Merge pull request #2 from adafruit/mqtt_client

Add MQTT client, refactor tests to use unittest module.

Author: tdicola

Adafruit_IO/__init__.py

@@ -1 +1,2 @@
-from .client import Client, AdafruitIOError, RequestError, ThrottlingError
+from .client import Client, AdafruitIOError, RequestError, ThrottlingError
+from .mqtt_client import MQTTClient

Adafruit_IO/client.py

@@ -78,33 +78,33 @@ def _post(self, path, params):
   #stream functionality
   def send(self, feed_name, data):
     feed_name = quote(feed_name)
-    path = "api/feeds/{}/streams/send".format(feed_name)
+    path = "api/feeds/{}/data/send".format(feed_name)
     return self._post(path, {'value': data})
 
   def receive(self, feed_name):
     feed_name = quote(feed_name)
-    path = "api/feeds/{}/streams/last".format(feed_name)
+    path = "api/feeds/{}/data/last".format(feed_name)
     return self._get(path)
 
   def receive_next(self, feed_name):
     feed_name = quote(feed_name)
-    path = "api/feeds/{}/streams/next".format(feed_name)
+    path = "api/feeds/{}/data/next".format(feed_name)
     return self._get(path)
 
   def receive_previous(self, feed_name):
     feed_name = quote(feed_name)
-    path = "api/feeds/{}/streams/last".format(feed_name)
+    path = "api/feeds/{}/data/last".format(feed_name)
     return self._get(path)
 
   def streams(self, feed_id_or_key, stream_id=None):
     if stream_id is None:
-      path = "api/feeds/{}/streams".format(feed_id_or_key)
+      path = "api/feeds/{}/data".format(feed_id_or_key)
     else:
-      path = "api/feeds/{}/streams/{}".format(feed_id_or_key, stream_id)
+      path = "api/feeds/{}/data/{}".format(feed_id_or_key, stream_id)
     return self._get(path)
 
   def create_stream(self, feed_id_or_key, data):
-    path = "api/feeds/{}/streams".format(feed_id_or_key)
+    path = "api/feeds/{}/data".format(feed_id_or_key)
     return self._post(path, data)
 
