university-final-iot-backend/app/mod_devices/mqtt_client.py

78 lines
2.1 KiB
Python

import sys
import json
from flask_mqtt import Mqtt
from .models import Recording
from app import db, app
mqtt = Mqtt()
# Mqtt setup
def setup_mqtt(app):
mqtt.init_app(app)
mqtt.client.on_message = handle_mqtt_message
mqtt.client.on_subscribe = handle_subscribe
print('MQTT client initialized')
def tear_down_mqtt():
mqtt.unsubscribe_all()
if hasattr(mqtt, 'client') and mqtt.client is not None:
mqtt.client.disconnect()
print('MQTT client destroyed')
@mqtt.on_connect()
def handle_connect(client, userdata, flags, rc):
print('MQTT client connected')
mqtt.subscribe('device/+')
@mqtt.on_disconnect()
def handle_disconnect():
print('MQTT client disconnected')
def handle_subscribe(client, userdata, mid, granted_qos):
print('MQTT client subscribed')
def handle_mqtt_message(client, userdata, message):
print("Received message!")
print("Topic: " + message.topic)
print("Payload: " + message.payload.decode())
try:
# If type is JSON
recording = parse_json_message(message.topic, message.payload.decode())
with app.app_context():
recording.save()
except ValueError:
print("ERROR!")
error_type, error_instance, traceback = sys.exc_info()
print("Type: " + str(error_type))
print("Instance: " + str(error_instance))
return
def parse_json_message(topic, payload) -> Recording:
try:
json_msg = json.loads(payload)
device_id = get_device_id(topic)
return Recording(device_id=device_id,
record_type=json_msg["record_type"],
record_value=json_msg["record_value"],
recorded_at=json_msg["recorded_at"],
raw_json=json_msg)
except KeyError:
error_type, error_instance, traceback = sys.exc_info()
raise ValueError("JSON parsing failed! Key error: "
+ str(error_instance))
def get_device_id(topic) -> int:
device_token, device_id = topic.split("/")
if device_token == "device":
return int(device_id)
else:
raise ValueError("Topic is in invalid format")