class PathAlias

class PathAlias extends ContentEntityBase implements PathAliasInterface {
  use EntityPublishedTrait;
  
  /**
   * {@inheritdoc}
   */
  public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
    $fields = parent::baseFieldDefinitions($entity_type);
    $fields['path'] = BaseFieldDefinition::create('string')->setLabel(new TranslatableMarkup('System path'))
      ->setDescription(new TranslatableMarkup('The path that this alias belongs to.'))
      ->setRequired(TRUE)
      ->setRevisionable(TRUE)
      ->addPropertyConstraints('value', [
      'Regex' => [
        'pattern' => '/^\\//i',
        'message' => new TranslatableMarkup('The source path has to start with a slash.'),
      ],
    ])
      ->addPropertyConstraints('value', [
      'ValidPath' => [],
    ]);
    $fields['alias'] = BaseFieldDefinition::create('string')->setLabel(new TranslatableMarkup('URL alias'))
      ->setDescription(new TranslatableMarkup('An alias used with this path.'))
      ->setRequired(TRUE)
      ->setRevisionable(TRUE)
      ->addPropertyConstraints('value', [
      'Regex' => [
        'pattern' => '/^\\//i',
        'message' => new TranslatableMarkup('The alias path has to start with a slash.'),
      ],
    ]);
    $fields['langcode']->setDefaultValue(LanguageInterface::LANGCODE_NOT_SPECIFIED);
    // Add the published field.
    $fields += static::publishedBaseFieldDefinitions($entity_type);
    $fields['status']->setTranslatable(FALSE);
    return $fields;
  }
  
  /**
   * {@inheritdoc}
   */
  public function preSave(EntityStorageInterface $storage) {
    parent::preSave($storage);
    // Trim the alias value of whitespace and slashes. Ensure to not trim the
    // slash on the left side.
    $alias = rtrim(trim($this->getAlias()), "\\/");
    $this->setAlias($alias);
  }
  
  /**
   * {@inheritdoc}
   */
  public function postSave(EntityStorageInterface $storage, $update = TRUE) {
    parent::postSave($storage, $update);
    $alias_manager = \Drupal::service('path_alias.manager');
    $alias_manager->cacheClear($this->getPath());
    if ($update) {
      $alias_manager->cacheClear($this->getOriginal()
        ->getPath());
    }
  }
  
  /**
   * {@inheritdoc}
   */
  public static function postDelete(EntityStorageInterface $storage, array $entities) {
    parent::postDelete($storage, $entities);
    $alias_manager = \Drupal::service('path_alias.manager');
    foreach ($entities as $entity) {
      $alias_manager->cacheClear($entity->getPath());
    }
  }
  
  /**
   * {@inheritdoc}
   */
  public function getPath() {
    return $this->get('path')->value;
  }
  
  /**
   * {@inheritdoc}
   */
  public function setPath($path) {
    $this->set('path', $path);
    return $this;
  }
  
  /**
   * {@inheritdoc}
   */
  public function getAlias() {
    return $this->get('alias')->value;
  }
  
  /**
   * {@inheritdoc}
   */
  public function setAlias($alias) {
    $this->set('alias', $alias);
    return $this;
  }
  
  /**
   * {@inheritdoc}
   */
  public function label() {
    return $this->getAlias();
  }
  
  /**
   * {@inheritdoc}
   */
  public function getCacheTagsToInvalidate() {
    return [
      'route_match',
    ];
  }

}