Merge pull request #107 from brentru/fix-subscribe-callbacks

MQTT_Client: Set QoS Level, Handle Subscription Callbacks

Author: brentru

Adafruit_IO/_version.py

@@ -1 +1 @@
-__version__ = "2.4.1"
+__version__ = "2.4.0"

Adafruit_IO/mqtt_client.py

@@ -1,5 +1,5 @@
-# Copyright (c) 2014 Adafruit Industries
-# Author: Tony DiCola
+# Copyright (c) 2020 Adafruit Industries
+# Author: Tony DiCola, Brent Rubell
 
 # Permission is hereby granted, free of charge, to any person obtaining a copy
 # of this software and associated documentation files (the "Software"), to deal
@@ -43,9 +43,10 @@ class MQTTClient(object):
     def __init__(self, username, key, service_host='io.adafruit.com', secure=True):
         """Create instance of MQTT client.
 
-            :param username: Adafruit.IO Username for your account.
-            :param key: Adafruit IO access key (AIO Key) for your account.
-            :param secure: (optional, boolean) Switches secure/insecure connections
+          :param username: Adafruit.IO Username for your account.
+          :param key: Adafruit IO access key (AIO Key) for your account.
+          :param secure: (optional, boolean) Switches secure/insecure connections
+
         """
         self._username = username
         self._service_host = service_host
@@ -70,6 +71,7 @@ def __init__(self, username, key, service_host='io.adafruit.com', secure=True):
         self._client.on_connect    = self._mqtt_connect
         self._client.on_disconnect = self._mqtt_disconnect
         self._client.on_message    = self._mqtt_message
+        self._client.on_subscribe  = self._mqtt_subscribe
         self._connected = False
 
 
@@ -95,7 +97,7 @@ def _mqtt_disconnect(self, client, userdata, rc):
         # log the RC as an error.  Continue on to call any disconnect handler
         # so clients can potentially recover gracefully.
         if rc != 0:
-            print("Unexpected disconnection.")
+            print('Unexpected disconnection.')
             raise MQTTError(rc)
         print('Disconnected from Adafruit IO!')
         # Call the on_disconnect callback if available.
@@ -105,6 +107,7 @@ def _mqtt_disconnect(self, client, userdata, rc):
     def _mqtt_message(self, client, userdata, msg):
         """Parse out the topic and call on_message callback
         assume topic looks like `username/topic/id`
+
         """
         logger.debug('Client on_message called.')
         parsed_topic = msg.topic.split('/')
@@ -124,15 +127,19 @@ def _mqtt_message(self, client, userdata, msg):
         else:
             raise ValueError('on_message not defined')
         self.on_message(self, topic, payload)
-    
-    def _mqtt_subscribe(client, userdata, mid, granted_qos):
+
+    def _mqtt_subscribe(self, client, userdata, mid, granted_qos):
         """Called when broker responds to a subscribe request."""
+        logger.debug('Client called on_subscribe')
+        if self.on_subscribe is not None:
+          self.on_subscribe(self, userdata, mid, granted_qos)
 
     def connect(self, **kwargs):
         """Connect to the Adafruit.IO service.  Must be called before any loop
         or publish operations are called.  Will raise an exception if a
         connection cannot be made.  Optional keyword arguments will be passed
         to paho-mqtt client connect function.
+
         """
         # Skip calling connect if already connected.
         if self._connected:
@@ -145,6 +152,7 @@ def connect(self, **kwargs):
 
     def is_connected(self):
         """Returns True if connected to Adafruit.IO and False if not connected.
+
         """
         return self._connected
 
@@ -157,9 +165,9 @@ def loop_background(self, stop=None):
         """Starts a background thread to listen for messages from Adafruit.IO
         and call the appropriate callbacks when feed events occur.  Will return
         immediately and will not block execution.  Should only be called once.
-        
-        Params:
-        - stop: boolean, stops the execution of the background loop.
+
+        :param bool stop: Stops the execution of the background loop.
+
         """
         if stop:
             self._client.loop_stop()
@@ -174,6 +182,7 @@ def loop_blocking(self):
         listen and respond to Adafruit.IO feed events.  If you need to do other
         processing, consider using the loop_background function to run a loop
         in the background.
+
         """
         self._client.loop_forever()
 
@@ -185,28 +194,36 @@ def loop(self, timeout_sec=1.0):
         The optional timeout_sec parameter specifies at most how long to block
         execution waiting for messages when this function is called.  The default
         is one second.
+
         """
         self._client.loop(timeout=timeout_sec)
 
-    def subscribe(self, feed_id, feed_user=None):
+    def subscribe(self, feed_id, feed_user=None, qos=0):
         """Subscribe to changes on the specified feed.  When the feed is updated
         the on_message function will be called with the feed_id and new value.
 
-        Params:
-        - feed_id: The id of the feed to subscribe to.
-        - feed_user (optional): The user id of the feed. Used for feed sharing functionality.
+        :param str feed_id: The key of the feed to subscribe to.
+        :param str feed_user: Optional, identifies feed owner. Used for feed sharing.
+        :param int qos: The QoS to use when subscribing. Defaults to 0.
+
         """
+        if qos > 1:
+            raise MQTTError("Adafruit IO only supports a QoS level of 0 or 1.")
         if feed_user is not None:
-            (res, mid) = self._client.subscribe('{0}/feeds/{1}'.format(feed_user, feed_id))
+            (res, mid) = self._client.subscribe('{0}/feeds/{1}'.format(feed_user, feed_id, qos=qos))
         else:
-            (res, mid) = self._client.subscribe('{0}/feeds/{1}'.format(self._username, feed_id))
+            (res, mid) = self._client.subscribe('{0}/feeds/{1}'.format(self._username, feed_id), qos=qos)
         return res, mid
 
-    def subscribe_group(self, group_id):
+    def subscribe_group(self, group_id, qos=0):
       """Subscribe to changes on the specified group. When the group is updated
       the on_message function will be called with the group_id and the new value.
+
+      :param str feed_id: The key of the feed to subscribe to.
+      :param int qos: The QoS to use when subscribing. Defaults to 0.
+
       """
-      self._client.subscribe('{0}/groups/{1}'.format(self._username, group_id))
+      self._client.subscribe('{0}/groups/{1}'.format(self._username, group_id), qos=qos)
 
     def subscribe_randomizer(self, randomizer_id):
       """Subscribe to changes on a specified random data stream from
@@ -216,6 +233,7 @@ def subscribe_randomizer(self, randomizer_id):
       every client that is subscribed to the same topic.
 
       :param int randomizer_id: ID of the random word record you want data for.
+
       """
       self._client.subscribe('{0}/integration/words/{1}'.format(self._username, randomizer_id))
 

examples/mqtt/mqtt_subscribe.py

@@ -31,6 +31,10 @@ def connected(client):
     # Subscribe to changes on a feed named DemoFeed.
     client.subscribe(FEED_ID)
 
+def subscribe(client, userdata, mid, granted_qos):
+    # This method is called when the client subscribes to a new feed.
+    print('Subscribed to {0} with QoS {1}'.format(FEED_ID, granted_qos[0]))
+
 def disconnected(client):
     # Disconnected function will be called when the client disconnects.
     print('Disconnected from Adafruit IO!')
@@ -50,6 +54,7 @@ def message(client, feed_id, payload):
 client.on_connect    = connected
 client.on_disconnect = disconnected
 client.on_message    = message
+client.on_subscribe  = subscribe
 
 # Connect to the Adafruit IO server.
 client.connect()