how to communicate between regular MQTT and websocket MQTT? - python-3.x

Question

I have a main App that initializes fastAPI and uses fastAPI MQTT. Now, this file is running in an event loop and is looking for regular MQTT port.
I have a second app that uses MQTT Websocket and is running in an event loop. Now, I want the two apps to exchange information with each other. How can I make them interchange the information.One is using websocket MQTT and another one is using fast API MQTT. What is the way to make them talk to each other. Here is the
main.py - which runs fastapi and mqtt - regular one.
from fastapi import FastAPI
from fastapi_mqtt import FastMQTT, MQTTConfig
from pydantic import BaseModel
from ipaddress import IPv4Address
import jsonpickle
app = FastAPI()
class Nmap(BaseModel):
host: IPv4Address
portRange: str
class Config:
schema_extra = {
"example" : {
"host": "10.0.2.15",
"portRange": "22-80",
"description": "Scan the port from 22 to 80 of the ip address 10.0.2.15"
}
}
## for docker - compose using mqtt - broker name from docker compose.
## for normal leave that blank to fall off to localhost.
mqtt_config = MQTTConfig(host = "mqtt")
mqtt = FastMQTT(config=mqtt_config)
mqtt.init_app(app)
#mqtt.on_connect()
def connect(client, flags, rc, properties):
mqtt.client.subscribe("/mqtt/toModel/#") # subscribing mqtt topic wildcard- multi-level
print("connected: ", client, flags, rc, properties)
#mqtt.on_message()
async def message(client, topic, payload, qos, properties):
print("received message: ", topic, jsonpickle.decode(payload.decode()), qos, properties)
return 0
#mqtt.on_disconnect()
def disconnect(client, packet, exc=None):
print("Disconnected")
#mqtt.on_subscribe()
def subscribe(client, mid, qos, properties):
print("subscribed", client, mid, qos, properties)
#app.get("/")
async def func():
mqtt.client.publish("/mqtt", "Hello from fastApi")
return {"result": True, "message": "Published"}
#app.post("/scan/{host}")
async def scan_host_port(nmap_details : Nmap):
results = {"got_val" : nmap_details}
print(type(nmap_details))
mqtt.client.publish("/mqtt/fromModel/nmap", jsonpickle.encode(nmap_details))
return results
and here is the websocket based one mqtt.
import paho.mqtt.client as paho
import time
broker="10.0.2.15"
#port= 80
#port=1883
port= 9001
sub_topic="ws/pythonApp"
def on_subscribe(client, userdata, mid, granted_qos): #create function for callback
print("subscribed with qos",granted_qos, "\n")
pass
def on_message(client, userdata, message):
print("message received " ,str(message.payload.decode("utf-8")))
def on_publish(client,userdata,mid): #create function for callback
print("data published mid=",mid, "\n")
pass
def on_disconnect(client, userdata, rc):
print("client disconnected ok")
client= paho.Client("client-socks",transport='websockets') #create client object
#client= paho.Client("control1")
client.on_subscribe = on_subscribe #assign function to callback
client.on_publish = on_publish #assign function to callback
client.on_message = on_message #assign function to callback
client.on_disconnect = on_disconnect
print("connecting to broker ",broker,"on port ",port)
client.connect(broker,port) #establish connection
client.loop_start()
print("subscribing to ",sub_topic)
client.subscribe(sub_topic)
time.sleep(3)
client.publish("ws/jsclient","on") #publish
time.sleep(4)
client.disconnect()

Answer 1

You don't have to do anything, the MQTT broker will bridge both input protocols (native MQTT & MQTT over WebSockets) into the same topic space.
Anything published will be published to any subscribers no matter if they are connected via native MQTT or MQTT over WebSockets.