FieldListOptions.php

<?php

namespace Drupal\rules\TypedData\Options;

use Drupal\Core\DependencyInjection\ContainerInjectionInterface;
use Drupal\Core\Entity\EntityFieldManagerInterface;
use Drupal\Core\Session\AccountInterface;
use Symfony\Component\DependencyInjection\ContainerInterface;

/**
 * Options provider to return all fields in the system.
 */
class FieldListOptions extends OptionsProviderBase implements ContainerInjectionInterface {
    
    /**
     * The entity field manager service.
     *
     * @var \Drupal\Core\Entity\EntityFieldManagerInterface
     */
    protected $entityFieldManager;
    
    /**
     * Constructs a FieldListOptions object.
     *
     * @param \Drupal\Core\Entity\EntityFieldManagerInterface $entity_field_manager
     *   The entity field manager service.
     */
    public function __construct(EntityFieldManagerInterface $entity_field_manager) {
        $this->entityFieldManager = $entity_field_manager;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container) {
        return new static($container->get('entity_field.manager'));
    }
    
    /**
     * {@inheritdoc}
     */
    public function getPossibleOptions(AccountInterface $account = NULL) {
        $options = [];
        // Load all the fields in the system.
        $fields = $this->entityFieldManager
            ->getFieldMap();
        // Add each field to our options array.
        foreach ($fields as $entity_fields) {
            foreach ($entity_fields as $field_name => $field) {
                $options[$field_name] = $field_name . ' (' . $field['type'] . ')';
            }
        }
        // Sort the result by value for ease of locating and selecting.
        asort($options);
        return $options;
    }

}