unsubscribe method

Future<void> unsubscribe([ String topic = "" ])

Unsubscribe from all subscription listeners with the specified topic.

If topic is not set, then this method will unsubscribe from all active subscriptions.

This method is no-op if there are no active subscriptions.

The related sse connection will be autoclosed if after the unsubscribe operation there are no active subscriptions left.

Implementation

Future<void> unsubscribe([String topic = ""]) async {
  var needToSubmit = false;

  if (topic.isEmpty) {
    // remove all subscriptions
    _subscriptions.clear();
  } else {
    final subs = _getSubscriptionsByTopic(topic);

    for (final key in subs.keys) {
      _subscriptions.remove(key);
      needToSubmit = true;
    }
  }

  // no other subscriptions -> close the sse connection
  if (!_hasNonEmptyTopic()) {
    return _disconnect();
  }

  // otherwise - notify the server about the subscription changes
  if (_clientId.isNotEmpty && needToSubmit) {
    return _submitSubscriptions();
  }
}