TokenProcessor.php

<?php

namespace Drupal\rules\Plugin\RulesDataProcessor;

use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
use Drupal\Core\Plugin\PluginBase;
use Drupal\rules\Context\DataProcessorInterface;
use Drupal\rules\Context\ExecutionStateInterface;
use Drupal\typed_data\PlaceholderResolverInterface;
use Symfony\Component\DependencyInjection\ContainerInterface;

/**
 * A data processor for placeholder token replacements.
 *
 * @RulesDataProcessor(
 *   id = "rules_tokens",
 *   label = @Translation("Placeholder token replacements")
 * )
 */
class TokenProcessor extends PluginBase implements DataProcessorInterface, ContainerFactoryPluginInterface {
    
    /**
     * The placeholder resolver.
     *
     * @var \Drupal\typed_data\PlaceholderResolverInterface
     */
    protected $placeholderResolver;
    
    /**
     * Constructs a TokenProcessor 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\typed_data\PlaceholderResolverInterface $placeholder_resolver
     *   The placeholder resolver.
     */
    public function __construct(array $configuration, $plugin_id, $plugin_definition, PlaceholderResolverInterface $placeholder_resolver) {
        parent::__construct($configuration, $plugin_id, $plugin_definition);
        $this->placeholderResolver = $placeholder_resolver;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
        return new static($configuration, $plugin_id, $plugin_definition, $container->get('typed_data.placeholder_resolver'));
    }
    
    /**
     * {@inheritdoc}
     */
    public function process($value, ExecutionStateInterface $rules_state) {
        $data = [];
        $placeholders_by_data = $this->placeholderResolver
            ->scan($value);
        foreach ($placeholders_by_data as $variable_name => $placeholders) {
            // Note that accessing an unavailable variable will throw an evaluation
            // exception. That's exactly what needs to happen. Invalid tokens must
            // be detected when checking integrity. The Rule must not be executed
            // if the integrity check fails. Runtime is too late to handle
            // invalid tokens gracefully.
            $data[$variable_name] = $rules_state->getVariable($variable_name);
        }
        return $this->placeholderResolver
            ->replacePlaceHolders($value, $data);
    }

}