Update MQTT component and add example

.gitignore

@@ -7,6 +7,7 @@ homeassistant/components/frontend/www_static/polymer/bower_components/*
 config/custom_components/*
 !config/custom_components/example.py
 !config/custom_components/hello_world.py
+!config/custom_components/mqtt_example.py
 
 # Hide sublime text stuff
 *.sublime-project

config/custom_components/mqtt_example.py

@@ -0,0 +1,60 @@
+"""
+custom_components.mqtt_example
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Shows how to communicate with MQTT. Follows a topic on MQTT and updates the
+state of an entity to the last message received on that topic.
+
+Also offers a service 'set_state' that will publish a message on the topic that
+will be passed via MQTT to our message received listener. Call the service with
+example payload {"new_state": "some new state"}.
+
+Configuration:
+
+To use the mqtt_example component you will need to add the following to your
+config/configuration.yaml
+
+mqtt_example:
+  topic: home-assistant/mqtt_example
+
+"""
+import homeassistant.loader as loader
+
+# The domain of your component. Should be equal to the name of your component
+DOMAIN = "mqtt_example"
+
+# List of component names (string) your component depends upon
+DEPENDENCIES = ['mqtt']
+
+
+CONF_TOPIC = 'topic'
+DEFAULT_TOPIC = 'home-assistant/mqtt_example'
+
+
+def setup(hass, config):
+    """ Setup our mqtt_example component. """
+    mqtt = loader.get_component('mqtt')
+    topic = config[DOMAIN].get('topic', DEFAULT_TOPIC)
+    entity_id = 'mqtt_example.last_message'
+
+    # Listen to a message on MQTT
+
+    def message_received(topic, payload, qos):
+        """ A new MQTT message has been received. """
+        hass.states.set(entity_id, payload)
+
+    mqtt.subscribe(hass, topic, message_received)
+
+    hass.states.set(entity_id, 'No messages')
+
+    # Service to publish a message on MQTT
+
+    def set_state_service(call):
+        """ Service to send a message. """
+        mqtt.publish(hass, topic, call.data.get('new_state'))
+
+    # Register our service with Home Assistant
+    hass.services.register(DOMAIN, 'set_state', set_state_service)
+
+    # return boolean to indicate that initialization was successful
+    return True

homeassistant/components/mqtt.py

@@ -11,12 +11,16 @@
 To use MQTT you will need to add something like the following to your
 config/configuration.yaml.
 
+mqtt:
+  broker: 127.0.0.1
+
+Or, if you want more options:
+
 mqtt:
   broker: 127.0.0.1
   port: 1883
-  topic: home-assistant
+  client_id: home-assistant-1
   keepalive: 60
-  qos: 0
 
 Variables:
 
@@ -28,18 +32,14 @@
 *Optional
 The network port to connect to. Default is 1883.
 
-topic
+client_id
 *Optional
-The MQTT topic to subscribe to. Default is home-assistant.
+Client ID that Home Assistant will use. Has to be unique on the server.
+Default is a random generated one.
 
 keepalive
 *Optional
-The keep alive in seconds for this client, e.g. 60.
-
-qos
-*Optional
-Quality of service level to use for the subscription.
-0, 1, or 2, defaults to 0.
+The keep alive in seconds for this client. Default is 60.
 """
 import logging
 import socket
@@ -55,7 +55,6 @@
 
 MQTT_CLIENT = None
 
-DEFAULT_TOPIC = 'home-assistant'
 DEFAULT_PORT = 1883
 DEFAULT_KEEPALIVE = 60
 DEFAULT_QOS = 0
@@ -68,24 +67,36 @@
 
 CONF_BROKER = 'broker'
 CONF_PORT = 'port'
-CONF_TOPIC = 'topic'
+CONF_CLIENT_ID = 'client_id'
 CONF_KEEPALIVE = 'keepalive'
-CONF_QOS = 'qos'
 
