Add MQTT Switch

homeassistant/components/switch/mqtt.py

@@ -0,0 +1,146 @@
+# -*- coding: utf-8 -*-
+"""
+homeassistant.components.switch.mqtt
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Allows to configure a MQTT switch.
+
+In an ideal scenario, the MQTT device will have a state topic to publish state changes.
+If these messages are published with RETAIN flag, the MQTT switch will receive 
+an instant state update after subscription and will start with correct state. Otherwise, 
+the initial state of the switch will be false/off.
+
+When a state topic is not available, the switch will work in an optimistic mode.
+In this mode, the MQTT switch will immediately change state after every command.
+Otherwise, the switch will wait for state confirmation from device (message from state_topic).
+
+Optimistic mode can be forced, even if state topic is available. 
+Try to enable it, if experiencing incorrect switch operation.
+
+
+Configuration:
+
+switch:
+  platform: mqtt
+  name: "Bedroom Switch"
+  state_topic: "home/bedroom/switch1"
+  command_topic: "home/bedroom/switch1/set"
+  payload_on: "ON"
+  payload_off: "OFF"
+  optimistic: false
+
+Variables:
+
+name
+*Optional
+The name of the switch. Default is 'MQTT Switch'.
+
+state_topic
+*Optional
+The MQTT topic subscribed to receive state updates. 
+If not specified, optimistic mode will be forced.
+
+command_topic
+*Required
+The MQTT topic to publish commands to change the switch state.
+
+payload_on
+*Optional
+The payload that represents enabled state. Default is "ON".
+
+payload_off
+*Optional
+The payload that represents disabled state. Default is "OFF".
+
+optimistic
+*Optional
+Flag that defines if switch works in optimistic mode. Default is false.
+
+"""
+
+import logging
+import homeassistant.components.mqtt as mqtt
+from homeassistant.components.switch import SwitchDevice
+
+_LOGGER = logging.getLogger(__name__)
+
+DEFAULT_NAME = "MQTT Switch"
+DEFAULT_PAYLOAD_ON = "ON"
+DEFAULT_PAYLOAD_OFF = "OFF"
+DEFAULT_OPTIMISTIC = False
+
+DEPENDENCIES = ['mqtt']
+
+# pylint: disable=unused-argument
+def setup_platform(hass, config, add_devices_callback, discovery_info=None):
+    """ Add MQTT Switch """
+
+    if config.get('command_topic') is None:
+        _LOGGER.error("Missing required variable: command_topic")
+        return False
+    
+    add_devices_callback([MqttSwitch(
+        hass,
+        config.get('name', DEFAULT_NAME),
+        config.get('state_topic'),
+        config.get('command_topic'),
+        config.get('payload_on', DEFAULT_PAYLOAD_ON),
+        config.get('payload_off', DEFAULT_PAYLOAD_OFF),
+        config.get('optimistic', DEFAULT_OPTIMISTIC))])
+
+class MqttSwitch(SwitchDevice):
+    """ Represents a switch that can be togggled using MQTT """
+    def __init__(self, hass, name, state_topic, command_topic, payload_on, payload_off, optimistic):
+        self._state = False        
+        self._hass = hass
+        self._name = name
+        self._state_topic = state_topic
+        self._command_topic = command_topic
+        self._payload_on = payload_on
+        self._payload_off = payload_off
+        self._optimistic = optimistic
+            
+        def message_received(topic, payload, qos):
+            if (payload == self._payload_on):
+                self._state = True
+                self.update_ha_state()
+            elif (payload == self._payload_off):
+                self._state = False
+                self.update_ha_state()
+
+        if self._state_topic is None:
+            """ force optimistic mode """
+            self._optimistic = True
+        else:
+            """ subscribe the state_topic """
+            mqtt.subscribe(hass, self._state_topic, message_received)
+
+    @property
+    def should_poll(self):
+        """ No polling needed """
+        return False
+
+    @property
+    def name(self):
+        """ The name of the switch """
+        return self._name
+
+    @property
+    def is_on(self):
+        """ True if device is on. """
+        return self._state
+
+    def turn_on(self, **kwargs):
+        """ Turn the device on. """
+        mqtt.publish(self.hass, self._command_topic, self._payload_on)
+        if self._optimistic:
+            """ optimistically assume that switch has changed state """
+            self._state = True
+            self.update_ha_state()
+
+    def turn_off(self, **kwargs):
+        """ Turn the device off. """
+        mqtt.publish(self.hass, self._command_topic, self._payload_off)
+        if self._optimistic:
+            """ optimistically assume that switch has changed state """
+            self._state = False
+            self.update_ha_state()