MQTT.js is a client library for the MQTT protocol, written in JavaScript for node.js and the browser.
- Upgrade notes
- Installation
- Example
- Command Line Tools
- API
- Browser
- Weapp
- About QoS
- TypeScript
- Contributing
- License
MQTT.js is an OPEN Open Source Project, see the Contributing section to find out what this means.
v2.0.0 removes support for node v0.8, v0.10 and v0.12, and it is 3x faster in sending
packets. It also removes all the deprecated functionality in v1.0.0,
mainly mqtt.createConnection and mqtt.Server. From v2.0.0,
subscriptions are restored upon reconnection if clean: true.
v1.x.x is now in LTS, and it will keep being supported as long as
there are v0.8, v0.10 and v0.12 users.
v1.0.0 improves the overall architecture of the project, which is now split into three components: MQTT.js keeps the Client, mqtt-connection includes the barebone Connection code for server-side usage, and mqtt-packet includes the protocol parser and generator. The new Client improves performance by a 30% factor, embeds Websocket support (MOWS is now deprecated), and it has a better support for QoS 1 and 2. The previous API is still supported but deprecated, as such, it id not documented in this README.
As a breaking change, the encoding option in the old client is
removed, and now everything is UTF-8 with the exception of the
password in the CONNECT message and payload in the PUBLISH message,
which are Buffer.
Another breaking change is that MQTT.js now defaults to MQTT v3.1.1, so to support old brokers, please read the client options doc.
npm install mqtt --saveFor the sake of simplicity, let's put the subscriber and the publisher in the same file:
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()
})output:
Hello mqtt
If you want to run your own MQTT broker, you can use Mosquitto or Mosca, and launch it. You can also use a test instance: test.mosquitto.org and test.mosca.io are both public.
If you do not want to install a separate broker, you can try using the mqtt-connection.
to use MQTT.js in the browser see the browserify section
If you want to use the new async-await functionality in JavaScript, or just prefer using Promises instead of callbacks, async-mqtt is a wrapper over MQTT.js which uses promises instead of callbacks when possible.
MQTT.js bundles a command to interact with a broker. In order to have it available on your path, you should install MQTT.js globally:
npm install mqtt -gThen, on one terminal
mqtt sub -t 'hello' -h 'test.mosquitto.org' -v
On another
mqtt pub -t 'hello' -h 'test.mosquitto.org' -m 'from MQTT.js'
See mqtt help <command> for the command help.
mqtt.connect()mqtt.Client()mqtt.Client#publish()mqtt.Client#subscribe()mqtt.Client#unsubscribe()mqtt.Client#end()mqtt.Client#removeOutgoingMessage()mqtt.Client#reconnect()mqtt.Client#handleMessage()mqtt.Client#connectedmqtt.Client#reconnectingmqtt.Client#getLastMessageId()mqtt.Store()mqtt.Store#put()mqtt.Store#del()mqtt.Store#createStream()mqtt.Store#close()
Connects to the broker specified by the given url and options and returns a Client.
The URL can be on the following protocols: 'mqtt', 'mqtts', 'tcp',
'tls', 'ws', 'wss'. The URL can also be an object as returned by
URL.parse(),
in that case the two objects are merged, i.e. you can pass a single
object with both the URL and the connect options.
You can also specify a servers options with content: [{ host: 'localhost', port: 1883 }, ... ], in that case that array is iterated
at every connect.
For all MQTT-related options, see the Client constructor.
The Client class wraps a client connection to an
MQTT broker over an arbitrary transport method (TCP, TLS,
WebSocket, ecc).
