adding group subscriptions

Author: brentru

Adafruit_IO/mqtt_client.py

@@ -99,21 +99,24 @@ def _mqtt_disconnect(self, client, userdata, rc):
 
     def _mqtt_message(self, client, userdata, msg):
         logger.debug('Client on_message called.')
-        # Parse out the feed id and call on_message callback.
-        # Assumes topic looks like "username/feeds/id"
+        """Parse out the topic and call on_message callback
+        assume topic looks like `username/topic/id`
+        """
         parsed_topic = msg.topic.split('/')
         if self.on_message is not None:
-            feed = parsed_topic[2]
+            topic = parsed_topic[2]
             payload = '' if msg.payload is None else msg.payload.decode('utf-8')
         elif self.on_message is not None and parsed_topic[0] == 'time':
-            feed = parsed_topic[0]
+            topic = parsed_topic[0]
+            payload = msg.payload.decode('utf-8')
+        elif self.on_message is not None and parsed_topic[1] == 'groups':
+            topic = parsed_topic[3]
             payload = msg.payload.decode('utf-8')
-        self.on_message(self, feed, payload)
+        self.on_message(self, topic, payload)
 
     def _mqtt_subscribe(client, userdata, mid, granted_qos):
         """Called when broker responds to a subscribe request."""
 
-
     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
@@ -179,15 +182,21 @@ def subscribe(self, feed_id, feed_user=None):
         the on_message function will be called with the feed_id and new value.
 
         Params:
-        - feed_id: The id of the feed to update.
-        - feed_user (optional): The user id of the feed. Used for feed sharing.
+        - feed_id: The id of the feed to subscribe to.
+        - feed_user (optional): The user id of the feed. Used for feed sharing functionality.
         """
         if feed_user is not None:
             (res, mid) = self._client.subscribe('{0}/feeds/{1}'.format(feed_user, feed_id))
         else:
             (res, mid) = self._client.subscribe('{0}/feeds/{1}'.format(self._username, feed_id))
         return res, mid
 
+    def subscribe_group(self, group_id):
+      """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.
+      """
+      self._client.subscribe('{0}/groups/{1}'.format(self._username, group_id))      
+
     def subscribe_time(self, time):
         """Subscribe to changes on the Adafruit IO time feeds. When the feed is
         updated, the on_message function will be called and publish a new value:
@@ -205,11 +214,11 @@ def subscribe_time(self, time):
             return
 
     def unsubscribe(self, feed_id):
-        """Unsubscribes from a specified MQTT feed.
-        Note: this does not prevent publishing to a feed, it will unsubscribe
-        from receiving messages via on_message.
-        """
-        (res, mid) = self._client.unsubscribe('{0}/feeds/{1}'.format(self._username, feed_id))
+      """Unsubscribes from a specified MQTT feed.
+      Note: this does not prevent publishing to a feed, it will unsubscribe
+      from receiving messages via on_message.
+      """
+      (res, mid) = self._client.unsubscribe('{0}/feeds/{1}'.format(self._username, feed_id))
 
     def publish(self, feed_id, value=None, feed_user=None):
         """Publish a value to a specified feed.

examples/mqtt/mqtt_group_subscribe.py

@@ -0,0 +1,58 @@
+# Example of using the MQTT client class to subscribe to and publish feed values.
+# Author: Tony DiCola
+
+# Import standard python modules.
+import random
+import sys
+import time
+
+# Import Adafruit IO MQTT client.
+from Adafruit_IO import MQTTClient
+
+# Set to your Adafruit IO key.
+# Remember, your key is a secret,
+# so make sure not to publish it when you publish this code!
+ADAFRUIT_IO_KEY = 'YOUR_AIO_KEY'
+
+# Set to your Adafruit IO username.
+# (go to https://accounts.adafruit.com to find your username)
+ADAFRUIT_IO_USERNAME = 'YOUR_AIO_USERNAME'
+
+# name of the group to subscribe to changes on
+group_name = 'grouptest'
+
+# Define callback functions which will be called when certain events happen.
+def connected(client):
+    # Connected function will be called when the client is connected to Adafruit IO.
+    # This is a good place to subscribe to feed changes.  The client parameter
+    # passed to this function is the Adafruit IO MQTT client so you can make
+    # calls against it easily.
+    # Subscribe to changes on a group_id.
+    print('Subscribing to ', group_name)
+    client.subscribe_group(group_name)
+
+def disconnected(client):
+    # Disconnected function will be called when the client disconnects.
+    print('Disconnected from Adafruit IO!')
+    sys.exit(1)
+
+def message(client, topic_id, payload):
+    # Message function will be called when a subscribed topic has a new value.
+    # The topic_id parameter identifies the topic, and the payload parameter has
+    # the new value.
+    print('{0} received new value: {1}'.format(topic_id, payload))
+
+
+# Create an MQTT client instance.
+client = MQTTClient(ADAFRUIT_IO_USERNAME, ADAFRUIT_IO_KEY)
+
+# Setup the callback functions defined above.
+client.on_connect    = connected
+client.on_disconnect = disconnected
+client.on_message    = message
+
+# Connect to the Adafruit IO server.
+client.connect()
+
+# Run a message loop forever to listen
+client.loop_blocking()