VariableMultiRow.php

<?php

namespace Drupal\migrate_drupal\Plugin\migrate\source;

use Drupal\migrate\Row;

/**
 * Multiple variables source from database.
 *
 * Unlike the variable source plugin, this one returns one row per
 * variable.
 *
 * @MigrateSource(
 *   id = "variable_multirow",
 *   source_module = "system",
 * )
 */
class VariableMultiRow extends DrupalSqlBase {
    
    /**
     * {@inheritdoc}
     */
    public function query() {
        return $this->select('variable', 'v')
            ->fields('v', [
            'name',
            'value',
        ])
            ->condition('name', (array) $this->configuration['variables'], 'IN');
    }
    
    /**
     * {@inheritdoc}
     */
    public function fields() {
        return [
            'name' => $this->t('Name'),
            'value' => $this->t('Value'),
        ];
    }
    
    /**
     * {@inheritdoc}
     */
    public function prepareRow(Row $row) {
        if ($value = $row->getSourceProperty('value')) {
            $row->setSourceProperty('value', unserialize($value));
        }
        return parent::prepareRow($row);
    }
    
    /**
     * {@inheritdoc}
     */
    public function getIds() {
        $ids['name']['type'] = 'string';
        return $ids;
    }

}