MQTT

Server

• Username+password required, anonymous connections not allowed.
• mqtt:// - not available
• mqtts:// - server mqtt.renert.housegordon.com tcp port 8883
• ws:// - not available (websockets over HTTP, not encrypted)
• wss:// - server mqtt.renert.housegordon.com tcp port 433 path /mqtt.
  i.e: wss://USERNAME:PW@mqtt.renert.housegordon.com:443/mqtt

Command Line

apt-get install mosquitto-clients

mosquitto_pub -L mqtts://USERNAME:PW@mqtt.renert.housegordon.com/mytopic -m MyMessage

mosquitto_sub -L mqtts://USERNAME:PW@mqtt.renert.housegordon.com/mytopic

Python 3

Publish

from paho.mqtt import client as mqtt_client
import sys

client_id = 'My-Python-Client-ID'
broker = 'mqtt.renert.housegordon.com'
port = 8883
username = 'USERNAME'
pw = 'PW'

client = mqtt_client.Client(client_id=client_id,
                            callback_api_version=mqtt_client.CallbackAPIVersion.VERSION2)
client.tls_set()
client.username_pw_set(username,pw)

res = client.connect(broker,port)
if res != 0:
    sys.exit("Failed to connect to MQTT server")

res = client.publish("mytopic","my-python-message")
if res[0] != 0:
    sys.exit("Failed to publish message")

Subscribe

from paho.mqtt import client as mqtt_client
import sys

client_id = 'My-Python-Client-ID'
broker = 'mqtt.renert.housegordon.com'
port = 8883
username = 'USERNAME'
pw = 'PW'
topic = "mytopic"

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


def on_message(client, userdata, msg):
    print(f"Received `{msg.payload.decode()}` from `{msg.topic}` topic")

## Connect
client = mqtt_client.Client(client_id=client_id,
                            callback_api_version=mqtt_client.CallbackAPIVersion.VERSION2)
client.tls_set()
client.username_pw_set(username, pw)
client.on_connect = on_connect
client.connect(broker, port)

## Subscribe
client.subscribe(topic)
client.on_message = on_message

## Receive loop
print("Connected to MQTT broker - waiting for messages with topic: ", topic)
client.loop_forever()

MicroPython (e.g. ESP32)

Publish

import network
import ssl
import time
import umqtt.simple as MQTTClient

## Wifi Setup
wifi_ssid = "SSID"
wifi_pw   = "WIFI-PW"

sta_if = network.WLAN(network.STA_IF)
sta_if.active(True)
sta_if.connect(wifi_ssid, wifi_pw)
while True:
    time.sleep(0.5)
    if sta_if.isconnected():
        break
    print("Wifi not connected yet, sleeping and re-trying...")

## MQTT
client_id = "My-MicroPython-Client"
broker = "mqtt.renert.housegordon.com"
port = 8883
username = "USERNAME"
pw = "PW"
topic = "mytopic"
message = "fooBAZ"

# Ugly Hack Alert: the 'ssl' parameter points to the SSL Module directly.
# It seems to just work. No clue if the SSL certificate is actually verified.
client = MQTTClient(client_id, broker, port, username, pw, ssl=ssl)
res = client.connect()
if res == 0:
    client.publish(topic, message)
else:
    print("ERROR Connecting to MQTT: ", res)

Subscribe

import network
import ssl
import time
import umqtt.simple as MQTTClient

## Wifi Setup
wifi_ssid = "SSID"
wifi_pw   = "WIFI-PW"

sta_if = network.WLAN(network.STA_IF)
sta_if.active(True)
sta_if.connect(wifi_ssid, wifi_pw)
while True:
    time.sleep(0.5)
    if sta_if.isconnected():
        break
    print("Wifi not connected yet, sleeping and re-trying...")

## MQTT
client_id = "My-MicroPython-Client"
broker = "mqtt.renert.housegordon.com"
port = 8883
username = "USERNAME"
pw = "PW"
topic = "mytopic"
message = "fooBAZ"


def on_message(topic,message):
    #NOTE:
    # topic and message will be BYTEs, not STRs
    print("Got Message! topic = ", topic, " message = ", message)

# Ugly Hack Alert: the 'ssl' parameter points to the SSL Module directly.
# It seems to just work. No clue if the SSL certificate is actually verified.
client = MQTTClient(client_id, broker, port, username, pw, ssl=ssl)
res = client.connect()
if res != 0:
    sys.exit("ERROR Connecting to MQTT: ", res)




client.subscribe(topic)
client.set_callback(on_message)

# "wait_msg()" will block until one message is received (and AFTER 'on_message' is called).
# use "check_msg()" for non-blocking equivalent.
client.wait_msg()

Javascript (Browser)

  <script src="https://unpkg.com/mqtt/dist/mqtt.min.js"></script>
  <script>

// Create an MQTT client instance
const options = {
  clean: true,
  connectTimeout: 4000,
  clientId: 'My-JS-Client',
  username: 'USERNAME',
  password: 'PASSWORD',
}
let topic = "mytopic" ;
let message = "fooBar9" ;

// if the MQTT.js library wasn't loaded, this will be undefined
console.log("MQTT library = ", mqtt );

let client = mqtt.connect('wss://mqtt.renert.housegordon.com/mqtt', options );

// Client will be a valid MQTT object, even if the connection failed or hasn't completed yet
console.log("MQTT Client = ", client);

client.on('connect', function () {
	//TODO:
	// "connect" will not be called if there's a connection error,
	// consider using a timeout to detect connection errors.

	console.log('Connected to MQTT')

	console.log("Subscribing to a topic");
	client.subscribe(topic);
	
	console.log("publishing message...");
	client.publish(topic, message);
});

client.on('message', function (topic, message) {
  // The message parameter is a UInt8Array Buffer,
  console.log("Got Message! topic = ", topic, " message = ", message) ;

  // if you know the message is a string, decode it like so (might fail with UTF-8 characters):
  var str = String.fromCharCode.apply(null, message);
  console.log("Message as string: ", str);
});

//If/when you need to:
//client.end();

  </script>