Transferring data over socket failed: The client is not connected to a broker. The requested operation is impossible at this point. about laravel-client

[Namoshek]

I think it is because you are calling $mqtt->disconnect() in both methods. The ConnectionManager (which is what is used behind the MQTT facade) does not know that you are disconnecting and will not call connect() for you the second time.

My advice would be to remove both calls to $mqtt->disconnect() and add one single call to MQTT::disconnect() before returning the response.

[pheelaphong]

Thank you very much. I removed all $mqtt->disconnect();, but somtimes the returned message is empty:

[
  {
    device_id: 10000,
    status: "Online",
    power: "OFF"
  },
  {
    device_id: 10001,
    status: "Online",
    power: "OFF"
  },
  {
    device_id: 10002,
    status: "Online",
    power: ""
  },
  {
    device_id: 10003,
    status: "",
    power: ""
  },
  {
    device_id: 10004,
    status: "",
    power: ""
  }
]

My code now:

public function subDeviceAll(Request $request)
{
    $device = Device::all();
    $dataDevice = [];
    foreach ($device as $key => $value) {
        //$data['data_device'] = $value;
        $data['device_id'] = $value['device_id'];
        $data['status'] = $this->checkDeviceOnline($value['device_id']);
        $data['power'] = $this->checkDevicePower($value['device_id']);
        $dataDevice[] = $data;
    }
    return response()->json($dataDevice, 200);
}

public function checkDeviceOnline($device_id)
{
    $device = Device::where('device_id', $device_id)->first();
    $mqtt = MQTT::connection();
    $res = '';
    $topic = $device['topic'];

    $mqtt->publish('cmnd/' . $topic . '/POWER', '', 2);
    $mqtt->subscribe('tele/' . $topic . '/LWT', function (string $topic, string $message) use ($mqtt, &$res) {
        $res = $message;
        $mqtt->interrupt();
    }, 1);

    $mqtt->loop(true);
    return $res;
}

public function checkDevicePower($device_id)
{
    $device = Device::where('device_id', $device_id)->first();
    $mqtt = MQTT::connection();
    $res = '';
    $topic = $device['topic'];

    $mqtt->publish('cmnd/' . $topic . '/POWER', '', 2);
    $mqtt->subscribe('stat/' . $topic . '/POWER', function (string $topic, string $message) use ($mqtt, &$res) {
        $res = $message;
        $mqtt->interrupt();
    }, 1);
    $mqtt->loop(true);
    return $res;
}

[Namoshek]

Well, that has nothing to do with the library but your devices. I cannot help you with that part.