adding example of MQTT Weather API

Author: brentru

examples/mqtt/mqtt_weather.py

@@ -0,0 +1,79 @@
+"""
+Example of using the Adafruit IO MQTT Client
+for subscribing to the Adafruit IO Weather Service
+Note: This feature is avaliable for IO Plus Subscribers ONLY
+
+Author: Brent Rubell for Adafruit Industries
+"""
+
+# Import standard python modules.
+import sys
+
+# 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 = 'KEY'
+
+# Set to your Adafruit IO username.
+# (go to https://accounts.adafruit.com to find your username)
+ADAFRUIT_IO_USERNAME = 'USER'
+
+# Set to ID of the forecast to subscribe to for updates.
+forecast_id = 1234
+
+# Set to the ID of the feed to subscribe to for updates.
+"""
+Valid forecast types are:
+current
+forecast_minutes_5
+forecast_minutes_30
+forecast_hours_1
+forecast_hours_2
+forecast_hours_6
+forecast_hours_24
+forecast_days_1
+forecast_days_2
+forecast_days_5
+"""
+forecast_type = 'current'
+
+# 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.
+    print('Connected to Adafruit IO!  Listening for {0} changes...'.format(FEED_ID))
+    # Subscribe to changes on a feed named DemoFeed.
+    client.subscribe_weather(forecast_id, forecast_type)
+
+def disconnected(client):
+    # Disconnected function will be called when the client disconnects.
+    print('Disconnected from Adafruit IO!')
+    sys.exit(1)
+
+def message(client, feed_id, payload):
+    # Message function will be called when a subscribed feed has a new value.
+    # The feed_id parameter identifies the feed, and the payload parameter has
+    # the new value.
+    print('Weather Subscription {0} received new value: {1}'.format(forecast_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()
+
+# Start a message loop that blocks forever waiting for MQTT messages to be
+# received.  Note there are other options for running the event loop like doing
+# so in a background thread--see the mqtt_client.py example to learn more.
+client.loop_blocking()