fabaccess/fab_access/mqtt_client.py

from paho.mqtt import client as mqtt_client
from config import Config
import json
import random
import string

class MqttHandler:

    @staticmethod
    def setup(msg_handler):
        MqttHandler.msg_handler = msg_handler
        MqttHandler.client = None

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

        def get_random_string(length):
            # choose from all lowercase letter
            letters = string.ascii_lowercase
            result_str = ''.join(random.choice(letters) for i in range(length))
            return(result_str)

        MqttHandler.client = mqtt_client.Client(mqtt_client.CallbackAPIVersion.VERSION1)
        MqttHandler.client.username_pw_set('admin', 'user')
        MqttHandler.client.on_connect = on_connect
        MqttHandler.client.username_pw_set(Config.mqtt_user_name, Config.mqtt_password)
        MqttHandler.client.connect(Config.mqtt_broker, Config.mqtt_port)

    @staticmethod
    def publish(topic, msg):
            result = MqttHandler.client.publish(topic, msg)
            # result: [0, 1]
            status = result[0]
            if status == 0:
                #print(f'Send `{msg}` to topic `{topic}`')
                pass
            else:
                print(f'Failed to send message to topic {topic}')


    @staticmethod
    def subscribe(topic):
        def on_message(client, userdata, msg):
            MqttHandler.msg_handler(msg, client)

        MqttHandler.client.subscribe(topic)
        MqttHandler.client.on_message = on_message

    @staticmethod
    def loop():
        MqttHandler.client.loop_forever()

    @staticmethod
    def switch_plug(PlugID, state):
        MqttHandler.publish(f'/FabLogging/{PlugID}/POWER', 1 if state else 0)
        MqttHandler.publish(f'/cmnd/{PlugID}/POWER', 'On' if state else 'OFF')

    @staticmethod
    def print_to_display(MachineID, status, text):
        message = {
            'Cmd': 'message',
            'MssgID': status,
            'ClrTxt': '',
            'AddnTxt': text,
        }
        MqttHandler.publish(f'/cmnd/reader/{MachineID}', json.dumps(message))