class LinkUri

class LinkUri extends ProcessPluginBase implements ContainerFactoryPluginInterface {
    
    /**
     * The entity type manager, used to fetch entity link templates.
     *
     * @var \Drupal\Core\Entity\EntityTypeManagerInterface
     */
    protected $entityTypeManager;
    
    /**
     * Constructs a LinkUri object.
     *
     * @param array $configuration
     *   A configuration array containing information about the plugin instance.
     * @param string $plugin_id
     *   The plugin_id for the plugin instance.
     * @param mixed $plugin_definition
     *   The plugin implementation definition.
     * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
     *   The entity type manager, used to fetch entity link templates.
     */
    public function __construct(array $configuration, $plugin_id, $plugin_definition, EntityTypeManagerInterface $entity_type_manager) {
        $configuration += [
            'validate_route' => TRUE,
        ];
        parent::__construct($configuration, $plugin_id, $plugin_definition);
        $this->entityTypeManager = $entity_type_manager;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
        return new static($configuration, $plugin_id, $plugin_definition, $container->get('entity_type.manager'));
    }
    
    /**
     * {@inheritdoc}
     */
    public function transform($value, MigrateExecutableInterface $migrate_executable, Row $row, $destination_property) {
        $path = ltrim($value, '/');
        if (parse_url($path, PHP_URL_SCHEME) === NULL) {
            if ($path == '<front>') {
                $path = '';
            }
            elseif ($path == '<nolink>') {
                return 'route:<nolink>';
            }
            $path = 'internal:/' . $path;
            // Convert entity URIs to the entity scheme, if the path matches a route
            // of the form "entity.$entity_type_id.canonical".
            // @see \Drupal\Core\Url::fromEntityUri()
            $url = Url::fromUri($path);
            if ($url->isRouted()) {
                $route_name = $url->getRouteName();
                foreach (array_keys($this->entityTypeManager
                    ->getDefinitions()) as $entity_type_id) {
                    if ($route_name == "entity.{$entity_type_id}.canonical" && isset($url->getRouteParameters()[$entity_type_id])) {
                        return "entity:{$entity_type_id}/" . $url->getRouteParameters()[$entity_type_id];
                    }
                }
            }
            else {
                // If the URL is not routed, we might want to get something back to do
                // other processing. If this is the case, the "validate_route"
                // configuration option can be set to FALSE to return the URI.
                if (!$this->configuration['validate_route']) {
                    return $url->getUri();
                }
                else {
                    throw new MigrateException(sprintf('The path "%s" failed validation.', $path));
                }
            }
        }
        return $path;
    }

}