Unsibscribe to all MQTT topics before subscribing to new ones

code/espurna/mqtt.ino

@@ -180,6 +180,18 @@ void mqttSubscribe(const char * topic) {
     mqttSubscribeRaw(path.c_str());
 }
 
+void mqttUnsubscribeRaw(const char * topic) {
+    if (_mqtt.connected() && (strlen(topic) > 0)) {
+        #if MQTT_USE_ASYNC
+            unsigned int packetId = _mqtt.unsubscribe(topic);
+            DEBUG_MSG_P(PSTR("[MQTT] Unsubscribing to %s (PID %d)\n"), topic, packetId);
+        #else
+            _mqtt.unsubscribe(topic);
+            DEBUG_MSG_P(PSTR("[MQTT] Unsubscribing to %s\n"), topic);
+        #endif
+    }
+}
+
 void mqttRegister(void (*callback)(unsigned int, const char *, const char *)) {
     _mqtt_callbacks.push_back(callback);
 }
@@ -190,7 +202,6 @@ void mqttRegister(void (*callback)(unsigned int, const char *, const char *)) {
 
 void _mqttCallback(unsigned int type, const char * topic, const char * payload) {
 
-
     if (type == MQTT_CONNECT_EVENT) {
 
         mqttSubscribe(MQTT_TOPIC_ACTION);
@@ -226,6 +237,9 @@ void _mqttOnConnect() {
     // Send first Heartbeat
     heartbeat();
 
+    // Clean subscriptions
+    mqttUnsubscribeRaw("#");
+
     // Send connect event to subscribers
     for (unsigned char i = 0; i < _mqtt_callbacks.size(); i++) {
         (*_mqtt_callbacks[i])(MQTT_CONNECT_EVENT, NULL, NULL);