Replace the polling task MqttHandling with a function called by Async-MQTT-Client KeepAlive

[obrain17]

Improvement of MQTT Re-Connect

Replace the polling task

xTaskCreatePinnedToCore(&MqttHandling, "MqttTask", defaultThreadStackSize, (void *)&mqtt, defaultThreadPriority, NULL, 0);

that is periodically calling the function

void Basecamp::MqttHandling(void *mqttPointer)

with a function that is called only on MQTT disconnect by the Async-MQTT-Client KeepAlive functionality.

Create a timer and register an onDisconnect callback function that manages the (re)connection of the MQTT client. It will be called by the Asyc-MQTT-Client KeepAlive function if a connection loss is detected. The timer is then started and will start a function to reconnect MQTT after 2 seconds

    mqttReconnectTimer = xTimerCreate("mqttTimer", pdMS_TO_TICKS(2000), pdFALSE, (void*)&mqtt, reinterpret_cast<TimerCallbackFunction_t>(connectToMqtt));
    mqtt.onDisconnect(onMqttDisconnect);

Async-MQTT-Client will call the callback

• every time the connection is lost and if
• unsuccessful attempts are made to re-connect.

If WiFi is not available the timer will be restarted to try again after 2 seconds.

The functionality was successfully tested with

• Stop and restart Mosquitto MQTT brooker
• Disable and enable Wifi on Fritz-Box

In both cases the MQTT connection was established again.

Tests with mqttGuard have yet to be done.