Action.php

<?php

namespace Drupal\system\Plugin\migrate\source;

use Drupal\migrate_drupal\Plugin\migrate\source\DrupalSqlBase;
use Drupal\migrate\Row;

/**
 * Drupal action source from database.
 *
 * @MigrateSource(
 *   id = "action",
 *   source_module = "system"
 * )
 */
class Action extends DrupalSqlBase {
    
    /**
     * {@inheritdoc}
     */
    public function query() {
        return $this->select('actions', 'a')
            ->fields('a');
    }
    
    /**
     * {@inheritdoc}
     */
    public function fields() {
        $fields = [
            'aid' => $this->t('Action ID'),
            'type' => $this->t('Module'),
            'callback' => $this->t('Callback function'),
            'parameters' => $this->t('Action configuration'),
        ];
        if ($this->getModuleSchemaVersion('system') >= 7000) {
            $fields['label'] = $this->t('Label of the action');
        }
        else {
            $fields['description'] = $this->t('Action description');
        }
        return $fields;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getIds() {
        $ids['aid']['type'] = 'string';
        return $ids;
    }
    
    /**
     * {@inheritdoc}
     */
    public function prepareRow(Row $row) {
        $aid = $row->getSourceProperty('aid');
        if (is_numeric($aid)) {
            if ($this->getModuleSchemaVersion('system') >= 7000) {
                $label = $row->getSourceProperty('label');
            }
            else {
                $label = $row->getSourceProperty('description');
            }
            $row->setSourceProperty('aid', $label);
        }
        return parent::prepareRow($row);
    }

}