relation method

@override Future<PaginatedRecords> relation(String resourceKey, Object id, RelationDescriptor relation, { int page = 1, String? search, String? sort, String? direction, })

One relation manager's rows for record id — the same envelope list parses, against the sibling URL RelationController serves. Unlike list, the child rows' own key comes from relation itself (relation.recordKey), not from this resource's schema: the related model is routinely a different one, with a different route key.

Implementation

@override
Future<PaginatedRecords> relation(
  String resourceKey,
  Object id,
  RelationDescriptor relation, {
  int page = 1,
  String? search,
  String? sort,
  String? direction,
}) async {
  // The same omission rule as [list]: an unknown sort key is a 422 on the
  // relation endpoint too, and a blank search would be a search for nothing.
  final response = await _transport.get(
    '$prefix/$resourceKey/$id/relations/${relation.key}',
    query: {
      'page': '$page',
      if (search != null && search.trim().isNotEmpty) 'search': search,
      if (sort != null && sort.trim().isNotEmpty) 'sort': sort,
      if (direction != null && direction.trim().isNotEmpty)
        'direction': direction,
    },
  );

  final rows = response['data'];
  final meta = response['meta'];

  return PaginatedRecords(
    records: [
      if (rows is List)
        for (final row in rows)
          if (row is Map<String, dynamic>)
            ResourceRecord.fromJson(row, relation.recordKey),
    ],
    meta: PageMeta.fromJson(meta is Map<String, dynamic> ? meta : const {}),
  );
}