99 lines
3.2 KiB
Python
99 lines
3.2 KiB
Python
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#!/usr/bin/python
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"""
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Author: Vertigo Designs, Ryan Summers
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Robert Jördens
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Description: Provides an API for controlling Miniconf devices over MQTT.
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"""
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import asyncio
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import json
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import logging
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import uuid
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from gmqtt import Client as MqttClient
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LOGGER = logging.getLogger(__name__)
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class MiniconfException(Exception):
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""" Generic exceptions generated by Miniconf. """
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class Miniconf:
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"""An asynchronous API for controlling Miniconf devices using MQTT."""
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@classmethod
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async def create(cls, prefix, broker):
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"""Create a connection to the broker and a Miniconf device using it."""
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client = MqttClient(client_id='')
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await client.connect(broker)
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return cls(client, prefix)
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def __init__(self, client, prefix):
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"""Constructor.
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Args:
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client: A connected MQTT5 client.
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prefix: The MQTT toptic prefix of the device to control.
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"""
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self.request_id = 0
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self.client = client
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self.prefix = prefix
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self.inflight = {}
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self.client.on_message = self._handle_response
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self.response_topic = f'{prefix}/response/{uuid.uuid1().hex}'
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self.client.subscribe(self.response_topic)
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def _handle_response(self, _client, topic, payload, _qos, properties):
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"""Callback function for when messages are received over MQTT.
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Args:
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_client: The MQTT client.
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topic: The topic that the message was received on.
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payload: The payload of the message.
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_qos: The quality-of-service level of the received packet
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properties: A dictionary of properties associated with the message.
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"""
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if topic == self.response_topic:
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# Extract request_id corrleation data from the properties
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request_id = int.from_bytes(
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properties['correlation_data'][0], 'big')
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self.inflight[request_id].set_result(json.loads(payload))
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del self.inflight[request_id]
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else:
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LOGGER.warning('Unexpected message on "%s"', topic)
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async def command(self, path, value, retain=True):
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"""Write the provided data to the specified path.
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Args:
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path: The path to write the message to.
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value: The value to write to the path.
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retain: Retain the MQTT message changing the setting
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by the broker.
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Returns:
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The response to the command as a dictionary.
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"""
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topic = f'{self.prefix}/settings/{path}'
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fut = asyncio.get_running_loop().create_future()
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# Assign unique correlation data for response dispatch
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assert self.request_id not in self.inflight
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self.inflight[self.request_id] = fut
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correlation_data = self.request_id.to_bytes(4, 'big')
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self.request_id += 1
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payload = json.dumps(value)
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LOGGER.info('Sending "%s" to "%s"', value, topic)
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self.client.publish(
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topic, payload=payload, qos=0, retain=retain,
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response_topic=self.response_topic,
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correlation_data=correlation_data)
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result = await fut
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if result['code'] != 0:
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raise MiniconfException(result['msg'])
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