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mqtt5

jsr

mqtt5 is a client library for the MQTT protocol, written in Typescript for deno and the browser.

mqtt5 supports Mqtt protocol versions 5.0 and 3.1.1.

We have confirmed that deno version 1.44.2 or later works.

Usage

Deno CLI

you can use jsr.

connect mqtt

import { Mqtt, MqttProperties, MqttClient } from "jsr:@ymjacky/mqtt5";

const logger = (msg: string, ...args: unknown[]) => {
  console.log('[Subscriber]', msg, ...args);
};

async function main() {
  const client = new MqttClient({
    url: new URL('mqtt://127.0.0.1:1883'),
    clientId: 'clientA',
    password: 'pass',
    logger: logger,
    clean: true,
    protocolVersion: Mqtt.ProtocolVersion.MQTT_V5,
    keepAlive: 30,
  });

  await client.connect();

  const decoder = new TextDecoder();

  client.on('publish', (event) => {
    const packet = event.detail;
    const receiveMessage = decoder.decode(packet.payload);
    logger(`topic: ${packet.topic}`, `message: ${receiveMessage}`);
  });

  await client.subscribe(['topicA', 'topicB', 'topicC'], Mqtt.QoS.AT_LEAST_ONCE);

  await client.publish('topicA', 'payload', { qos: Mqtt.QoS.AT_MOST_ONCE });
}

main();

connect mqtts (mqtt over TLS)

import { Mqtt, MqttProperties, MqttClient } from "jsr:@ymjacky/mqtt5";

const logger = (msg: string, ...args: unknown[]) => {
  console.log('[Subscriber]', msg, ...args);
};

async function main() {
  const client = new MqttClient({
    url: new URL('mqtts://127.0.0.1:1883'),
    clientId: 'clientA',
    password: 'pass',
    logger: logger,
    clean: true,
    protocolVersion: Mqtt.ProtocolVersion.MQTT_V5,
    keepAlive: 30,
  });

  await client.connect();
}

main();

connect mqtts using CA

import { Mqtt, MqttProperties, MqttClient } from "jsr:@ymjacky/mqtt5";

const logger = (msg: string, ...args: unknown[]) => {
  console.log('[Subscriber]', msg, ...args);
};

async function main() {
  const client = new MqttClient({
    url: new URL('mqtts://127.0.0.1:1883'),
    clientId: 'clientA',
    password: 'pass',
    logger: logger,
    clean: true,
    protocolVersion: Mqtt.ProtocolVersion.MQTT_V5,
    keepAlive: 30,
    caCerts: [Deno.readTextFileSync('xxx/ca.crt.pem')],

  });

  await client.connect();
}

main();

Browser

The following command creates mqtt5.js in the browser directory.

deno task build_ems

Import and use mqtt5.js.

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Test</title>
  </head>
  <body>
    <script type="module">
      import { Mqtt, WebSocketMqttClient } from './mqtt5.mjs';

      const logger = (msg, ...args) =>  {
        console.log('[WS-client]', msg, ...args);
      }

      async function main() {
        const client = new WebSocketMqttClient({
          url: new URL('wss://localhost:18083'),
          clientId: 'someone',
          clean: true,
          logger: logger,
          protocolVersion: Mqtt.ProtocolVersion.MQTT_V5,
          keepAlive: 60,
        });

        await client.connect();
      }
      main();
    </script>
  </body>
</html>

Library Features

The following features are supported.

  1. MQTT V3.1.1
  2. MQTT V5.0
    • Properties
    • Auth Packet
    • ReasonCode
  3. SharedSubscription
    • Enabled by specifying a topic beginning with $share/{sharename}/ in the topicfilter of the subscribe packet.
    • example: client.subscribe('$share/sg1/topicA', Mqtt.QoS.AT_MOST_ONCE);
  4. TopicAlias
    • If the ClientOption’s topicAliasMaximumAboutSend is set to 0 or more, the TopicAlias will be automatically assigned to the Publish packet to be sent.
    • If the ClientOption topicAliasMaximumAboutReceive is set to 0 or higher, the Connect packet will automatically be assigned the topicAliasMaximum property.
  5. ServerRedirect
    • You need to look at the serverReference property of the CONNACK or DISCONNECT packet and reconnect yourself!
  6. Request/Response
    • SUBSCRIBE to the topic marked by the responseInformation property of the CONNACK packet

not supported

The following functions are not supported. (*) marks are features that will be supported in future versions.

  1. (*) persistent session file store
  2. Specifying CA certificates in websocket secure (WSS)
  3. Use of the rejectunauthorized option for TLS connections