Client automatically handles the following:
- Regular server pings
- QoS flow
- Automatic reconnections
- Start publishing before being connected
The arguments are:
streamBuilderis a function that returns a subclass of theStreamclass that supports theconnectevent. Typically anet.Socket.optionsis the client connection options (see: the connect packet). Defaults:wsOptions: is the WebSocket connection options. Default is{}. It's specific for WebSockets. For possible options have a look at: https://github.com/websockets/ws/blob/master/doc/ws.md.keepalive:60seconds, set to0to disablereschedulePings: reschedule ping messages after sending packets (defaulttrue)clientId:'mqttjs_' + Math.random().toString(16).substr(2, 8)protocolId:'MQTT'protocolVersion:4clean:true, set to false to receive QoS 1 and 2 messages while offlinereconnectPeriod:1000milliseconds, interval between two reconnectionsconnectTimeout:30 * 1000milliseconds, time to wait before a CONNACK is receivedusername: the username required by your broker, if anypassword: the password required by your broker, if anyincomingStore: a Store for the incoming packetsoutgoingStore: a Store for the outgoing packetsqueueQoSZero: if connection is broken, queue outgoing QoS zero messages (defaulttrue)will: a message that will sent by the broker automatically when the client disconnect badly. The format is:topic: the topic to publishpayload: the message to publishqos: the QoSretain: the retain flag
transformWsUrl: optional(url, options, client) => urlfunction For ws/wss protocols only. Can be used to implement signing urls which upon reconnect can have become expired.resubscribe: if connection is broken and reconnects, subscribed topics are automatically subscribed again (defaulttrue)
In case mqtts (mqtt over tls) is required, the options object is
passed through to
tls.connect().
If you are using a self-signed certificate, pass the rejectUnauthorized: false option.
Beware that you are exposing yourself to man in the middle attacks, so it is a configuration
that is not recommended for production environments.
If you are connecting to a broker that supports only MQTT 3.1 (not 3.1.1 compliant), you should pass these additional options:
{
protocolId: 'MQIsdp',
protocolVersion: 3
}This is confirmed on RabbitMQ 3.2.4, and on Mosquitto < 1.3. Mosquitto version 1.3 and 1.4 works fine without those.
function (connack) {}
Emitted on successful (re)connection (i.e. connack rc=0).
connackreceived connack packet. Whencleanconnection option isfalseand server has a previous session forclientIdconnection option, thenconnack.sessionPresentflag istrue. When that is the case, you may rely on stored session and prefer not to send subscribe commands for the client.
function () {}
Emitted when a reconnect starts.
function () {}
Emitted after a disconnection.
function () {}
Emitted when the client goes offline.
function (error) {}
Emitted when the client cannot connect (i.e. connack rc != 0) or when a parsing error occurs.
function (topic, message, packet) {}
Emitted when the client receives a publish packet
topictopic of the received packetmessagepayload of the received packetpacketreceived packet, as defined in mqtt-packet
function (packet) {}
Emitted when the client sends any packet. This includes .published() packets as well as packets used by MQTT for managing subscriptions and connections
packetreceived packet, as defined in mqtt-packet
function (packet) {}
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
packetreceived packet, as defined in mqtt-packet
Publish a message to a topic
topicis the topic to publish to,Stringmessageis the message to publish,BufferorStringoptionsis the options to publish with, including:qosQoS level,Number, default0retainretain flag,Boolean, defaultfalsedupmark as duplicate flag,Boolean, defaultfalse
callback-function (err), fired when the QoS handling completes, or at the next tick if QoS 0. An error occurs if client is disconnecting.
Subscribe to a topic or topics
topicis aStringtopic to subscribe to or anArrayof topics to subscribe to. It can also be an object, it has as object keys the topic name and as value the QoS, like{'test1': 0, 'test2': 1}. MQTTtopicwildcard characters are supported (+- for single level and#- for multi level)optionsis the options to subscribe with, including:qosqos subscription level, default 0
callback-function (err, granted)callback fired on suback where:erra subscription error or an error that occurs when client is disconnectinggrantedis an array of{topic, qos}where:topicis a subscribed to topicqosis the granted qos level on it
Unsubscribe from a topic or topics
topicis aStringtopic or an array of topics to unsubscribe fromcallback-function (err), fired on unsuback. An error occurs if client is disconnecting.
Close the client, accepts the following options:
force: passing it to true will close the client right away, without waiting for the in-flight messages to be acked. This parameter is optional.cb: will be called when the client is closed. This parameter is optional.
Remove a message from the outgoingStore. The outgoing callback will be called withe Error('Message removed') if the message is removed.
After this function is called, the messageId is released and becomes reusable.
mid: The messageId of the message in the outgoingStore.
Connect again using the same options as connect()
Handle messages with backpressure support, one at a time.
Override at will, but always call callback, or the client
will hang.
Boolean : set to true if the client is connected. false otherwise.
Number : get last message id. This is for sent messages only.
Boolean : set to true if the client is trying to reconnect to the server. false otherwise.
In-memory implementation of the message store.
optionsis the store options:clean:true, clean inflight messages when close is called (defaulttrue)
Other implementations of mqtt.Store:
- mqtt-level-store which uses Level-browserify to store the inflight data, making it usable both in Node and the Browser.
