WebSockets MQTT Subscription Example

 // Copyright (C) 2017 The Qt Company Ltd.
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause

 #ifndef CLIENTSUBSCRIPTION_H
 #define CLIENTSUBSCRIPTION_H

 #include "websocketiodevice.h"

 #include <QtCore/QObject>
 #include <QtMqtt/QMqttClient>
 #include <QtWebSockets/QWebSocket>

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

     void setUrl(const QUrl &url); // ie ws://broker.hivemq.com:8000/mqtt
     void setTopic(const QString &topic);
     void setVersion(int v);
 signals:
     void messageReceived(QByteArray);
     void errorOccured();

 public slots:
     void connectAndSubscribe();
     void handleMessage(const QByteArray &msgContent);

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

 #endif // CLIENTSUBSCRIPTION_H