QMQTT

mqtt client for Qt

Please compile the library with Qt >= 5.3 version. On Windows you need to specify CONFIG += NO_UNIT_TESTS, since gtest is not supported.

SSL is enabled by default, if the version of OpenSSL < 1.0.2, SSL may not be supported.

Disable the SSL in CMakeLists.txt (cmake):

option( ${PROJECT_NAME}_SSL "Enable SSL support for MQTT" OFF )

Disable the SSL with src/mqtt/qmqtt.pro (qmake):

CONFIG+=QMQTT_NO_SSL

To add websocket support, compile the library with Qt >= 5.7, and specify 'CONFIG += QMQTT_WEBSOCKETS'. This also works when compiling qmqtt for WebAssembly.

Usage

In your QMake project, add:

QT += qmqtt

Connect using TCP:

#include "qmqtt.h"

QMQTT::Client *client = new QMQTT::Client(QHostAddress::LocalHost, 1883);
client->setClientId("clientId");
client->setUsername("user");
client->setPassword("password");
client->connectToHost();

Connect using SSL:

QSslConfiguration sslConfig = QSslConfiguration::defaultConfiguration();
// Add custom SSL options here (for example extra certificates)
QMQTT::Client *client = new QMQTT::Client("example.com", 8883, sslConfig);
client->setClientId("clientId");
client->setUsername("user");
client->setPassword("password");
// Optionally, set ssl errors you want to ignore. Be careful, because this may weaken security.
// See QSslSocket::ignoreSslErrors(const QList<QSslError> &) for more information.
client->ignoreSslErrors(<list of expected ssl errors>)
client->connectToHost();
// Here's another option to suppress SSL errors (again, be careful)
QObject::connect(client, &QMQTT::Client::sslErrors, [&](const QList<QSslError> &errors) {
    // Investigate the errors here, if you find no serious problems, call ignoreSslErrors()
    // to continue connecting.
    client->ignoreSslErrors();
});

Connect using WebSockets:

QMQTT::Client *client = new QMQTT::Client("ws://www.example.com/mqtt", "<origin>", QWebSocketProtocol::VersionLatest);
client->setClientId("clientId");
client->setUsername("user");
client->setPassword("password");
client->connectToHost();

Slots

void setHost(const QHostAddress& host);
void setPort(const quint16 port);
void setClientId(const QString& clientId);
void setUsername(const QString& username);
void setPassword(const QString& password);
void setKeepAlive(const int keepAlive);
void setCleanSession(const bool cleansess);
void setAutoReconnect(const bool value);
void setAutoReconnectInterval(const int autoReconnectInterval);
void setWillTopic(const QString& willTopic);
void setWillQos(const quint8 willQos);
void setWillRetain(const bool willRetain);
void setWillMessage(const QString& willMessage);

void connectToHost();
void disconnectFromHost();

quint16 subscribe(const QString& topic, const quint8 qos);
void unsubscribe(const QString& topic);

quint16 publish(const Message& message);

Signals

void connected();
void disconnected();
void error(const QMQTT::ClientError error);

void subscribed(const QString& topic, const quint8 qos);
void unsubscribed(const QString& topic);
void published(const quint16 msgid, const quint8 qos);
void pingresp();
void received(const QMQTT::Message& message);