subscripeToSubscription method

dynamic subscripeToSubscription(Map<String, String> query, Function callBackFunc)

Implementation

subscripeToSubscription(Map<String, String> query, Function callBackFunc) async {
  print("**************************************");
  print("**************************************");
  try {
    var data = await http.post(
        Uri.https('$_endpoint', 'graphql'),
      headers: {
        'x-api-key': _apiKey,
        'Content-Type': 'application/json',
      },
      body: json.encode(query),
      );
    print(data);
    Map<String, dynamic> response =
        jsonDecode(data.body) as Map<String, dynamic>;

    var server;
    var clientIdentifier;
    var topic;
    topic= response['extensions']['subscription']['mqttConnections'][0]
                        ['topics'][0];


    for (var m in response['extensions']['subscription']['mqttConnections']) {
      if ((m['topics'] as List<dynamic>).contains(topic)) {
        server=m['url'];
        clientIdentifier=m['client'];
        break;
      }
    }

    final client = MqttServerClient(server.toString(),  clientIdentifier.toString());
    client.port = _port;
    client.logging(on: false);
    client.keepAlivePeriod = 30;
    client.useWebSocket = true;

    client.onDisconnected = onDisconnected;
    client.onConnected = onConnected;

    try {
      await client.connect();
      client.subscribe(topic.toString(), MqttQos.atMostOnce);

      client.updates?.listen((List<MqttReceivedMessage<MqttMessage>> c) {
        final MqttPublishMessage recMess =
            c[0].payload as MqttPublishMessage;
        final String results = MqttPublishPayload.bytesToStringAsString(
            recMess.payload.message);

        client.disconnect();

        return callBackFunc(results);
      });

    } on NoConnectionException catch (e) {
      print('client exception: $e');
      client.disconnect();
    } on SocketException catch (e) {
      print('socket exception: $e');
      client.disconnect();
    }

  } catch (e) {
    print(e);
  }
}