317 lines
11 KiB
Python
317 lines
11 KiB
Python
# The MIT License (MIT)
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#
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# Copyright (c) 2019 Brent Rubell for Adafruit Industries
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#
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# Permission is hereby granted, free of charge, to any person obtaining a copy
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# of this software and associated documentation files (the "Software"), to deal
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# in the Software without restriction, including without limitation the rights
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# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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# copies of the Software, and to permit persons to whom the Software is
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# furnished to do so, subject to the following conditions:
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#
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# The above copyright notice and this permission notice shall be included in
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# all copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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# THE SOFTWARE.
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"""
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`adafruit_aws_iot`
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================================================================================
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Amazon AWS IoT MQTT Client for CircuitPython
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* Author(s): Brent Rubell
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Implementation Notes
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--------------------
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**Hardware:**
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**Software and Dependencies:**
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* Adafruit CircuitPython firmware for the supported boards:
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https://github.com/adafruit/circuitpython/releases
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"""
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import json
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from adafruit_minimqtt import MMQTTException
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__version__ = "0.0.0-auto.0"
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__repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_AWS_IOT.git"
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class AWS_IOT_ERROR(Exception):
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"""Exception raised on MQTT API return-code errors."""
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# pylint: disable=unnecessary-pass
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pass
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class MQTT_CLIENT:
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"""Client for interacting with Amazon AWS IoT MQTT API.
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:param MiniMQTT mmqttclient: Pre-configured MiniMQTT Client object.
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:param int keep_alive: Optional Keep-alive timer interval, in seconds.
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Provided interval must be 30 <= keep_alive <= 1200.
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"""
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def __init__(self, mmqttclient, keep_alive=30):
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if "MQTT" in str(type(mmqttclient)):
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self.client = mmqttclient
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else:
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raise TypeError(
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"This class requires a preconfigured MiniMQTT object, \
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please create one."
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)
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# Verify MiniMQTT client object configuration
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try:
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self.cid = self.client.client_id
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assert (
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self.cid[0] != "$"
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), "Client ID can not start with restricted client ID prefix $."
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except:
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raise TypeError(
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"You must provide MiniMQTT with your AWS IoT Device's Identifier \
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as the Client ID."
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)
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# Shadow-interaction topic
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self.shadow_topic = "$aws/things/{}/shadow".format(self.cid)
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# keep_alive timer must be between 30 <= keep alive interval <= 1200 seconds
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# https://docs.aws.amazon.com/general/latest/gr/aws_service_limits.html
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assert (
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30 <= keep_alive <= 1200
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), "Keep_Alive timer \
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interval must be between 30 and 1200 seconds"
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self.keep_alive = keep_alive
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# User-defined MQTT callback methods must be init'd to None
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self.on_connect = None
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self.on_disconnect = None
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self.on_message = None
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self.on_subscribe = None
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self.on_unsubscribe = None
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# Connect MiniMQTT callback handlers
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self.client.on_connect = self._on_connect_mqtt
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self.client.on_disconnect = self._on_disconnect_mqtt
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self.client.on_message = self._on_message_mqtt
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self.client.on_subscribe = self._on_subscribe_mqtt
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self.client.on_unsubscribe = self._on_unsubscribe_mqtt
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self.connected_to_aws = False
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def __enter__(self):
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return self
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def __exit__(self, exception_type, exception_value, traceback):
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self.disconnect()
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@property
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def is_connected(self):
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"""Returns if MQTT_CLIENT is connected to AWS IoT MQTT Broker
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"""
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return self.connected_to_aws
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def disconnect(self):
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"""Disconnects from Amazon AWS IoT MQTT Broker and de-initializes the MiniMQTT Client.
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"""
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try:
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self.client.disconnect()
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except MMQTTException as error:
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raise AWS_IOT_ERROR("Error disconnecting with AWS IoT: ", error)
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self.connected_to_aws = False
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# Reset user-defined callback methods to None
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self.on_connect = None
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self.on_disconnect = None
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self.on_message = None
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self.on_subscribe = None
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self.on_unsubscribe = None
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self.client.deinit()
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def reconnect(self):
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"""Reconnects to the AWS IoT MQTT Broker
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"""
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try:
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self.client.reconnect()
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except MMQTTException as error:
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raise AWS_IOT_ERROR("Error re-connecting to AWS IoT:", error)
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def connect(self, clean_session=True):
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"""Connects to Amazon AWS IoT MQTT Broker with Client ID.
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:param bool clean_session: Establishes a clean session with AWS broker.
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"""
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try:
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self.client.connect(clean_session)
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except MMQTTException as error:
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raise AWS_IOT_ERROR("Error connecting to AWS IoT: ", error)
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self.connected_to_aws = True
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# MiniMQTT Callback Handlers
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# pylint: disable=not-callable, unused-argument
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def _on_connect_mqtt(self, client, userdata, flag, ret_code):
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"""Runs when code calls on_connect.
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:param MiniMQTT client: MiniMQTT client object.
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:param str user_data: User data from broker
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:param int flag: QoS flag from broker.
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:param int ret_code: Return code from broker.
