class AliasPathProcessor

class AliasPathProcessor implements InboundPathProcessorInterface, OutboundPathProcessorInterface {
    
    /**
     * An alias manager for looking up the system path.
     *
     * @var \Drupal\path_alias\AliasManagerInterface
     */
    protected $aliasManager;
    
    /**
     * Constructs a AliasPathProcessor object.
     *
     * @param \Drupal\path_alias\AliasManagerInterface $alias_manager
     *   An alias manager for looking up the system path.
     */
    public function __construct(AliasManagerInterface $alias_manager) {
        $this->aliasManager = $alias_manager;
    }
    
    /**
     * {@inheritdoc}
     */
    public function processInbound($path, Request $request) {
        $path = $this->aliasManager
            ->getPathByAlias($path);
        return $path;
    }
    
    /**
     * {@inheritdoc}
     */
    public function processOutbound($path, &$options = [], Request $request = NULL, BubbleableMetadata $bubbleable_metadata = NULL) {
        if (empty($options['alias'])) {
            $langcode = isset($options['language']) ? $options['language']->getId() : NULL;
            $path = $this->aliasManager
                ->getAliasByPath($path, $langcode);
            // Ensure the resulting path has at most one leading slash, to prevent it
            // becoming an external URL without a protocol like //example.com. This
            // is done in \Drupal\Core\Routing\UrlGenerator::generateFromRoute()
            // also, to protect against this problem in arbitrary path processors,
            // but it is duplicated here to protect any other URL generation code
            // that might call this method separately.
            if (strpos($path, '//') === 0) {
                $path = '/' . ltrim($path, '/');
            }
        }
        return $path;
    }

}