Field.php

<?php

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

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

/**
 * Drupal 7 field source from database.
 *
 * @MigrateSource(
 *   id = "d7_field",
 *   source_module = "field_sql_storage"
 * )
 */
class Field extends DrupalSqlBase {
    
    /**
     * {@inheritdoc}
     */
    public function query() {
        $query = $this->select('field_config', 'fc')
            ->distinct()
            ->fields('fc')
            ->fields('fci', [
            'entity_type',
        ])
            ->condition('fc.active', 1)
            ->condition('fc.storage_active', 1)
            ->condition('fc.deleted', 0)
            ->condition('fci.deleted', 0);
        $query->join('field_config_instance', 'fci', 'fc.id = fci.field_id');
        // If the Drupal 7 Title module is enabled, we don't want to migrate the
        // fields it provides. The values of those fields will be migrated to the
        // base fields they were replacing.
        if ($this->moduleExists('title')) {
            $title_fields = [
                'title_field',
                'name_field',
                'description_field',
                'subject_field',
            ];
            $query->condition('fc.field_name', $title_fields, 'NOT IN');
        }
        return $query;
    }
    
    /**
     * {@inheritdoc}
     */
    public function fields() {
        return [
            'id' => $this->t('The field ID.'),
            'field_name' => $this->t('The field name.'),
            'type' => $this->t('The field type.'),
            'module' => $this->t('The module that implements the field type.'),
            'active' => $this->t('The field status.'),
            'storage_type' => $this->t('The field storage type.'),
            'storage_module' => $this->t('The module that implements the field storage type.'),
            'storage_active' => $this->t('The field storage status.'),
            'locked' => $this->t('Locked'),
            'data' => $this->t('The field data.'),
            'cardinality' => $this->t('Cardinality'),
            'translatable' => $this->t('Translatable'),
            'deleted' => $this->t('Deleted'),
            'instances' => $this->t('The field instances.'),
        ];
    }
    
    /**
     * {@inheritdoc}
     */
    public function prepareRow(Row $row, $keep = TRUE) {
        foreach (unserialize($row->getSourceProperty('data')) as $key => $value) {
            $row->setSourceProperty($key, $value);
        }
        $instances = $this->select('field_config_instance', 'fci')
            ->fields('fci')
            ->condition('field_name', $row->getSourceProperty('field_name'))
            ->condition('entity_type', $row->getSourceProperty('entity_type'))
            ->execute()
            ->fetchAll();
        $row->setSourceProperty('instances', $instances);
        return parent::prepareRow($row);
    }
    
    /**
     * {@inheritdoc}
     */
    public function getIds() {
        return [
            'field_name' => [
                'type' => 'string',
                'alias' => 'fc',
            ],
            'entity_type' => [
                'type' => 'string',
                'alias' => 'fci',
            ],
        ];
    }

}