[bug] QOS 2

QOS 2

Hello, I’m going through a somewhat embarrassing situation, I disconnect the Client from the server, send new messages to the topic, but after the client connects, he does not receive the messages. is this normal in QOS 2? I read a very interesting topic: mqtt-essentials-part-6-mqtt-quality-of-service-levels - I’m testing QOS 2

SERVER:

require('dotenv').config();
const mongoose = require('mongoose');
const queryString = require('query-string');
const ClientIo = require('./client-io');
const boardSendRouter = require('./routes/board_send');
const boardRouter = require('./routes/board');
const appSendRouter = require('./routes/app_send');
const appRouter = new appSendRouter();
const url = require('url');
const aedes = require('aedes')();
const mqtt = require('mqtt');
const server = require('net').createServer(aedes.handle);
const port = 1883;


mongoose.connect(process.env.DATABASE_URL, {
    useUnifiedTopology: true,
    useNewUrlParser: true,
    useFindAndModify: false,
});
server.listen(port, function() {
    console.log('Aedes listening on port:', port)
})

aedes.subscribe('board/submit_action', function(packet, cb) {
    try {
        var element = JSON.parse(packet.payload.toString());
        var topic = "board_" + element['id_board'];
        aedes.publish({
            topic: topic,
            payload: packet.payload.toString()
        })
        cb();
    } catch (e) {
        // declarações para manipular quaisquer exceções
        console.log(e); // passa o objeto de exceção para o manipulador de erro
    }
});

CLIENT ARDUINO:

    byte willQoS = 2;
    const char* willTopic = "arduino/status";
    const char* willMessage = "OFF_LINE";
    boolean willRetain = true;
    const char* username = "Placa_1";
    const char* password = "legal";
    boolean cleanSession = false; 

    if (clientMqtt.connect(id_board, username, password, willTopic, willQoS, willRetain, willMessage, cleanSession) { 
      clientMqtt.subscribe("board_5ffcf3e5c18f457afa091c19");
    }

API:

router.get('/', async (req, res, next) => {
    var result = {};
    var result = {
        success: false,
        message: "Invalido"
    };
    // var object = req.body;
    var object = req.query
    if (mongoose.Types.ObjectId.isValid(object.id_board)) {
        if (object.cod != '' && object.cod != '?' && object.cod != undefined) {
            const app_send = new AppSend({
                id_board: object.id_board,
                message: object.cod,
            });
            var save = await app_send.save();
            topic = "board/submit_action";
            var client = mqtt.connect('MYSERVER/mqtt', {
                username: 'Placa_1',
                password: 'legal',
                clientId: 'client_api',
            });
            client.on('connect', () => {
                client.publish(topic, JSON.stringify(save));
                // client.publish("arduino/status", "testekkk");
                client.end();
            });
            client.on('disconnect', () => {
                console.log('disconnect eita');
            });
            client.on('offline', () => {
                console.log('offline eita');
            });
            // client.end();
            // console.log("chegou na acao");
            result['success'] = true;
            result['message'] = "Ação enviada!";
            res.json(result);
            return;
        }
        var promise = await BoardSend.findOne({
            id_board: object.id_board
        }).sort({
            _id: -1
        }).limit(1);
        result = promise ? JSON.parse(promise.message) : {};
        res.json(result);
        return;
    } else {
        res.send(404);
        return;
        // var json = require('./teste-offline.json'); //with path
    }
});

[luan-nvg]

@luan-nvg Could you firstly try an example fully in nodejs or by using another mqtt client? If that is working it means it’s something wrong on the arduino code

I will do the test and give feedback #

[robertsLando]

What you are looking for is the retain flag (on published messages) or the clean flag (on connect). I suggest you to avoid using the clean flag as in most cases retain flag is enough. So set the option retain: true to the messages you send and when the client connects it will receive the last message sent to each topic

---

Daniel

On 27 Jan 2021, at 03:53, luan-nvg [e-mail] wrote:

@robertsLando

when multiple requests are sent via Client nodeJs

has a message that is not coming client.publish(topic, JSON.stringify(params), { qos: 2 });

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