   #group functionality

Adafruit_IO/mqtt_client.py

@@ -0,0 +1,145 @@
+# MQTT-based client for Adafruit.IO
+# Author: Tony DiCola ([email protected])
+#
+# Supports publishing and subscribing to feed changes from Adafruit IO using
+# the MQTT protcol.
+#
+# Depends on the following Python libraries:
+# - paho-mqtt: Paho MQTT client for python.
+import logging
+
+import paho.mqtt.client as mqtt
+
+
+SERVICE_HOST   = 'io.adafruit.com'
+SERVICE_PORT   = 1883
+KEEP_ALIVE_SEC = 3600  # One minute
+
+logger = logging.getLogger(__name__)
+
+
+class MQTTClient(object):
+    """Interface for publishing and subscribing to feed changes on Adafruit IO
+    using the MQTT protocol.
+    """
+
+    def __init__(self, key):
+        """Create instance of MQTT client.
+
+        Required parameters:
+        - key: The Adafruit.IO access key for your account.
+        """
+        # Initialize event callbacks to be None so they don't fire.
+        self.on_connect    = None
+        self.on_disconnect = None
+        self.on_message    = None
+        # Initialize MQTT client.
+        self._client = mqtt.Client()
+        self._client.username_pw_set(key)
+        self._client.on_connect    = self._mqtt_connect
+        self._client.on_disconnect = self._mqtt_disconnect
+        self._client.on_message    = self._mqtt_message
+        self._connected = False
+
+    def _mqtt_connect(self, client, userdata, flags, rc):
+        logger.debug('Client on_connect called.')
+        # Check if the result code is success (0) or some error (non-zero) and
+        # raise an exception if failed.
+        if rc == 0:
+            self._connected = True
+        else:
+            # TODO: Make explicit exception classes for these failures:
+            # 0: Connection successful 1: Connection refused - incorrect protocol version 2: Connection refused - invalid client identifier 3: Connection refused - server unavailable 4: Connection refused - bad username or password 5: Connection refused - not authorised 6-255: Currently unused.
+            raise RuntimeError('Error connecting to Adafruit IO with rc: {0}'.format(rc))
+        # Call the on_connect callback if available.
+        if self.on_connect is not None:
+            self.on_connect(self)
+
+    def _mqtt_disconnect(self, client, userdata, rc):
+        logger.debug('Client on_disconnect called.')
+        self._connected = False
+        # If this was an unexpected disconnect (non-zero result code) then raise
+        # an exception.
+        if rc != 0:
+            raise RuntimeError('Unexpected disconnect with rc: {0}'.format(rc))
+        # Call the on_disconnect callback if available.
+        if self.on_disconnect is not None:
+            self.on_disconnect(self)
+
+    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 "api/feeds/{feed_id}/data/receive.json"
+        if self.on_message is not None and msg.topic.startswith('api/feeds/') \
+            and len(msg.topic) >= 28:
+            feed_id = msg.topic[10:-18]
+            self.on_message(self, feed_id, msg.payload)
+
+    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:
+            return
+        # Connect to the Adafruit IO MQTT service.
+        self._client.connect(SERVICE_HOST, port=SERVICE_PORT, 
+            keepalive=KEEP_ALIVE_SEC, **kwargs)
+
+    def is_connected(self):
+        """Returns True if connected to Adafruit.IO and False if not connected.
+        """
+        return self._connected
+
+    def disconnect(self):
+        # Disconnect MQTT client if connected.
+        if self._connected:
+            self._client.disconnect()
+
+    def loop_background(self):
+        """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.
+        """
+        self._client.loop_start()
+
+    def loop_blocking(self):
+        """Listen for messages from Adafruit.IO and call the appropriate
+        callbacks when feed events occur.  This call will block execution of
+        your program and will not return until disconnect is explicitly called.
+
+        This is useful if your program doesn't need to do anything else except
+        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()
+
+    def loop(self, timeout_sec=1.0):
+        """Manually process messages from Adafruit.IO.  This is meant to be used
+        inside your own main loop, where you periodically call this function to
+        make sure messages are being processed to and from Adafruit_IO.
+
+        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):
+        """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.
+        """
+        self._client.subscribe('api/feeds/{0}/data/receive.json'.format(feed_id))
+
+    def publish(self, feed_id, value):
+        """Publish a value to a specified feed.
+
+        Required parameters:
+        - feed_id: The id of the feed to update.
+        - value: The new value to publish to the feed.
+        """
+        self._client.publish('api/feeds/{0}/data/send.json'.format(feed_id),
+            payload=value)

examples/mqtt_client.py

@@ -0,0 +1,87 @@
+# Example of using the MQTT client class to subscribe to and publish feed values.
+# Author: Tony DiCola ([email protected])
+
+# Import standard python modules.
+import random
+import sys
+import time
+
+# Import Adafruit IO client.
+import Adafruit_IO
+
+
+# Set to your Adafruit IO key.
+ADAFRUIT_IO_KEY = 'YOUR ADAFRUIT IO KEY'
+
+
+# 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 DemoFeed changes...'
+    # Subscribe to changes on a feed named DemoFeed.
+    client.subscribe('DemoFeed')
+
+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 'Feed {0} received new value: {1}'.format(feed_id, payload)
+
+
+# Create an MQTT client instance.
+client = Adafruit_IO.MQTTClient(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()
+
+# Now the program needs to use a client loop function to ensure messages are
+# sent and received.  There are a few options for driving the message loop,
+# depending on what your program needs to do.  
+
+# The first option is to run a thread in the background so you can continue
+# doing things in your program.
+# client.loop_background()
+# Now send new values every 10 seconds.
+print 'Publishing a new message every 10 seconds (press Ctrl-C to quit)...'
+while True:
+    value = random.randint(0, 100)
+    print 'Publishing {0} to DemoFeed.'.format(value)
+    client.publish('DemoFeed', value)
+    time.sleep(10)
+
+# Another option is to pump the message loop yourself by periodically calling
+# the client loop function.  Notice how the loop below changes to call loop
+# continuously while still sending a new message every 10 seconds.  This is a
+# good option if you don't want to or can't have a thread pumping the message
+# loop in the background.
+#last = 0
+#print 'Publishing a new message every 10 seconds (press Ctrl-C to quit)...'
+#while True:
+#   # Explicitly pump the message loop.
+#   client.loop()
+#   # Send a new message every 10 seconds.
+#   if (time.time() - last) >= 10.0:
+#       value = random.randint(0, 100)
+#       print 'Publishing {0} to DemoFeed.'.format(value)
+#       client.publish('DemoFeed', value)
+#       last = time.time()
+
+# The last option is to just call loop_blocking.  This will run a message loop
+# forever, so your program will not get past the loop_blocking call.  This is
+# good for simple programs which only listen to events.  For more complex programs
+# you probably need to have a background thread loop or explicit message loop like
+# the two previous examples above.
+#client.loop_blocking()

