Fix thing reconfiguration after wifi connection loss

Author: pennam

src/ArduinoIoTCloudTCP.cpp

@@ -391,24 +391,21 @@ void ArduinoIoTCloudTCP::handleMessage(int length)
         case CommandId::ThingUpdateCmdId:
         {
           DEBUG_VERBOSE("ArduinoIoTCloudTCP::%s [%d] device configuration received", __FUNCTION__, millis());
-          if ( _thing_id != String(command.thingUpdateCmd.params.thing_id)) {
-            _thing_id = String(command.thingUpdateCmd.params.thing_id);
+          String new_thing_id = String(command.thingUpdateCmd.params.thing_id);
+
+          if (!new_thing_id.length()) {
+            /* Send message to device state machine to inform we have received a null thing-id */
+            _thing_id = "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx";
             Message message;
-            /* If we are attached we need first to detach */
-            if (_device.isAttached()) {
+            message = { DeviceRegisteredCmdId };
+            _device.handleMessage(&message);
+          } else {
+            if (_device.isAttached() && _thing_id != new_thing_id) {
               detachThing();
-              message = { DeviceDetachedCmdId };
             }
-            /* If received thing id is valid attach to the new thing */
-            if (_thing_id.length()) {
-              attachThing();
-              message = { DeviceAttachedCmdId };
-            } else {
-              /* Send message to device state machine to inform we have received a null thing-id */
-              _thing_id = "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx";
-              message = { DeviceRegisteredCmdId };
+            if (!_device.isAttached()) {
+              attachThing(new_thing_id);
             }
-            _device.handleMessage(&message);
           }
         }
         break;
@@ -491,17 +488,23 @@ void ArduinoIoTCloudTCP::sendPropertyContainerToCloud(String const topic, Proper
   }
 }
 
-void ArduinoIoTCloudTCP::attachThing()
+void ArduinoIoTCloudTCP::attachThing(String thingId)
 {
+  _thing_id = thingId;
 
   _dataTopicIn    = getTopic_datain();
   _dataTopicOut   = getTopic_dataout();
   if (!_mqttClient.subscribe(_dataTopicIn)) {
     DEBUG_ERROR("ArduinoIoTCloudTCP::%s could not subscribe to %s", __FUNCTION__, _dataTopicIn.c_str());
     DEBUG_ERROR("Check your thing configuration, and press the reset button on your board.");
+    _thing_id = "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx";
     return;
   }
 
+  Message message;
+  message = { DeviceAttachedCmdId };
+  _device.handleMessage(&message);
+
   DEBUG_INFO("Connected to Arduino IoT Cloud");
   DEBUG_INFO("Thing ID: %s", getThingId().c_str());
   execCloudEventCallback(ArduinoIoTCloudEvent::CONNECT);
@@ -514,6 +517,12 @@ void ArduinoIoTCloudTCP::detachThing()
     return;
   }
 
+  Message message;
+  message = { DeviceDetachedCmdId };
+  _device.handleMessage(&message);
+
+  _thing_id = "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx";
+
   DEBUG_INFO("Disconnected from Arduino IoT Cloud");
   execCloudEventCallback(ArduinoIoTCloudEvent::DISCONNECT);
 }

src/ArduinoIoTCloudTCP.h

@@ -170,7 +170,7 @@ class ArduinoIoTCloudTCP: public ArduinoIoTCloudClass
     void sendMessage(Message * msg);
     void sendPropertyContainerToCloud(String const topic, PropertyContainer & property_container, unsigned int & current_property_index);
 
-    void attachThing();
+    void attachThing(String thingId);
     void detachThing();
     int write(String const topic, byte const data[], int const length);