--- /dev/null
+<?php
+
+namespace Drupal\migrate_drupal\Plugin\migrate\source\d7;
+
+use Drupal\migrate_drupal\Plugin\migrate\source\DrupalSqlBase;
+
+/**
+ * Base class for D7 source plugins which need to collect field values from
+ * the Field API.
+ */
+abstract class FieldableEntity extends DrupalSqlBase {
+
+ /**
+ * Returns all non-deleted field instances attached to a specific entity type.
+ *
+ * @param string $entity_type
+ * The entity type ID.
+ * @param string|null $bundle
+ * (optional) The bundle.
+ *
+ * @return array[]
+ * The field instances, keyed by field name.
+ */
+ protected function getFields($entity_type, $bundle = NULL) {
+ return $this->select('field_config_instance', 'fci')
+ ->fields('fci')
+ ->condition('entity_type', $entity_type)
+ ->condition('bundle', isset($bundle) ? $bundle : $entity_type)
+ ->condition('deleted', 0)
+ ->execute()
+ ->fetchAllAssoc('field_name');
+ }
+
+ /**
+ * Retrieves field values for a single field of a single entity.
+ *
+ * @param string $entity_type
+ * The entity type.
+ * @param string $field
+ * The field name.
+ * @param int $entity_id
+ * The entity ID.
+ * @param int|null $revision_id
+ * (optional) The entity revision ID.
+ *
+ * @return array
+ * The raw field values, keyed by delta.
+ *
+ * @todo Support multilingual field values.
+ */
+ protected function getFieldValues($entity_type, $field, $entity_id, $revision_id = NULL) {
+ $table = (isset($revision_id) ? 'field_revision_' : 'field_data_') . $field;
+ $query = $this->select($table, 't')
+ ->fields('t')
+ ->condition('entity_type', $entity_type)
+ ->condition('entity_id', $entity_id)
+ ->condition('deleted', 0);
+ if (isset($revision_id)) {
+ $query->condition('revision_id', $revision_id);
+ }
+ $values = [];
+ foreach ($query->execute() as $row) {
+ foreach ($row as $key => $value) {
+ $delta = $row['delta'];
+ if (strpos($key, $field) === 0) {
+ $column = substr($key, strlen($field) + 1);
+ $values[$delta][$column] = $value;
+ }
+ }
+ }
+ return $values;
+ }
+
+}