 ATTR_QOS = 'qos'
 ATTR_TOPIC = 'topic'
-ATTR_SUBTOPIC = 'subtopic'
 ATTR_PAYLOAD = 'payload'
 
 
-def publish(hass, payload, subtopic=None):
+def publish(hass, topic, payload):
     """ Send an MQTT message. """
-    data = {ATTR_PAYLOAD: payload}
-    if subtopic is not None:
-        data[ATTR_SUBTOPIC] = subtopic
+    data = {
+        ATTR_TOPIC: topic,
+        ATTR_PAYLOAD: payload,
+    }
     hass.services.call(DOMAIN, SERVICE_PUBLISH, data)
 
 
+def subscribe(hass, topic, callback, qos=0):
+    """ Subscribe to a topic. """
+    def mqtt_topic_subscriber(event):
+        """ Subscribes to a specific MQTT topic. """
+        if event.data[ATTR_TOPIC] == topic:
+            callback(topic, event.data[ATTR_PAYLOAD], event.data[ATTR_QOS])
+
+    hass.bus.listen(EVENT_MQTT_MESSAGE_RECEIVED, mqtt_topic_subscriber)
+
+    if topic not in MQTT_CLIENT.topics:
+        MQTT_CLIENT.subscribe(topic, qos)
+
+
 def setup(hass, config):
     """ Get the MQTT protocol service. """
 
@@ -96,13 +107,12 @@ def setup(hass, config):
 
     broker = conf[CONF_BROKER]
     port = util.convert(conf.get(CONF_PORT), int, DEFAULT_PORT)
-    topic = util.convert(conf.get(CONF_TOPIC), str, DEFAULT_TOPIC)
+    client_id = util.convert(conf.get(CONF_CLIENT_ID), str)
     keepalive = util.convert(conf.get(CONF_KEEPALIVE), int, DEFAULT_KEEPALIVE)
-    qos = util.convert(conf.get(CONF_QOS), int, DEFAULT_QOS)
 
     global MQTT_CLIENT
     try:
-        MQTT_CLIENT = MQTT(hass, broker, port, keepalive, qos)
+        MQTT_CLIENT = MQTT(hass, broker, port, client_id, keepalive)
     except socket.error:
         _LOGGER.exception("Can't connect to the broker. "
                           "Please check your settings and the broker "
@@ -115,19 +125,16 @@ def stop_mqtt(event):
 
     def start_mqtt(event):
         """ Launch MQTT component when Home Assistant starts up. """
-        MQTT_CLIENT.subscribe('{}/#'.format(topic))
         MQTT_CLIENT.start()
         hass.bus.listen_once(EVENT_HOMEASSISTANT_STOP, stop_mqtt)
 
     def publish_service(call):
         """ Handle MQTT publish service calls. """
+        msg_topic = call.data.get(ATTR_TOPIC)
         payload = call.data.get(ATTR_PAYLOAD)
-        if payload is None:
+        if msg_topic is None or payload is None:
             return
-        subtopic = call.data.get(ATTR_SUBTOPIC)
-        msg_topic = '{}/{}'.format(topic, subtopic) if subtopic else topic
-
-        MQTT_CLIENT.publish(msg_topic, payload=payload)
+        MQTT_CLIENT.publish(msg_topic, payload)
 
     hass.bus.listen_once(EVENT_HOMEASSISTANT_START, start_mqtt)
 
@@ -138,49 +145,78 @@ def publish_service(call):
 
 # This is based on one of the paho-mqtt examples:
 # http://git.eclipse.org/c/paho/org.eclipse.paho.mqtt.python.git/tree/examples/sub-class.py
-# pylint: disable=too-many-arguments, invalid-name
 class MQTT(object):
     """ Implements messaging service for MQTT. """
-    def __init__(self, hass, broker, port, keepalive, qos):
+    def __init__(self, hass, broker, port, client_id, keepalive):
         import paho.mqtt.client as mqtt
 
         self.hass = hass
-        self._qos = qos
+        self._progress = {}
+        self.topics = {}
 
