Add MQTT binary sensor

homeassistant/components/binary_sensor/mqtt.py

@@ -0,0 +1,76 @@
+"""
+homeassistant.components.binary_sensor.mqtt
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Allows to configure a MQTT binary sensor.
+
+For more details about this platform, please refer to the documentation at
+https://home-assistant.io/components/binary_sensor.mqtt/
+"""
+import logging
+from homeassistant.components.binary_sensor import BinarySensorDevice
+import homeassistant.components.mqtt as mqtt
+
+_LOGGER = logging.getLogger(__name__)
+
+DEFAULT_NAME = 'MQTT Binary sensor'
+DEFAULT_QOS = 0
+DEFAULT_PAYLOAD_ON = 'ON'
+DEFAULT_PAYLOAD_OFF = 'OFF'
+
+DEPENDENCIES = ['mqtt']
+
+
+# pylint: disable=unused-argument
+def setup_platform(hass, config, add_devices, discovery_info=None):
+    """ Add MQTT binary sensor. """
+
+    if config.get('state_topic') is None:
+        _LOGGER.error('Missing required variable: state_topic')
+        return False
+
+    add_devices([MqttBinarySensor(
+        hass,
+        config.get('name', DEFAULT_NAME),
+        config.get('state_topic', None),
+        config.get('qos', DEFAULT_QOS),
+        config.get('payload_on', DEFAULT_PAYLOAD_ON),
+        config.get('payload_off', DEFAULT_PAYLOAD_OFF))])
+
+
+# pylint: disable=too-many-arguments, too-many-instance-attributes
+class MqttBinarySensor(BinarySensorDevice):
+    """ Represents a binary sensor that is updated by MQTT. """
+    def __init__(self, hass, name, state_topic, qos, payload_on, payload_off):
+        self._hass = hass
+        self._name = name
+        self._state = False
+        self._state_topic = state_topic
+        self._payload_on = payload_on
+        self._payload_off = payload_off
+        self._qos = qos
+
+        def message_received(topic, payload, qos):
+            """ A new MQTT message has been received. """
+            if payload == self._payload_on:
+                self._state = True
+                self.update_ha_state()
+            elif payload == self._payload_off:
+                self._state = False
+                self.update_ha_state()
+
+        mqtt.subscribe(hass, self._state_topic, message_received, self._qos)
+
+    @property
+    def should_poll(self):
+        """ No polling needed. """
+        return False
+
+    @property
+    def name(self):
+        """ The name of the binary sensor. """
+        return self._name
+
+    @property
+    def is_on(self):
+        """ True if the binary sensor is on. """
+        return self._state