- mqtt-nedbb-store which uses nedb to store the inflight data.
- mqtt-localforage-store which uses localForage to store the inflight data, making it usable in the Browser without browserify.
Adds a packet to the store, a packet is
anything that has a messageId property.
The callback is called when the packet has been stored.
Creates a stream with all the packets in the store.
Removes a packet from the store, a packet is
anything that has a messageId property.
The callback is called when the packet has been removed.
Closes the Store.
The MQTT.js bundle is available through http://unpkg.com, specifically at https://unpkg.com/mqtt/dist/mqtt.min.js. See http://unpkg.com for the full documentation on version ranges.
Surport Weixin App. See Doc.
var mqtt = require('mqtt')
var client = mqtt.connect('wxs://test.mosquitto.org')import { connect } from 'mqtt';
const client = connect('wxs://test.mosquitto.org');In order to use MQTT.js as a browserify module you can either require it in your browserify bundles or build it as a stand alone module. The exported module is AMD/CommonJs compatible and it will add an object in the global space.
npm install -g browserify // install browserify
cd node_modules/mqtt
npm install . // install dev dependencies
browserify mqtt.js -s mqtt > browserMqtt.js // require mqtt in your client-side appJust like browserify, export MQTT.js as library. The exported module would be var mqtt = xxx and it will add an object in the global space. You could also export module in other formats (AMD/CommonJS/others) by setting output.libraryTarget in webpack configuration.
npm install -g webpack // install webpack
cd node_modules/mqtt
npm install . // install dev dependencies
webpack mqtt.js ./browserMqtt.js --output-library mqttyou can then use mqtt.js in the browser with the same api than node's one.
<html>
<head>
<title>test Ws mqtt.js</title>
</head>
<body>
<script src="./browserMqtt.js"></script>
<script>
var client = mqtt.connect() // you add a ws:// url here
client.subscribe("mqtt/demo")
client.on("message", function (topic, payload) {
alert([topic, payload].join(": "))
client.end()
})
client.publish("mqtt/demo", "hello world!")
</script>
</body>
</html>Your broker should accept websocket connection (see MQTT over Websockets to setup Mosca).
If you need to sign an url, for example for AWS IoT,
then you can pass in a transformWsUrl function to the mqtt.connect() options
This is needed because signed urls have an expiry and eventually upon reconnects, a new signed url needs to be created:
// This module doesn't actually exist, just an example
var awsIotUrlSigner = require('awsIotUrlSigner')
mqtt.connect('wss://a2ukbzaqo9vbpb.iot.ap-southeast-1.amazonaws.com/mqtt', {
transformWsUrl: function (url, options, client) {
// It's possible to inspect some state on options(pre parsed url components)
// and the client (reconnect state etc)
return awsIotUrlSigner(url)
}
})
// Now every time a new WebSocket connection is opened (hopefully not that
// often) we get a freshly signed urlHere is how QoS works:
- QoS 0 : received at most once : The packet is sent, and that's it. There is no validation about whether it has been received.
- QoS 1 : received at least once : The packet is sent and stored as long as the client has not received a confirmation from the server. MQTT ensures that it will be received, but there can be duplicates.
- QoS 2 : received exactly once : Same as QoS 1 but there is no duplicates.
About data consumption, obviously, QoS 2 > QoS 1 > QoS 0, if that's a concern to you.
This repo bundles TypeScript definition files for use in TypeScript projects and to support tools that can read .d.ts files.
Before you can begin using these TypeScript definitions with your project, you need to make sure your project meets a few of these requirements:
- TypeScript >= 2.1
- Set tsconfig.json:
{"compilerOptions" : {"moduleResolution" : "node"}, ...} - Includes the TypeScript definitions for node. You can use npm to install this by typing the following into a terminal window:
npm install --save-dev @types/node
MQTT.js is an OPEN Open Source Project. This means that:
Individuals making significant and valuable contributions are given commit-access to the project to contribute as they see fit. This project is more like an open wiki than a standard guarded open source project.
See the CONTRIBUTING.md file for more details.
MQTT.js is only possible due to the excellent work of the following contributors:
| Adam Rudd | GitHub/adamvr | Twitter/@adam_vr |
|---|---|---|
| Matteo Collina | GitHub/mcollina | Twitter/@matteocollina |
| Maxime Agor | GitHub/4rzael | Twitter/@4rzael |
MIT