NodeRevision.php

<?php

namespace Drupal\node\Plugin\migrate\source\d7;


/**
 * Drupal 7 node revision source from database.
 *
 * @MigrateSource(
 *   id = "d7_node_revision",
 *   source_module = "node"
 * )
 */
class NodeRevision extends Node {
    
    /**
     * The join options between the node and the node_revisions_table.
     */
    const JOIN = 'n.nid = nr.nid AND n.vid <> nr.vid';
    
    /**
     * {@inheritdoc}
     */
    public function fields() {
        // Use all the node fields plus the vid that identifies the version.
        return parent::fields() + [
            'vid' => t('The primary identifier for this version.'),
            'log' => $this->t('Revision Log message'),
            'timestamp' => $this->t('Revision timestamp'),
        ];
    }
    
    /**
     * {@inheritdoc}
     */
    public function getIds() {
        $ids['vid']['type'] = 'integer';
        $ids['vid']['alias'] = 'nr';
        return $ids;
    }

}