Ok so here is some code below. How do I write an if code block to execute some
commands when I subscribe to the topic: microscope/light_sheet_microscope/UI
and which has a message which is a device type published to it. I want to
execute some code to check if the device has a python file in the currently
directory because each device also relates to a python file. If the file exists
then import the file into the python program else print an error message. If I
need to use on_subscribe callback then tell and show me how the code is to be
written and if another method then also tell me and show me how to write the
code. I really appreciate all the help you can give me because this is really
important for me and I am currently really struggling with MQTT because I need
help with writing MQTT code because I am working on MQTT at work.
import logging
from datetime import timedelta
import time
from thespian.actors import *
from transitions import Machine
import paho.mqtt.client as mqtt
class device(mqtt.Client):
def on_connect(self, mqttc, obj, flags, rc):
if rc == 0:
print("Connected to broker")
else:
print("Connection failed")
mqttc.subscribe("microscope/light_sheet_microscope/UI")
def on_message(self, mqttc, userdata, message):
print("message received " ,str(message.payload.decode("utf-8")))
print("message topic=",message.topic)
print("message qos=",message.qos)
print("message retain flag=",message.retain)
def on_publish(self, mqttc, obj, mid):
print("mid: "+str(mid))
def on_subscribe(self, mqttc, obj, mid, granted_qos):
print("Subscribed: "+str(mid)+" "+str(granted_qos))
def run(self):
self.connect("broker.hivemq.com", 1883, 60)
print("creating new instance laser")
client = device("Device")
client.run()
client.loop_start() #start the loop
device = "laser"
time.sleep(2)
print("Publishing message to topic","microscope/light_sheet_microscope/UI")
client.publish("microscope/light_sheet_microscope/UI",device)
time.sleep(2) # wait
print("subscribing ")
client.subscribe("microscope/light_sheet_microscope/UI")
client.loop_stop() #stop the loop
Thanks
Spencer
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