WebSockets MQTT Subscription Example

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#include "websocketiodevice.h" #include <QtCore/QDebug> WebSocketIODevice::WebSocketIODevice(QObject *parent) : QIODevice(parent) { connect(&m_socket, &QWebSocket::connected, this, &WebSocketIODevice::onSocketConnected); connect(&m_socket, &QWebSocket::binaryMessageReceived, this, &WebSocketIODevice::handleBinaryMessage); } bool WebSocketIODevice::open(QIODevice::OpenMode mode) { // Cannot use an URL because of missing sub protocol support // Have to use QNetworkRequest, see QTBUG-38742 QNetworkRequest request; request.setUrl(m_url); request.setRawHeader("Sec-WebSocket-Protocol", m_protocol.constData()); m_socket.open(request); return QIODevice::open(mode); } void WebSocketIODevice::close() { m_socket.close(); QIODevice::close(); } qint64 WebSocketIODevice::readData(char *data, qint64 maxlen) { qint64 bytesToRead = qMin(maxlen, (qint64)m_buffer.size()); memcpy(data, m_buffer.constData(), bytesToRead); m_buffer = m_buffer.right(m_buffer.size() - bytesToRead); return bytesToRead; } qint64 WebSocketIODevice::writeData(const char *data, qint64 len) { QByteArray msg(data, len); const int length = m_socket.sendBinaryMessage(msg); return length; } void WebSocketIODevice::setUrl(const QUrl &url) { m_url = url; } void WebSocketIODevice::setProtocol(const QByteArray &data) { m_protocol = data; } void WebSocketIODevice::handleBinaryMessage(const QByteArray &msg) { m_buffer.append(msg); emit readyRead(); } void WebSocketIODevice::onSocketConnected() { emit socketConnected(); }