startPairing method

Future<PairingCode> startPairing(String localId, { String joinerLabel = 'paired device', })

Starts sponsoring a device join for the already-open database localId.

Returns a one-time PairingCode to show the user. The other device calls pairWith with it; a PAKE over the transport authenticates the exchange, and this device seals the group key to the new one. If localId has no group key yet (a brand-new database), this founds it first.

Requires a configured Identity and PAKE. The armed session is single-use and replaced by the next startPairing call; cancelPairing drops it.

Implementation

Future<PairingCode> startPairing(
  String localId, {
  String joinerLabel = 'paired device',
}) async {
  final coordinator = _requirePairing();
  final db = _databases[localId];
  final rosterKey = _databaseKeys[localId];
  if (db == null || rosterKey == null) {
    throw StateError('Open database "$localId" before starting pairing.');
  }
  if (db.deviceState != DeviceState.ready) {
    await db.foundGroup();
  }
  return coordinator.arm(
    rosterKey: rosterKey,
    onAdmit: (joiner) async {
      await db.admitDevice(joiner, label: joinerLabel);
      return db.exportRosterPins();
    },
  );
}