From 2e5d5e3cfcf87c27f912d85dac38ff926f2413d7 Mon Sep 17 00:00:00 2001
From: Maurice Kalinowski <maurice.kalinowski@qt.io>
Date: Mon, 23 Jan 2017 14:50:49 +0100
Subject: [PATCH] Send ping on keepAlive

The broker expects a ping from each client to be received within
KeepAlive * 1.5 timeframe. If there is non received, the broker will
disconnect.
---
 src/mqtt/qmqttconnection.cpp | 9 ++++++++-
 src/mqtt/qmqttconnection_p.h | 4 +++-
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/mqtt/qmqttconnection.cpp b/src/mqtt/qmqttconnection.cpp
index b42ed55..ace8757 100644
--- a/src/mqtt/qmqttconnection.cpp
+++ b/src/mqtt/qmqttconnection.cpp
@@ -35,7 +35,8 @@ QT_BEGIN_NAMESPACE
 
 QMqttConnection::QMqttConnection(QObject *parent) : QObject(parent)
 {
-
+    m_pingTimer.setSingleShot(false);
+    m_pingTimer.connect(&m_pingTimer, &QTimer::timeout, this, &QMqttConnection::sendControlPingRequest);
 }
 
 QMqttConnection::~QMqttConnection()
@@ -214,6 +215,8 @@ bool QMqttConnection::sendControlPingRequest()
 
 bool QMqttConnection::sendControlDisconnect()
 {
+    m_pingTimer.stop();
+
     const QMqttControlPacket packet(QMqttControlPacket::DISCONNECT);
     if (!writePacketToTransport(packet)) {
         qWarning("Could not write DISCONNECT frame to transport");
@@ -237,6 +240,7 @@ void QMqttConnection::setClient(QMqttClient *client)
 void QMqttConnection::transportConnectionClosed()
 {
     qWarning("Transport Connection closed!");
+    m_pingTimer.stop();
     m_client->setState(QMqttClient::Disconnected);
 }
 
@@ -282,6 +286,9 @@ void QMqttConnection::transportReadReady()
         }
         m_internalState = BrokerConnected;
         m_client->setState(QMqttClient::Connected);
+
+        m_pingTimer.setInterval(m_client->keepAlive() * 1000);
+        m_pingTimer.start();
         break;
     }
     case QMqttControlPacket::SUBACK: {
diff --git a/src/mqtt/qmqttconnection_p.h b/src/mqtt/qmqttconnection_p.h
index f419cf1..cdbb315 100644
--- a/src/mqtt/qmqttconnection_p.h
+++ b/src/mqtt/qmqttconnection_p.h
@@ -43,7 +43,8 @@
 
 #include "qmqttclient.h"
 #include "qmqttcontrolpacket_p.h"
-#include <QObject>
+#include <QtCore/QObject>
+#include <QtCore/QTimer>
 
 QT_BEGIN_NAMESPACE
 
@@ -99,6 +100,7 @@ private:
     bool writePacketToTransport(const QMqttControlPacket &p);
     QSet<quint16> m_pendingSubscriptionAck;
     InternalConnectionState m_internalState{BrokerDisconnected};
+    QTimer m_pingTimer;
 };
 
 QT_END_NAMESPACE