-        self._mqttc = mqtt.Client()
-        self._mqttc.on_message = self.mqtt_on_message
-        self._mqttc.connect(broker, port, keepalive)
-
-    def mqtt_on_message(self, mqttc, obj, msg):
-        """ Message callback """
-        if '/' in msg.topic:
-            msg_topic, msg_subtopic = msg.topic.split('/', 1)
+        if client_id is None:
+            self._mqttc = mqtt.Client()
         else:
-            msg_topic, msg_subtopic = msg.topic, ''
-
-        self.hass.bus.fire(EVENT_MQTT_MESSAGE_RECEIVED, {
-            ATTR_TOPIC: msg_topic,
-            ATTR_SUBTOPIC: msg_subtopic,
-            ATTR_QOS: msg.qos,
-            ATTR_PAYLOAD: msg.payload.decode('utf-8'),
-        })
+            self._mqttc = mqtt.Client(client_id)
+        self._mqttc.on_subscribe = self._mqtt_on_subscribe
+        self._mqttc.on_unsubscribe = self._mqtt_on_unsubscribe
+        self._mqttc.on_connect = self._mqtt_on_connect
+        self._mqttc.on_message = self._mqtt_on_message
+        self._mqttc.connect(broker, port, keepalive)
 
-    def subscribe(self, topic):
-        """ Subscribe to a topic. """
-        self._mqttc.subscribe(topic, qos=self._qos)
+    def publish(self, topic, payload):
+        """ Publish a MQTT message. """
+        self._mqttc.publish(topic, payload)
 
     def unsubscribe(self, topic):
         """ Unsubscribe from topic. """
-        self._mqttc.unsubscribe(topic)
+        result, mid = self._mqttc.unsubscribe(topic)
+        self._progress[mid] = topic
+
+    def start(self):
+        """ Run the MQTT client. """
+        self._mqttc.loop_start()
 
     def stop(self):
         """ Stop the MQTT client. """
         self._mqttc.loop_stop()
 
-    def start(self):
-        """ Run the MQTT client. """
-        self._mqttc.loop_start()
+    def subscribe(self, topic, qos):
+        """ Subscribe to a topic. """
+        if topic in self.topics:
+            return
+        result, mid = self._mqttc.subscribe(topic, qos)
+        self._progress[mid] = topic
+        self.topics[topic] = None
+
+    def _mqtt_on_connect(self, mqttc, obj, flags, rc):
+        """ On connect, resubscribe to all topics we were subscribed to. """
+        old_topics = self.topics
+        self._progress = {}
+        self.topics = {}
+        for topic, qos in old_topics.items():
+            # qos is None if we were in process of subscribing
+            if qos is not None:
+                self._mqttc.subscribe(topic, qos)
+
+    def _mqtt_on_subscribe(self, mqttc, obj, mid, granted_qos):
+        """ Called when subscribe succesfull. """
+        topic = self._progress.pop(mid, None)
+        if topic is None:
+            return
+        self.topics[topic] = granted_qos
 
-    def publish(self, topic, payload):
-        """ Publish a MQTT message. """
-        self._mqttc.publish(topic, payload)
+    def _mqtt_on_unsubscribe(self, mqttc, obj, mid, granted_qos):
+        """ Called when subscribe succesfull. """
+        topic = self._progress.pop(mid, None)
+        if topic is None:
+            return
+        self.topics.pop(topic, None)
+
+    def _mqtt_on_message(self, mqttc, obj, msg):
+        """ Message callback """
+        self.hass.bus.fire(EVENT_MQTT_MESSAGE_RECEIVED, {
+            ATTR_TOPIC: msg.topic,
+            ATTR_QOS: msg.qos,
+            ATTR_PAYLOAD: msg.payload.decode('utf-8'),
+        })