MQTT/REST Time Helpers (#54)

Add ability to subscribe to time topics via MQTT Client or REST/API Client. Add examples for each.

Author: brentru

Adafruit_IO/client.py

@@ -1,4 +1,4 @@
-# Copyright (c) 2014 Adafruit Industries
+# Copyright (c) 2018 Adafruit Industries
 # Authors: Justin Cooper & Tony DiCola
 
 # Permission is hereby granted, free of charge, to any person obtaining a copy
@@ -60,8 +60,11 @@ def __init__(self, username, key, proxies=None, base_url='https://io.adafruit.co
         # constructing the path.
         self.base_url = base_url.rstrip('/')
 
-    def _compose_url(self, path):
-        return '{0}/api/{1}/{2}/{3}'.format(self.base_url, self.api_version, self.username, path)
+    def _compose_url(self, path, is_time=None):
+        if not is_time:
+            return '{0}/api/{1}/{2}/{3}'.format(self.base_url, self.api_version, self.username, path)
+        else: # return a call to https://io.adafruit.com/api/v2/time/{unit}
+            return '{0}/api/{1}/{2}'.format(self.base_url, self.api_version, path)
 
 
     def _handle_error(self, response):
@@ -78,12 +81,15 @@ def _headers(self, given):
         headers.update(given)
         return headers
 
-    def _get(self, path):
-        response = requests.get(self._compose_url(path),
+    def _get(self, path, is_time=None):
+        response = requests.get(self._compose_url(path, is_time),
                                 headers=self._headers({'X-AIO-Key': self.key}),
                                 proxies=self.proxies)
         self._handle_error(response)
-        return response.json()
+        if not is_time:
+            return response.json()
+        else: # time doesn't need to serialize into json, just return text
+            return response.text
 
     def _post(self, path, data):
         response = requests.post(self._compose_url(path),
@@ -141,6 +147,15 @@ def send_location_data(self, feed, value, lat, lon, ele):
         """
         return self.create_data(feed, Data(value = value,lat=lat, lon=lon, ele=ele))
 
+    def receive_time(self, time):
+        """Returns the time from the Adafruit IO server.
+
+        args:
+            - time (string): millis, seconds, ISO-8601
+        """
+        timepath = "time/{0}".format(time)
+        return self._get(timepath, is_time=True)
+
     def receive(self, feed):
         """Retrieve the most recent value for the specified feed.  Feed can be a
         feed ID, feed key, or feed name.  Returns a Data instance whose value

Adafruit_IO/mqtt_client.py

@@ -100,7 +100,10 @@ def _mqtt_message(self, client, userdata, msg):
         if self.on_message is not None and self._username == parsed_topic[0]:
             feed = parsed_topic[2]
             payload = '' if msg.payload is None else msg.payload.decode('utf-8')
-            self.on_message(self, feed, payload)
+        elif self.on_message is not None and parsed_topic[0] == 'time':
+            feed = parsed_topic[0]
+            payload = msg.payload.decode('utf-8')
+        self.on_message(self, feed, payload)
 
     def connect(self, **kwargs):
         """Connect to the Adafruit.IO service.  Must be called before any loop
@@ -163,6 +166,22 @@ def subscribe(self, feed_id):
         """
         self._client.subscribe('{0}/feeds/{1}'.format(self._username, feed_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:
+        time =
+            millis: milliseconds
+            seconds: seconds
+            iso: ISO-8601 (https://en.wikipedia.org/wiki/ISO_8601)
+        """
+        if time == 'millis' or time == 'seconds':
+            self._client.subscribe('time/{0}'.format(time))
+        elif time == 'iso':
+            self._client.subscribe('time/ISO-8601')
+        else:
+            print('ERROR: Invalid time type specified')
+            return
+
     def publish(self, feed_id, value):
         """Publish a value to a specified feed.
 

examples/aio_basics/adafruitio_17_time.py

@@ -0,0 +1,38 @@
+"""
+adafruitio_17_time.py
+====================================
+Don't have a RTC handy and need
+accurate time measurements?
+
+Let Adafruit IO serve real-time values!
+
+Author: Brent Rubell
+"""
+# Import Adafruit IO REST client.
+from Adafruit_IO import Client, Feed, Data, RequestError
+
+# 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'
+
+# Create an instance of the REST client.
+aio = Client(ADAFRUIT_IO_USERNAME, ADAFRUIT_IO_KEY)
+
+print('---Adafruit IO REST API Time Helpers---')
+
+print('Seconds: aio.receive_time(seconds)')
+secs_val = aio.receive_time('seconds')
+print('\t' + secs_val)
+
+print('Milliseconds: aio.receive_time(millis)')
+ms_val = aio.receive_time('millis')
+print('\t' + ms_val)
+
+print('ISO-8601: aio.receive_time(ISO-8601)')
+iso_val = aio.receive_time('ISO-8601')
+print('\t' + iso_val)

examples/mqtt/mqtt_time.py

@@ -0,0 +1,64 @@
+"""
+mqtt_time.py
+============================================
+example of utilizing MQTT time topics to grab 
+the time from the Adafruit IO server.
+
+Author: Brent Rubell
+"""
+
+# Import standard python modules.
+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'
+
+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('\t Feed {0} received new value: {1}'.format(feed_id, payload))
+
+
+# Create a SECURE MQTT client instance
+# Note: This client will default to secure, an optional parameter can be added
+# to make it insecure, comment out the below line
+# client = MQTTClient(ADAFRUIT_IO_USERNAME, ADAFRUIT_IO_KEY, secure=False)
+client = MQTTClient(ADAFRUIT_IO_USERNAME, ADAFRUIT_IO_KEY)
+
+# Setup the callback functions defined above.
+client.on_disconnect = disconnected
+client.on_message = message
+
+# Connect to the Adafruit IO server.
+client.connect()
+
+# time per loop
+loop_time = 2
+
+client.loop_background()
+while True:
+    print('* Subscribing to /time/seconds')
+    client.subscribe_time('seconds')
+    time.sleep(loop_time)
+    print('* Subscribing to /time/millis')
+    client.subscribe_time('millis')
+    time.sleep(loop_time)
+    print('* Subscribing to iso-8601')
+    client.subscribe_time('iso')
+    time.sleep(loop_time)

setup.py

@@ -35,6 +35,6 @@
     keywords         = 'Adafruit IO',
     classifiers      = classifiers,
     description      = 'Client library for Adafruit IO (http://io.adafruit.com/).',
-    long_description = open('README.md').read(),
+    long_description = open('README.rst').read(),
     install_requires = ["requests", "paho-mqtt"]
 )