Using Python to communicate with OpenRemote using MQTT (paho-MQTT)

Agents, Protocols and APIs
1

Hi all,

I want to share a short guide a student has made while she was working on a project using OpenRemote. All credits go to Nina Taken and her team for creating a wonderful project (video will come soon) and this guide.

MQTT-OpenRemote.pdf (488.3 KB)

They connected an ESP32 with sensors to monitor soil and air conditions for plants to OpenRemote. She used paho-MQTT as MQTT client in Python to connect to our broker. I hope it will be helpful for some of you!

If you have any questions I will direct them to her, or ask her to join our forum.

Don

4 Likes
2

Hey Don,

I guess there is missing some Code for the ESP.

ESP32 can micropython, but it is not that usual, and the example in the doc don‘t provide micropython for an ESP.

3

Hi Denis,

Thanks for letting me know. I adjusted the title a little bit to focus more on the Python side of it.

Don

1 Like
4

Used this example, and I had problem with clientMQTT.tls_set(certify.where()) ()
CERTIFICATE_VERIFY_FAILED

May be it was because I use virtualbox+ubuntuserver with OR and trying to connect from PC+windows over local net.
So, if you have same problems, you can try this code (visual studio code + python3.10):

import paho.mqtt.client as mqtt
import time
import certifi
import ssl
import json

def on_connect(client, userdata, flags, rc):
if rc == 0:
print(“Connected to broker”)
global Connected #Use global variable
Connected = True #Signal connection
else:
print(“Connection failed”)

def on_publish(client, userdata, result):
print(f’Data published. Data: {attribute_value}')
pass

def on_message(client, userdata, message):
msg = json.loads(message.payload.decode(“utf-8”))
id = msg[“attributeState”][“ref”][“id”]
att_name = msg[“attributeState”][“ref”][“name”]
att_value = msg[“attributeState”][“value”]
print(f’Message received. Asset ID: {id}. Attribute name: {att_name}. Attribute value: {att_value}')

Connected = False
username = ‘master:mqttuser’
secret = ‘UwNbCqV_YOUR_SECRET_DYDvzP5Z’
host = ‘salmon.local’
port = 8883
clientID = ‘WQTTwrt’
assetID = ‘7PaWocH_YOUR_THING_pq93h’
attributeWr = ‘writeAttribute’
attribute_value = 10

attributeRd = ‘subscribeAttribute’

clientMQTT = mqtt.Client(clientID)
clientMQTT.username_pw_set(username, password = secret)

//# the key steps here
context = ssl.SSLContext(ssl.PROTOCOL_TLSv1_2)
//# if you do not want to check the cert hostname, skip it
//# context.check_hostname = False
clientMQTT.tls_set_context(context)

clientMQTT.on_connect = on_connect
clientMQTT.on_publish = on_publish
clientMQTT.on_message = on_message
clientMQTT.connect(host, port=port)
clientMQTT.loop_start()

while Connected != True:
time.sleep(0.1)

while attribute_value <=42 :
clientMQTT.publish(f"master/{clientID}/writeattributevalue/{attributeWr}/{assetID}“, attribute_value)
clientMQTT.subscribe(f"master/{clientID}/attribute/{attributeRd}/{assetID}”)

time.sleep(5)
attribute_value += 1

clientMQTT.disconnect()
clientMQTT.loop_stop()

image
image1085×817 67.1 KB

Here:
//# the key steps here
context = ssl.SSLContext(ssl.PROTOCOL_TLSv1_2)
//# if you do not want to check the cert hostname, skip it
//# context.check_hostname = False

you need to remove //

3 Likes
5

Hi Don,
I read the document shared by you and I tried to connect Open remote using Python script. but i have doubt In document they write in python code “netLab.openremote.app” as a Host. but here I am using “https://localhost/manager/#/assets/false/xxxxxxxxxxxxxxxx” as host. so i think for that i am not able to connect with openremote. so what should I write here as host.

Thank you

6

If your docker runs locally, then just type in: localhost