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MQTT.md

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MQTT

This module is a native module for the MQTT protocol, which is compatible with the MQTT.js.

Example

var mqtt = require('mqtt');
var client  = mqtt.connect('mqtt://test.mosquitto.org');

client.on('connect', function () {
  client.subscribe('presence');
  client.publish('presence', 'Hello mqtt');
});

client.on('message', function (topic, message) {
  // message is Buffer
  console.log(message.toString());
  client.end();
});

Class: MqttClient

new MqttClient(endpoint, options)

  • endpoint {String} The uri of what your MQTT service at.
  • options {Object} The options:
    • keepalive {Number} 60 seconds, set to 0 to disable
    • clientId {String} 'mqttjs_' + Math.random().toString(16).substr(2, 8)
    • protocolId {String} MQTT
    • protocolVersion {String} 4
    • clean {Boolean} true, set to false to receive QoS 1 and 2 messages while offline
    • reconnectPeriod {Number} 1000 milliseconds, interval between two reconnections
    • connectTimeout {Number} 30 * 1000 milliseconds, time to wait before a CONNACK is received
    • username {String} the username required by your broker, if any
    • password {String} the password required by your broker, if any

Creates a new client of endpoint.

client.connect()

Connects the specified before url by MQTT.

Event 'connect'

Emitted on successful (re)connection (i.e. connack rc=0).

Event 'reconnect'

Emitted when a reconnect starts.

Event 'offline'

Emitted when the client goes offline.

Event 'error'

  • err {Error} the error returned.

Emitted when the client cannot connect (i.e. connack rc != 0) or when a parsing error occurs.

Event 'message'

  • topic {String} topic of the received packet.
  • message {String} payload of the received packet.

Emitted when the client receives a publish packet.

Event 'packetsend'

Emitted when the client sends any packet. This includes .published() packets as well as packets used by MQTT for managing subscriptions and connections.

Event 'packetreceive'

Emitted when the client receives any packet. This includes packets from subscribed topics as well as packets used by MQTT for managing subscriptions and connections.

client.publish(topic, message[, options[, callback]])

  • topic {String} topic to publish
  • message {String|Buffer} message to publish
  • options {Object} options to publish with, including:
    • qos {Number} QoS level, default 0
    • dup {Boolean} mark as duplicate flag, default false
    • retain {Boolean} retain flag, default false
  • callback fired when the QoS handling completes, or at the next tick if QoS 0. An error occurs if client is disconnecting.

Publish a message to a topic.

client.subscribe(topic[, options[, callback]])

  • topic {String} topic to publish
  • options {Object} options to publish with, including:
    • qos {Number} QoS level, default 0
  • callback callback fired on suback.

Subscribe to a topic.

Not support on topics array or object.

client.unsubscribe(topic[, callback])

  • topic {String} topic to publish
  • callback callback fired on suback.

Unsubscribe from a topic.

client.end([force[, callback]])

  • force {Boolean} passing it to true will close the client right away.
  • callback {Function} will be called when the client is closed. This parameter is optional.

Close the client.

client.disconnect([err, [, callback]])

This method is deprecated.

  • err {Error} throw an error before disconnect. This parameter is optional.
  • callback {Function} will be called when the client is closed. This parameter is optional.

Disconnect the client right away The client can safety be unref after call this method.

client.reconnect()

Disconnect current connection(if connected) and connect again using the same options as connect().

For more detailed, please see MQTT.js Readme.