IOT Mosquitto mqtt how to test on localhost

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You have to add a console.log to your second (the javascript) client to see why it doesn't publishes the Hello properly.

But you can do a typical test with the mosquitto clients:

1) Subscribing to a topic:

mosquitto_sub -d -h localhost -p 1883 -t "myfirst/test"

2) Other client publishes a message content to that topic:

mosquitto_pub -d -h localhost -p 1883 -t "myfirst/test" -m "Hello"

3) All the subscribed clients to this topic will automatically get the message.

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Whisher
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Whisher

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Updated on August 03, 2022

Comments

  • Whisher
    Whisher almost 2 years

    I'm just playing around with mosquitto ans mqtt protocol following the very good video https://www.youtube.com/watch?feature=player_embedded&v=WE7GVIFRV7Q

    trying to test it on my localhost

    in a terminal window I run :

    mosquitto_sub -t "nodeconf/eu" -v
    

    but when I run this snippet:

    var mqtt    = require('mqtt');
    var client  = mqtt.connect();
     client.on('connect', function () {
      client.subscribe('nodeconf/eu');
      client.publish('nodeconf/eu','Hello');
    });
    
    
    client.on('message', function (topic, message) {
      // message is Buffer 
      console.log(message.toString());
      client.end();
    });
    

    I don't see (in my terminal window) any Hello.

    What's wrong, please ?

    BTW I'm also looking for good tutorial and guide on the topic thanks.