta['title'] ) ) {
                $outputPage->addMeta( 'og:type', 'summary' );
            }
        }
    }

    /**
     * @param OutputPage $outputPage
     * @param string $titleText
     */
    private function setDiffPageTitle( OutputPage $outputPage, $titleText ) {
        $variables = $outputPage->getJsConfigVars();

        if ( !isset( $variables['wbEntityId'] ) ) {
            wfLogWarning( "'wbEntityId' has not been found." );
            $id = '';
        } else {
            $id = ' ' . Html::element(
                'span',
                [ 'class' => 'wikibase-title-id' ],
                $this->msg( 'parentheses' )->plaintextParams( $variables['wbEntityId'] )->text()
            );
        }

        $outputPage->setPageTitleMsg(
            $this->msg(
                'difference-title'
                // This should be something like the following,
                // $labelLang->getDirMark() . $titleText . $wgLang->getDirMark()
                // or should set the attribute of the h1 to correct direction.
                // Still note that the direction is "auto" so guessing should
                // give the right direction in most cases.
            )->rawParams( htmlspecialchars( $titleText ) . $id )
        );
    }

    /**
     * @param OutputPage $outputPage
     * @param string $titleText
     */
    private function setHTMLTitle( OutputPage $outputPage, $titleText ) {
        $outputPage->setHTMLTitle( $this->msg( 'pagetitle' )->plaintextParams( $titleText ) );
    }

    /**
     * @see Action::getDescription
     *
     * @return string Empty.
     */
    protected function getDescription() {
        return '';
    }

    /**
     * @see Action::requiresUnblock
     *
     * @return bool Always false, but overridden by some subclasses.
     */
    public function requiresUnblock() {
        return false;
    }

    /**
     * @see Action::requiresWrite
     *
     * @return bool Always false, but overridden by some subclasses.
     */
    public function requiresWrite() {
        return false;
    }

}