fabaccess/fab_access/mqtt_helper.py

from paho.mqtt import client as mqtt_client

import config


def on_connect(client, userdata, flags, rc):
    if rc == 0:
        print("Connected to MQTT Broker!")
    else:
        raise Exception("Failed to connect, return code %d\n", rc)


class MQTTHelper():
    def __init__(self, client_name: str, username: str, password: str, broker: str, port: int):
        client = mqtt_client.Client(client_name)
        if username and password:
            client.username_pw_set(username, password)
        else:
            print("Connecting to MQTT without credentials")
        client.on_connect = on_connect
        try:
            client.connect(broker, port)
        except Exception as e:
            raise Exception(f"Error connecting to MQTT {broker}:{port}") from e
        self.client = client

    def subscribe(self, topic: str, handler):
        self.client.subscribe(topic)
        self.client.on_message = handler

    def loop_forever(self):
        self.client.loop_forever()