Publish MQTT message via HTTP GET

Question

I need to make a simple proof of concept, having an Arduino or ESP32 with a couple of LEDs than can be turned on/off via browser.

There are a lot of examples about having a small server in the Arduino and accessing it via browser. However for my project I want to use an MQTT broker.

The part where the Arduino updates the LED when a value is changed in the MQTT server is done and works well.

However what I need now it a way of posting a message to the MQTT server just by accessing a website.

Something like: if you open the following link the LED will turn ON: www.mymqttserverdomain.com?LED1=1

score 2 · Answer 1 · answered Aug 28 '21 at 11:18

2

Assuming your broker supports MQTT over WebSockets, just run a MQTT client in the webpage and have it send the messages directly.

There is a Paho JavaScript client and nearly all brokers support WebSockets these days

answered Aug 28 '21 at 11:18

hardillb

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score 0 · Answer 2 · edited May 10 '24 at 15:48

You can, but you must use port 1883 to connect your client with a broker. Here I uploaded a Python code for that

from flask import Flask
import paho.mqtt.client as mqtt
app = Flask(name)
def on_message(client, userdata, message) :
    print("Received message: ", str(message.payload.decode("utf-8","ignore")))
mqttBroker = "broker.emqx.io"
client = mqtt.Client(mqtt.CallbackAPIVersion.VERSION2, "Webpage")
client.on_message = on_message
client.connect(mqttBroker)
client.subscribe("abc")
client.loop_forever()
@app.route('/LED1/<msg>')
def send(msg):
    if msg == '1':
        client.publish("abc", "ON")
    elif msg == '0':
        client.publish("abc", "OFF")
    else:
        pass
    return "ok"
if name == 'main':
    app.run(debug=True)

Note - To turn on your LED1 You have to use this link "<your_gateway>/LED1/1"

Publish MQTT message via HTTP GET

2 Answers2