test.py renamed to examples/test.py

@@ -1,4 +1,4 @@
-from distutils.core import setup
+from setuptools import setup
 
 setup(
     name='Adafruit_IO',

setup.py

@@ -1,11 +1,16 @@
 Adafruit IO Python Client Test README
 
-To run these tests you must have the pytest module installed.  You can install
-this (assuming you have pip installed) by executing:
-  sudo pip install pytest
+To run the tests you can use python's built in unittest module's auto discovery.
+Do this by running inside this tests directory:
+  python -m unittest discover
 
 Some tests require a valid Adafruit IO account to run, and they key for this
 account is provided in the ADAFRUIT_IO_KEY environment variable.  Make sure to
 set this envirionment variable before running the tests, for example to run all
 the tests with a key execute in this directory:
-  ADAFRUIT_IO_KEY=my_io_key_value py.test
+  ADAFRUIT_IO_KEY=my_io_key_value python -m unittest discover
+
+To add your own tests you are strongly encouraged to build off the test base 
+class provided in base.py.  This class provides a place for common functions
+that don't need to be duplicated across all the tests.  See the existing test
+code for an example of how tests are written and use the base test case.

tests/README.txt

@@ -0,0 +1,20 @@
+# Base testcase class with functions and state available to all tests.
+# Author: Tony DiCola ([email protected])
+import os
+import time
+import unittest
+
+import Adafruit_IO
+
+
+class IOTestCase(unittest.TestCase):
+
+    def get_test_key(self):
+        """Return the AIO key specified in the ADAFRUIT_IO_KEY environment
+        variable, or raise an exception if it doesn't exist.
+        """
+        key = os.environ.get('ADAFRUIT_IO_KEY', None)
+        if key is None:
+            raise RuntimeError("ADAFRUIT_IO_KEY environment variable must be " \
+              "set with valid Adafruit IO key to run this test!")
+        return key

tests/base.py

@@ -1,31 +1,23 @@
-import os
+# Test error responses with REST client.
+# Author: Tony DiCola ([email protected])
 import time
-
-import pytest
+import unittest
 
 import Adafruit_IO
+import base
 
 
-def _get_client():
-  """Return an Adafruit IO client instance configured with the key specified in
-  the ADAFRUIT_IO_KEY environment variable.
-  """
-  key = os.environ.get('ADAFRUIT_IO_KEY', None)
-  if key is None:
-    raise RuntimeError("ADAFRUIT_IO_KEY environment variable must be set with " \
-      "valid Adafruit IO key to run this test!")
-  return Adafruit_IO.Client(key)
-
+class TestErrors(base.IOTestCase):
 
-class TestErrors:    
-  def test_request_error_from_bad_key(self):
-    io = Adafruit_IO.Client("this is a bad key from a test")
-    with pytest.raises(Adafruit_IO.RequestError):
-      io.send("TestStream", 42)
+    def test_request_error_from_bad_key(self):
+        io = Adafruit_IO.Client("this is a bad key from a test")
+        with self.assertRaises(Adafruit_IO.RequestError):
+            io.send("TestStream", 42)
 
-  def test_throttling_error_after_6_requests_in_short_period(self):
-    io = _get_client()
-    with pytest.raises(Adafruit_IO.ThrottlingError):
-      for i in range(6):
-        io.send("TestStream", 42)
-        time.sleep(0.1)  # Small delay to keep from hammering network.
+    @unittest.skip("Throttling test must be run in isolation to prevent other failures.")
+    def test_throttling_error_after_6_requests_in_short_period(self):
+        io = Adafruit_IO.Client(self.get_test_key())
+        with self.assertRaises(Adafruit_IO.ThrottlingError):
+            for i in range(6):
+                io.send("TestStream", 42)
+                time.sleep(0.1)  # Small delay to keep from hammering network.