웹소켓 MQTT 구독

class WebSocketIODevice : public QIODevice
{
    Q_OBJECT
public:
    WebSocketIODevice(QObject *parent = nullptr);

    bool isSequential() const override;
    qint64 bytesAvailable() const override;

    bool open(OpenMode mode) override;
    void close() override;

    qint64 readData(char *data, qint64 maxlen) override;
    qint64 writeData(const char *data, qint64 len) override;

    void setUrl(const QUrl &url);
    void setProtocol(const QByteArray &data);
Q_SIGNALS:
    void socketConnected();

public slots:
    void handleBinaryMessage(const QByteArray &msg);
    void onSocketConnected();

private:
    QByteArray m_protocol;
    QByteArray m_buffer;
    QWebSocket m_socket;
    QUrl m_url;
};

private:
    QMqttClient m_client;
    QMqttSubscription *m_subscription;
    QUrl m_url;
    QString m_topic;
    WebSocketIODevice m_device;
    int m_version;

void ClientSubscription::connectAndSubscribe() { qCDebug(lcWebSocketMqtt)<< "브로커에 연결 중 "<< m_url; m_device.setUrl(m_url); m_device.setProtocol(m_version== 3 ? "mqttv3.1": "mqtt"); connect(&m_device, &WebSocketIODevice::socketConnected, this, [this]() { qCDebug(lcWebSocketMqtt)<< "WebSocket 연결, MQTT 연결 초기화 중입니다."; m_client.setProtocolVersion(m_version== 3 ? QMqttClient::MQTT_3_1 : QMqttClient::MQTT_3_1_1); m_client.setTransport(&m_device, QMqttClient::IODevice); connect(&m_client, &QMqttClient::connected, this, [this]() { qCDebug(lcWebSocketMqtt)<< "MQTT 연결이 설정되었습니다"; m_subscription = m_client.subscribe(m_topic); if (!m_subscription) {                qDebug() << "Failed to subscribe to " << m_topic;
               emit errorOccured(); } connect(m_subscription, &.QMqttSubscription::stateChanged, [](QMqttSubscription::SubscriptionState s) { qCDebug(lcWebSocketMqtt)<< "구독 상태 변경됨:"<< s; }); connect(m_subscription, &QMqttSubscription::messageReceived, [this](QMqttMessage msg) { handleMessage(msg.payload()); }); }); m_client.connectToHost(); }); if (!m_device.open(QIODevice::ReadWrite))        qDebug() << "Could not open socket device";