81 lines
2.4 KiB
Python
81 lines
2.4 KiB
Python
"""
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homeassistant.components.sensor.mqtt
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Allows to configure a MQTT sensor.
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For more details about this platform, please refer to the documentation at
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https://home-assistant.io/components/sensor.mqtt/
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"""
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import logging
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from homeassistant.const import CONF_VALUE_TEMPLATE, STATE_UNKNOWN
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from homeassistant.helpers.entity import Entity
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from homeassistant.util import template
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import homeassistant.components.mqtt as mqtt
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_LOGGER = logging.getLogger(__name__)
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DEFAULT_NAME = "MQTT Sensor"
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DEFAULT_QOS = 0
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DEPENDENCIES = ['mqtt']
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# pylint: disable=unused-argument
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def setup_platform(hass, config, add_devices_callback, discovery_info=None):
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""" Add MQTT Sensor. """
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if config.get('state_topic') is None:
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_LOGGER.error("Missing required variable: state_topic")
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return False
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add_devices_callback([MqttSensor(
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hass,
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config.get('name', DEFAULT_NAME),
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config.get('state_topic'),
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config.get('qos', DEFAULT_QOS),
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config.get('unit_of_measurement'),
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config.get(CONF_VALUE_TEMPLATE))])
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# pylint: disable=too-many-arguments, too-many-instance-attributes
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class MqttSensor(Entity):
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""" Represents a sensor that can be updated using MQTT. """
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def __init__(self, hass, name, state_topic, qos, unit_of_measurement,
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value_template):
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self._state = STATE_UNKNOWN
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self._hass = hass
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self._name = name
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self._state_topic = state_topic
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self._qos = qos
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self._unit_of_measurement = unit_of_measurement
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def message_received(topic, payload, qos):
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""" A new MQTT message has been received. """
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if value_template is not None:
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payload = template.render_with_possible_json_value(
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hass, value_template, payload)
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self._state = payload
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self.update_ha_state()
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mqtt.subscribe(hass, self._state_topic, message_received, self._qos)
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@property
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def should_poll(self):
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""" No polling needed """
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return False
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@property
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def name(self):
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""" The name of the sensor """
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return self._name
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@property
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def unit_of_measurement(self):
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""" Unit this state is expressed in. """
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return self._unit_of_measurement
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@property
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def state(self):
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""" Returns the state of the entity. """
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return self._state
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