--- a/mqtt/library.py	Tue Jan 21 09:29:59 2025 +0100
+++ b/mqtt/library.py	Tue Jan 21 16:28:43 2025 +0100
@@ -22,11 +22,14 @@
     res = c_function(topic, payload, len(payload), QoS, Retained)
     return res
 
-# C per client CallBack type for __mqtt_python_subscribe_{name}
-c_cb_type = ctypes.CFUNCTYPE(ctypes.c_int,                   # return
-                             ctypes.c_char_p,                # topic
-                             ctypes.POINTER(ctypes.c_char),  # data
-                             ctypes.c_uint32)                # data length
+# C per client CallBack type for __mqtt_python_onmsg_{name}
+mqtt_c_cb_onmsg_type = ctypes.CFUNCTYPE(ctypes.c_int,                   # return
+                                        ctypes.c_char_p,                # topic
+                                        ctypes.POINTER(ctypes.c_char),  # data
+                                        ctypes.c_uint32)                # data length
+
+# C per client CallBack type for __mqtt_python_resub_{name}
+mqtt_c_cb_resub_type = ctypes.CFUNCTYPE(ctypes.c_int)                  # return
 
 # CallBacks management
 # - each call to MQTT_subscribe registers a callback
@@ -35,18 +38,21 @@
 # - one callback registered to C side per client
 MQTT_client_cbs = {}
 
-def per_client_cb_factory(client):
-    def per_client_cb(topic, dataptr, datalen):
+def mqtt_per_client_cb_factory(client):
+    def per_client_onmsg_cb(topic, dataptr, datalen):
         payload = ctypes.string_at(dataptr, datalen)
-        subscriber = MQTT_subscribers_cbs[client].get(topic, None)
+        subscriber,_Qos = MQTT_subscribers_cbs[client].get(topic, None)
         if subscriber:
             subscriber(topic, payload)
             return 0
         return 1
-    return per_client_cb
+    def per_client_resub_cb():
+        for topic,(_cb,Qos) in MQTT_subscribers_cbs[client].items():
+            _MQTT_subscribe(clientname, topic, QoS)
+        return 1
+    return per_client_onmsg_cb,per_client_resub_cb
     
-def MQTT_subscribe(clientname, topic, cb, QoS = 1):
-    global MQTT_client_cbs, MQTT_subscribers_cbs
+def _MQTT_subscribe(clientname, topic, QoS):
     c_function_name = "__mqtt_python_subscribe_" + clientname
     c_function = getattr(PLCBinary, c_function_name)
     c_function.restype = ctypes.c_int # error or 0
@@ -54,17 +60,24 @@
         ctypes.c_char_p,  # topic
         ctypes.c_uint8]   # QoS
 
-    MQTT_subscribers_cbs.setdefault(clientname, {})[topic] = cb
+    return c_function(topic, QoS)
 
-    c_cb = MQTT_client_cbs.get(clientname, None)
-    if c_cb is None:
-        c_cb = c_cb_type(per_client_cb_factory(clientname))
-        MQTT_client_cbs[clientname] = c_cb
+def MQTT_subscribe(clientname, topic, cb, QoS = 1):
+    global MQTT_client_cbs, MQTT_subscribers_cbs
+
+    MQTT_subscribers_cbs.setdefault(clientname, {})[topic] = (cb, QoS)
+    res = _MQTT_subscribe(clientname, topic, QoS)
+
+    c_cbs = MQTT_client_cbs.get(clientname, None)
+    if c_cbs is None:
+        cb_onmsg, cb_resub = mqtt_per_client_cb_factory(clientname)
+        c_cbs = (mqtt_c_cb_onmsg_type(cb_onmsg),
+                 mqtt_c_cb_resub_type(cb_resub))
+        MQTT_client_cbs[clientname] = c_cbs
         register_c_function = getattr(PLCBinary, "__mqtt_python_callback_setter_"+clientname )
-        register_c_function.argtypes = [c_cb_type]
-        register_c_function(c_cb)
+        register_c_function.argtypes = [mqtt_c_cb_onmsg_type, mqtt_c_cb_resub_type]
+        register_c_function(*c_cbs)
 
-    res = c_function(topic, QoS)
     return res
 
 """

--- a/mqtt/mqtt_template.c	Tue Jan 21 09:29:59 2025 +0100
+++ b/mqtt/mqtt_template.c	Tue Jan 21 16:28:43 2025 +0100
@@ -260,8 +260,11 @@
 }}
 
 
-typedef int(*callback_fptr_t)(char* topic, char* data, uint32_t datalen);
-static callback_fptr_t __mqtt_python_callback_fptr_{name} = NULL;
+typedef int(*cb_onmsg_fptr_t)(char* topic, char* data, uint32_t datalen);
+static cb_onmsg_fptr_t __mqtt_python_cb_onmsg_fptr_{name} = NULL;
+
+typedef int(*cb_resub_fptr_t)(void);
+static cb_resub_fptr_t __mqtt_python_cb_resub_fptr_{name} = NULL;
 
 static int messageArrived(void *context, char *topicName, int topicLen, MQTTClient_message *message)
 {{
@@ -309,8 +312,8 @@
             high = mid - 1;
     }}
     // If we reach here, then the element was not present
-    if(__mqtt_python_callback_fptr_{name} && 
-       (*__mqtt_python_callback_fptr_{name})(topicName,
+    if(__mqtt_python_cb_onmsg_fptr_{name} && 
+       (*__mqtt_python_cb_onmsg_fptr_{name})(topicName,
                                      (char*)message->payload,
                                      message->payloadlen) == 0){{
         // Topic was handled in python
@@ -458,6 +461,10 @@
 
 {init_pubsub}
 
+    if(__mqtt_python_cb_resub_fptr_{name}){{ 
+        (*__mqtt_python_cb_resub_fptr_{name})();
+    }}
+
     return MQTTCLIENT_SUCCESS;
 }}
 
@@ -630,8 +637,9 @@
     return 0;
 }}
 
-int __mqtt_python_callback_setter_{name}(callback_fptr_t cb)
-{{
-    __mqtt_python_callback_fptr_{name} = cb;
+int __mqtt_python_callback_setter_{name}(cb_onmsg_fptr_t cb_onmsg, cb_resub_fptr_t cb_resub)
+{{
+    __mqtt_python_cb_onmsg_fptr_{name} = cb_onmsg;
+    __mqtt_python_cb_resub_fptr_{name} = cb_resub;
     return 0;
 }}