class PahoIoTClient:
"""
Responsible for connecting to AWS IoT. Handles all connection lifecycle events and attempts to reconnect whenever possible if disconnected. Data is sent to IoT via the method .send_telemetry(TelemetryMessage).
"""
MQTT_QOS_RETRY_INTERVAL_S = 60
KEEP_ALIVE_TIMEOUT_S = 2 * 60
config: IotClientConfig
mqtt_client: Client()
event_listener: IoTEventListener
topic_subscriptions: list
important_paho_messages = [
"Sending PUBLISH (d1", "Connection failed, retrying"
]
def __init__(self, config: IotClientConfig,
event_listener: IoTEventListener):
self.set_config(config=config)
self.event_listener = event_listener
self.mqtt_client = Client(config.client_id)
self.mqtt_client.message_retry_set(self.MQTT_QOS_RETRY_INTERVAL_S)
# self.mqtt_client.tls_set(ca_certs = config.ca_path, certfile = config.certificate_path, keyfile = config.private_key_path)
self.mqtt_client.username_pw_set(username=config.username,
password=config.password)
self.mqtt_client.on_connect = self.on_connected
self.mqtt_client.on_disconnect = self.on_disconnected
self.mqtt_client.on_publish = self.on_message_published
self.mqtt_client.on_message = self.on_message_received
def set_config(self, config: IotClientConfig):
self.config = config
def is_connected(self) -> bool:
return self.mqtt_client.is_connected()
def connect(self):
self.mqtt_client.connect_async(host=self.config.endpoint,
port=self.config.port,
keepalive=self.KEEP_ALIVE_TIMEOUT_S)
self.mqtt_client.loop_start()
def disconnect(self):
self.mqtt_client.disconnect()
self.mqtt_client.loop_stop()
# async def reconnect(self, delay_in_s: int = 5):
# await asyncio.sleep(delay_in_s)
# self.disconnect()
# await asyncio.sleep(delay_in_s)
# self.connect()
def publish(self,
topic: str,
data: str,
qos: int = 1,
reconnect_after_fail: bool = False) -> (int, int):
message_info = self.mqtt_client.publish(topic=topic,
payload=data,
qos=qos)
if message_info.rc is not MQTT_ERR_SUCCESS:
pass
else:
pass
return (message_info.rc, message_info.mid)
def is_response_code_success(self, response_code: int) -> bool:
return response_code is MQTT_ERR_SUCCESS
def initialise_subscriptions_list(self):
self.topic_subscriptions = []
def subscribe(self, subscriptions: list):
for subscription in subscriptions:
if not self.is_topic_subscribed(subscription):
self.topic_subscriptions.append(subscription)
self.mqtt_client.subscribe(topic=self.topic_subscriptions)
def is_topic_subscribed(self, subscription):
for existing_subscription in self.topic_subscriptions:
if subscription[0] == existing_subscription[0]:
return True
return False
def on_connected(self, client, userdata, flags, rc):
self.initialise_subscriptions_list()
if self.event_listener is not None:
self.event_listener.on_iot_connected(iot_client=self)
def on_disconnected(self, client, userdata, rc):
# Clear the list of subscriptions
if self.event_listener is not None:
self.event_listener.on_iot_disconnected(iot_client=self)
def on_message_published(self, client, userdata, mid):
if self.event_listener is not None:
self.event_listener.on_iot_message_published(
self,
message_id=mid,
payload_size=self.payload_sizes.pop("{0}".format(mid), None))
def on_message_received(self, client, userdata, message):
if self.event_listener is not None:
self.event_listener.on_iot_message_received(
iot_client=self, topic=message.topic, payload=message.payload)
