load method

Future<Map<String, Object?>?> load(String stateId)

Loads the record for stateId, from disk when persistent.

stateId is host-generated (cp-<12 hex>): anything else is refused BEFORE it reaches the filesystem, so a client-controlled id can never traverse out of dir via an absolute path or ../.

Implementation

Future<Map<String, Object?>?> load(String stateId) async {
  if (!_stateIdPattern.hasMatch(stateId)) return null;
  final cached = _memory[stateId];
  if (cached != null) return cached;
  if (dir != null) {
    final file = File(p.join(dir!, '$stateId.json'));
    if (await file.exists()) {
      final record = (jsonDecode(await file.readAsString()) as Map)
          .cast<String, Object?>();
      _memory[stateId] = record;
      return record;
    }
  }
  return null;
}