wikimedia/mediawiki-extensions-Wikibase

<?php

namespace Wikibase\Lib\Formatters;

use MediaWiki\Html\Html;
use Wikibase\DataModel\Snak\PropertyValueSnak;
use Wikibase\DataModel\Snak\Snak;
use Wikibase\Lib\SnakUrlExpander;
use Wikimedia\Assert\Assert;
use Wikimedia\Assert\ParameterTypeException;

/**
 * A formatter for PropertyValueSnaks that contain a StringValue that is interpreted
 * as an external identifier. The identifier is rendered as an HTML link to some resource about
 * the identifier. The link is created based on a URL pattern associated with the snak's property id
 * via a SnakUrlExpander.
 *
 * @license GPL-2.0-or-later
 * @author Daniel Kinzler
 */
class HtmlExternalIdentifierFormatter implements SnakFormatter {

    /**
     * @var SnakUrlExpander
     */
    private $urlExpander;

    public function __construct( SnakUrlExpander $urlExpander ) {
        $this->urlExpander = $urlExpander;
    }

    /**
     * @see SnakFormatter::format
     *
     * Formats the given Snak's value as a HTML link.
     * The URL of that link is determined using a SnakUrlExpander.
     * If the snak could not be expanded into a URL, the identifier is returned as simple text.
     *
     * @param Snak $snak
     *
     * @throws ParameterTypeException if $snak is not a PropertyValueSnak, or if $snak->getDataValue()
     * does not return a StringValue.
     * @return string HTML
     */
    public function formatSnak( Snak $snak ) {
        Assert::parameterType( PropertyValueSnak::class, $snak, '$snak' );
        /** @var PropertyValueSnak $snak */
        '@phan-var PropertyValueSnak $snak';

        $id = $snak->getDataValue()->getValue();
        $url = $this->urlExpander->expandUrl( $snak );
        $attr = [ 'class' => 'wb-external-id' ];

        if ( $url === null ) {
            return Html::element( 'span', $attr, $id );
        } else {
            $attr['href'] = $url;
            // TODO: configure from options; see also HtmlUrlFormatter
            $attr['class'] .= ' external';
            $attr['rel'] = 'nofollow';
            return Html::element( 'a', $attr, $id );
        }
    }

    /**
     * @see SnakFormatter::getFormat
     *
     * @return string SnakFormatter::FORMAT_HTML
     */
    public function getFormat() {
        return SnakFormatter::FORMAT_HTML;
    }

}