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"""
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self.connected_to_aws = True
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# Call the on_connect callback if defined in code
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if self.on_connect is not None:
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self.on_connect(self, userdata, flag, ret_code)
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# pylint: disable=not-callable, unused-argument
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def _on_disconnect_mqtt(self, client, userdata, flag, ret_code):
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"""Runs when code calls on_disconnect.
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:param MiniMQTT client: MiniMQTT client object.
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:param str user_data: User data from broker
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:param int flag: QoS flag from broker.
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:param int ret_code: Return code from broker.
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"""
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self.connected_to_aws = False
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# Call the on_connect callback if defined in code
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if self.on_connect is not None:
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self.on_connect(self, userdata, flag, ret_code)
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# pylint: disable=not-callable
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def _on_message_mqtt(self, client, topic, payload):
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"""Runs when the client calls on_message.
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:param MiniMQTT client: MiniMQTT client object.
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:param str topic: MQTT broker topic.
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:param str payload: Payload returned by MQTT broker topic
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"""
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if self.on_message is not None:
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self.on_message(self, topic, payload)
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# pylint: disable=not-callable
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def _on_subscribe_mqtt(self, client, user_data, topic, qos):
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"""Runs when the client calls on_subscribe.
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:param MiniMQTT client: MiniMQTT client object.
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:param str user_data: User data from broker
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:param str topic: Desired MQTT topic.
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param int qos: Quality of service level for topic, from broker.
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"""
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if self.on_subscribe is not None:
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self.on_subscribe(self, user_data, topic, qos)
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# pylint: disable=not-callable
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def _on_unsubscribe_mqtt(self, client, user_data, topic, pid):
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"""Runs when the client calls on_unsubscribe.
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"""
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if self.on_unsubscribe is not None:
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self.on_unsubscribe(self, user_data, topic, pid)
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# MiniMQTT Network Control Flow
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def loop(self):
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""" Starts a synchronous message loop which maintains connection with AWS IoT.
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Must be called within the keep_alive timeout specified to init.
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This method does not handle network connection/disconnection.
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Example of "pumping" an AWS IoT message loop:
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..code-block::python
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while True:
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aws_iot.loop()
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"""
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if self.connected_to_aws:
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self.client.loop()
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def loop_forever(self):
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"""Begins a blocking, asynchronous message loop.
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This method handles network connection/disconnection.
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"""
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if self.connected_to_aws:
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self.client.loop_forever()
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@staticmethod
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def validate_topic(topic):
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"""Validates if user-provided pub/sub topics adhere to AWS Service Limits.
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https://docs.aws.amazon.com/general/latest/gr/aws_service_limits.html
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:param str topic: Desired topic to validate
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"""
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assert hasattr(topic, "split"), "Topic must be a string"
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assert len(topic) < 256, "Topic must be less than 256 bytes!"
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assert len(topic.split("/")) <= 9, "Topics are limited to 7 forward slashes."
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# MiniMQTT Pub/Sub Methods, for usage with AWS IoT
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def subscribe(self, topic, qos=1):
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"""Subscribes to an AWS IoT Topic.
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:param str topic: MQTT topic to subscribe to.
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:param int qos: Desired topic subscription's quality-of-service.
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"""
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assert qos < 2, "AWS IoT does not support subscribing with QoS 2."
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self.validate_topic(topic)
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self.client.subscribe(topic, qos)
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def publish(self, topic, payload, qos=1):
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"""Publishes to a AWS IoT Topic.
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:param str topic: MQTT topic to publish to.
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:param str payload: Data to publish to topic.
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:param int payload: Data to publish to topic.
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:param float payload: Data to publish to topic.
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:param json payload: JSON-formatted data to publish to topic.
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:param int qos: Quality of service level for publishing.
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"""
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assert qos < 2, "AWS IoT does not support publishing with QoS 2."
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self.validate_topic(topic)
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if isinstance(payload, int or float):
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payload = str(payload)
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self.client.publish(topic, payload, qos=qos)
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# AWS IoT Device Shadow Service
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def shadow_get_subscribe(self, qos=1):
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"""Subscribes to device's shadow get response.
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:param int qos: Optional quality of service level.
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"""
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self.client.subscribe(self.shadow_topic + "/get/#", qos)
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def shadow_subscribe(self, qos=1):
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"""Subscribes to all notifications on the device's shadow update topic.
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:param int qos: Optional quality of service level.
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"""
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self.client.subscribe(self.shadow_topic + "/update/#", qos)
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def shadow_update(self, document):
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"""Publishes a request state document to update the device's shadow.
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:param json state_document: JSON-formatted state document.
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"""
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self.client.publish(self.shadow_topic + "/update", document)
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def shadow_get(self):
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"""Publishes an empty message to shadow get topic to get the device's shadow.
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"""
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self.client.publish(
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self.shadow_topic + "/get", json.dumps({"message": "ignore"})
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)
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def shadow_delete(self):
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"""Publishes an empty message to the shadow delete topic to delete a device's shadow
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"""
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self.client.publish(
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self.shadow_topic + "/delete", json.dumps({"message": "delete"})
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)
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