ContactCategory.php

<?php

namespace Drupal\contact\Plugin\migrate\source;

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

/**
 * Drupal 6/7 contact category source from database.
 *
 * For available configuration keys, refer to the parent classes.
 *
 * @see \Drupal\migrate\Plugin\migrate\source\SqlBase
 * @see \Drupal\migrate\Plugin\migrate\source\SourcePluginBase
 *
 * @MigrateSource(
 *   id = "contact_category",
 *   source_module = "contact"
 * )
 */
class ContactCategory extends DrupalSqlBase {
    
    /**
     * {@inheritdoc}
     */
    public function query() {
        $query = $this->select('contact', 'c')
            ->fields('c', [
            'cid',
            'category',
            'recipients',
            'reply',
            'weight',
            'selected',
        ]);
        $query->orderBy('c.cid');
        return $query;
    }
    
    /**
     * {@inheritdoc}
     */
    public function prepareRow(Row $row) {
        $row->setSourceProperty('recipients', explode(',', $row->getSourceProperty('recipients')));
        return parent::prepareRow($row);
    }
    
    /**
     * {@inheritdoc}
     */
    public function fields() {
        return [
            'cid' => $this->t('Primary Key: Unique category ID.'),
            'category' => $this->t('Category name.'),
            'recipients' => $this->t('Comma-separated list of recipient email addresses.'),
            'reply' => $this->t('Text of the auto-reply message.'),
            'weight' => $this->t("The category's weight."),
            'selected' => $this->t('Flag to indicate whether or not category is selected by default. (1 = Yes, 0 = No)'),
        ];
    }
    
    /**
     * {@inheritdoc}
     */
    public function getIds() {
        $ids['cid']['type'] = 'integer';
        return $ids;
    }

}