core/homeassistant/components/mqtt/discovery.py

63 lines
1.8 KiB
Python

"""
Support for MQTT discovery.
For more details about this component, please refer to the documentation at
https://home-assistant.io/components/mqtt/#discovery
"""
import asyncio
import json
import logging
import re
import homeassistant.components.mqtt as mqtt
from homeassistant.components.mqtt import DOMAIN
from homeassistant.helpers.discovery import async_load_platform
from homeassistant.const import CONF_PLATFORM
from homeassistant.components.mqtt import CONF_STATE_TOPIC
_LOGGER = logging.getLogger(__name__)
TOPIC_MATCHER = re.compile(
r'(?P<prefix_topic>\w+)/(?P<component>\w+)/(?P<object_id>\w+)/config')
SUPPORTED_COMPONENTS = ['binary_sensor', 'sensor']
@asyncio.coroutine
def async_start(hass, discovery_topic, hass_config):
"""Initialization of MQTT Discovery."""
# pylint: disable=unused-variable
@asyncio.coroutine
def async_device_message_received(topic, payload, qos):
"""Process the received message."""
match = TOPIC_MATCHER.match(topic)
if not match:
return
prefix_topic, component, object_id = match.groups()
try:
payload = json.loads(payload)
except ValueError:
_LOGGER.warning("Unable to parse JSON %s: %s", object_id, payload)
return
if component not in SUPPORTED_COMPONENTS:
_LOGGER.warning("Component %s is not supported", component)
return
payload = dict(payload)
payload[CONF_PLATFORM] = 'mqtt'
if CONF_STATE_TOPIC not in payload:
payload[CONF_STATE_TOPIC] = '{}/{}/{}/state'.format(
discovery_topic, component, object_id)
yield from async_load_platform(
hass, component, DOMAIN, payload, hass_config)
yield from mqtt.async_subscribe(
hass, discovery_topic + '/#', async_device_message_received, 0)
return True