projektarbeit_duelger_waldhauser_caliskan/software/backend/main.py

"""
created by caliskan at 19.04.2023

This file contains the main script for the backend server of smart garden project
It has the task to be a bridge between the frontend and robot.
It also contains a database with the current plant data
Used protocol for interaction: mqtt (paho-mqtt module)
"""

# imports
import paho.mqtt.client as mqtt
from defines import MQTT_BROKER_LOCAL, MQTT_BROKER_GLOBAL
from plantdatabase import PlantDataBase
from data_handling_functions import data_handler

# inits
mydatabase = PlantDataBase()
mydatabase.create_table()


def on_message(client: mqtt.Client, userdata, message):
    """
    This method gets called, if a subscribed channel gets a new message.
    Message gets forwarded to the data handler
    :param client: mqtt client object
    :param userdata:
    :param message: received message object
    :return: None
    """
    print(type(message))
    print(f'message received! {message.topic}')
    data_handler(client, message, mydatabase)


def on_connect(client: mqtt.Client, userdata, flags, rc):
    """
    This method gets called, when it connects to a mqtt broker.
    It is used to subscribe to the specific topics
    :param client: mqtt client object
    :param userdata:
    :param flags:
    :param rc: connection flag
    :return:
    """
    if rc == 0:
        print("connected")

        # TOPIC SUBSCRIPTIONS

        # From Robot:
        client.subscribe('Robot/Data/SensorData')
        client.subscribe('Robot/Data/Position')
        client.subscribe('Robot/Data/Battery')
        # client.subscribe('Robot/Data/Picture')

        # From FrontEnd:
        client.subscribe('BackEnd/Action/Drive')
        client.subscribe('BackEnd/Action/GetPosition')
        client.subscribe('BackEnd/Action/GetBattery')
        client.subscribe('BackEnd/Action/GetAllData')
        # END TOPIC SUBSCRIPTIONS
    else:
        print("connection failed")


def main():
    client = mqtt.Client()
    client.on_connect = on_connect
    client.on_message = on_message
    client.connect(MQTT_BROKER_GLOBAL)
    client.loop_forever()


if __name__ == "__main__":
    main()