make user_data "public"

adafruit_minimqtt/adafruit_minimqtt.py

@@ -168,7 +168,10 @@ class MQTT:
         in seconds.
     :param int connect_retries: How many times to try to connect to the broker before giving up
         on connect or reconnect. Exponential backoff will be used for the retries.
-    :param class user_data: arbitrary data to pass as a second argument to the callbacks.
+    :param class user_data: arbitrary data to pass as a second argument to most of the callbacks.
+        This works with all callbacks but the "on_message" and those added via add_topic_callback();
+        for those, to get access to the user_data use the 'user_data' member of the MQTT object
+        passed as 1st argument.
 
     """
 
@@ -205,7 +208,7 @@ def __init__(
         self._recv_timeout = recv_timeout
 
         self.keep_alive = keep_alive
-        self._user_data = user_data
+        self.user_data = user_data
         self._is_connected = False
         self._msg_size_lim = MQTT_MSG_SZ_LIM
         self._pid = 0
@@ -413,6 +416,11 @@ def add_topic_callback(self, mqtt_topic: str, callback_method) -> None:
 
         :param str mqtt_topic: MQTT topic identifier.
         :param function callback_method: The callback method.
+
+        Expected method signature is ``on_message(client, topic, message)``
+        To get access to the user_data, use the client argument.
+
+        If a callback is called for the topic, then any "on_message" callback will not be called.
         """
         if mqtt_topic is None or callback_method is None:
             raise ValueError("MQTT topic and callback method must both be defined.")
@@ -437,6 +445,7 @@ def on_message(self):
         """Called when a new message has been received on a subscribed topic.
 
         Expected method signature is ``on_message(client, topic, message)``
+        To get access to the user_data, use the client argument.
         """
         return self._on_message
 
@@ -638,7 +647,7 @@ def _connect(
                 self._is_connected = True
                 result = rc[0] & 1
                 if self.on_connect is not None:
-                    self.on_connect(self, self._user_data, result, rc[2])
+                    self.on_connect(self, self.user_data, result, rc[2])
 
                 return result
 
@@ -661,7 +670,7 @@ def disconnect(self) -> None:
         self._is_connected = False
         self._subscribed_topics = []
         if self.on_disconnect is not None:
-            self.on_disconnect(self, self._user_data, 0)
+            self.on_disconnect(self, self.user_data, 0)
 
     def ping(self) -> list[int]:
         """Pings the MQTT Broker to confirm if the broker is alive or if
@@ -757,7 +766,7 @@ def publish(
         self._sock.send(pub_hdr_var)
         self._sock.send(msg)
         if qos == 0 and self.on_publish is not None:
-            self.on_publish(self, self._user_data, topic, self._pid)
+            self.on_publish(self, self.user_data, topic, self._pid)
         if qos == 1:
             stamp = time.monotonic()
             while True:
@@ -769,7 +778,7 @@ def publish(
                     rcv_pid = rcv_pid_buf[0] << 0x08 | rcv_pid_buf[1]
                     if self._pid == rcv_pid:
                         if self.on_publish is not None:
-                            self.on_publish(self, self._user_data, topic, rcv_pid)
+                            self.on_publish(self, self.user_data, topic, rcv_pid)
                         return
 
                 if op is None:
@@ -849,7 +858,7 @@ def subscribe(self, topic: str, qos: int = 0) -> None:
 
                     for t, q in topics:
                         if self.on_subscribe is not None:
-                            self.on_subscribe(self, self._user_data, t, q)
+                            self.on_subscribe(self, self.user_data, t, q)
                         self._subscribed_topics.append(t)
                     return
 
@@ -907,7 +916,7 @@ def unsubscribe(self, topic: str) -> None:
                     assert rc[1] == packet_id_bytes[0] and rc[2] == packet_id_bytes[1]
                     for t in topics:
                         if self.on_unsubscribe is not None:
-                            self.on_unsubscribe(self, self._user_data, t, self._pid)
+                            self.on_unsubscribe(self, self.user_data, t, self._pid)
                         self._subscribed_topics.remove(t)
                     return
 

examples/cpython/user_data.py

@@ -0,0 +1,99 @@
+# SPDX-FileCopyrightText: 2023 Vladimír Kotal
+# SPDX-License-Identifier: Unlicense
+
+# pylint: disable=logging-fstring-interpolation
+
+"""
+Demonstrate on how to use user_data for various callbacks.
+"""
+
+import logging
+import socket
+import ssl
+import sys
+
+import adafruit_minimqtt.adafruit_minimqtt as MQTT
+
+
+# pylint: disable=unused-argument
+def on_connect(mqtt_client, user_data, flags, ret_code):
+    """
+    connect callback
+    """
+    logger = logging.getLogger(__name__)
+    logger.debug("Connected to MQTT Broker!")
+    logger.debug(f"Flags: {flags}\n RC: {ret_code}")
+
+
+# pylint: disable=unused-argument
+def on_subscribe(mqtt_client, user_data, topic, granted_qos):
+    """
+    subscribe callback
+    """
+    logger = logging.getLogger(__name__)
+    logger.debug(f"Subscribed to {topic} with QOS level {granted_qos}")
+
+
+def on_message(client, topic, message):
+    """
+    received message callback
+    """
+    logger = logging.getLogger(__name__)
+    logger.debug(f"New message on topic {topic}: {message}")
+
+    messages = client.user_data
+    if not messages.get(topic):
+        messages[topic] = []
+    messages[topic].append(message)
+
+
+# pylint: disable=too-many-statements,too-many-locals
+def main():
+    """
+    Main loop.
+    """
+
+    logging.basicConfig()
+    logger = logging.getLogger(__name__)
+    logger.setLevel(logging.DEBUG)
+
+    # dictionary/map of topic to list of messages
+    messages = {}
+
+    # connect to MQTT broker
+    mqtt = MQTT.MQTT(
+        broker="172.40.0.3",
+        port=1883,
+        socket_pool=socket,
+        ssl_context=ssl.create_default_context(),
+        user_data=messages,
+    )
+
+    mqtt.on_connect = on_connect
+    mqtt.on_subscribe = on_subscribe
+    mqtt.on_message = on_message
+
+    logger.info("Connecting to MQTT broker")
+    mqtt.connect()
+    logger.info("Subscribing")
+    mqtt.subscribe("foo/#", qos=0)
+    mqtt.add_topic_callback("foo/bar", on_message)
+
+    i = 0
+    while True:
+        i += 1
+        logger.debug(f"Loop {i}")
+        # Make sure to stay connected to the broker e.g. in case of keep alive.
+        mqtt.loop(1)
+
+        for topic, msg_list in messages.items():
+            logger.info(f"Got {len(msg_list)} messages from topic {topic}")
+            for msg_cnt, msg in enumerate(msg_list):
+                logger.debug(f"#{msg_cnt}: {msg}")
+
+
+if __name__ == "__main__":
+    try:
+        main()
+    except KeyboardInterrupt:
+        sys.exit(0)