PathAliasExists.php

<?php

namespace Drupal\rules\Plugin\Condition;

use Drupal\Core\Language\LanguageInterface;
use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
use Drupal\path_alias\AliasManagerInterface;
use Drupal\rules\Core\RulesConditionBase;
use Symfony\Component\DependencyInjection\ContainerInterface;

/**
 * Provides a 'Path alias exists' condition.
 *
 * @todo Add access callback information from Drupal 7.
 *
 * @Condition(
 *   id = "rules_path_alias_exists",
 *   label = @Translation("Path alias exists"),
 *   category = @Translation("Path"),
 *   provider = "path_alias",
 *   context_definitions = {
 *     "alias" = @ContextDefinition("string",
 *       label = @Translation("Path alias"),
 *       description = @Translation("Specify the path alias to check for. For example, '/about' for an about page.")
 *     ),
 *     "language" = @ContextDefinition("language",
 *       label = @Translation("Language"),
 *       description = @Translation("If specified, the language for which the URL alias applies."),
 *       options_provider = "\Drupal\rules\TypedData\Options\LanguageOptions",
 *       default_value = NULL,
 *       required = FALSE
 *     ),
 *   }
 * )
 */
class PathAliasExists extends RulesConditionBase implements ContainerFactoryPluginInterface {
    
    /**
     * The alias manager service.
     *
     * @var \Drupal\path_alias\AliasManagerInterface
     */
    protected $aliasManager;
    
    /**
     * Constructs a PathAliasExists 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\path_alias\AliasManagerInterface $alias_manager
     *   The alias manager service.
     */
    public function __construct(array $configuration, $plugin_id, $plugin_definition, AliasManagerInterface $alias_manager) {
        parent::__construct($configuration, $plugin_id, $plugin_definition);
        $this->aliasManager = $alias_manager;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
        return new static($configuration, $plugin_id, $plugin_definition, $container->get('path_alias.manager'));
    }
    
    /**
     * Check if a path alias exists.
     *
     * @param string $alias
     *   The alias to see if exists.
     * @param \Drupal\Core\Language\LanguageInterface|null $language
     *   The language to use.
     *
     * @return bool
     *   TRUE if the system path does not match the given alias (ie: the alias
     *   exists).
     */
    protected function doEvaluate($alias, LanguageInterface $language = NULL) {
        $langcode = is_null($language) ? NULL : $language->getId();
        $path = $this->aliasManager
            ->getPathByAlias($alias, $langcode);
        // getPathByAlias() returns the alias if there is no path.
        return $path != $alias;
    }

}