This repository contains JavaScript client for both NodeJS and the Browser for Emitter (see also on Emitter GitHub). Emitter is an open-source real-time communication service for connecting online devices. At its core, emitter.io is a distributed, scalable and fault-tolerant publish-subscribe messaging platform based on MQTT protocol and featuring message storage.
Emitter for NodeJS:
npm install emitter-io --save
Emitter for the Browser:
// connect to emitter.io and get the client
var client = emitter.connect(); // or: require('emitter-io') on NodeJS
// once we're connected, subscribe to the 'chat' channel
client.subscribe({
key: "<channel key>",
channel: "chat"
});
// on every message, print it out
client.on('message', function(msg){
console.log( msg.asString() );
});
// publish a message to the chat channel
client.publish({
key: "<channel key>",
channel: "chat/my_name",
message: "hello, emitter!"
});
connect()
Emitter()
Emitter#publish()
Emitter#subscribe()
Emitter#unsubscribe()
Emitter#keygen()
Emitter#disconnect()
EmitterMessage()
EmitterMessage#asString()
EmitterMessage#asBinary()
EmitterMessage#asObject()
Connects to the emitter api broker specified by the given url and options and returns an Emitter instance. 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.
The Emitter
class wraps a client connection to an emitter.io MQTT broker over an arbitrary transport method (TCP, TLS, WebSocket, ecc). It automatically handles the following by with help of MQTT.js client:
- Regular server pings
- QoS flow
- Automatic reconnections
- Start publishing before being connected
function(connack) {}
Emitted on successful (re)connection (i.e. connack rc=0).
connack
received connack packet. Whenclean
connection option isfalse
and server has a previous session forclientId
connection option, thenconnack.sessionPresent
flag istrue
. When that is the case, you may rely on stored session and prefer not to send subscribe commands for the client.
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(keyJson) {}
Emitted when the client generate a key to a channel using Emitter#keygen()
function.
function(message) {}
Emitted when the client receives a message packet. The message object will be of EmitterMessage class, encapsulating the channel and the payload.
Publish a message to a channel
key
is security key to use for the operation,String
channel
is the channel string to publish to,String
message
is the message to publish,Buffer
orString
Subscribes to a channel
key
is security key to use for the operation,String
channel
is the channel string to subscribe to,String
Unsubscribes from a channel
key
is security key to use for the operation,String
channel
is the channel string to unsubscribe from,String
Sends a key generation request to the server.
key
is master/secret key to use for the operation,String
channel
is the channel string to generate a key for,String
type
the type of the key to generate. Possible options includer
for read-only,w
for write-only andrw
for read-write keys,String
ttl
is the time-to-live of the key, in seconds.
Requests the presence for a particular channel.
key
is master/secret key to use for the operation,String
channel
is the channel string to generate a key for,String
status
whether the current state should be retrieved or notchanges
whether the future changes should be received or not
Retrieves information about the underlying client connection.
Disconnects from the remote broker
The EmitterMessage
class wraps a message received from the broker. It contains several properties:
channel
is channel the message was published to,String
binary
is the buffer associated with the payload,Buffer
Returns the payload as a utf-8 String
.
Returns the payload as the Buffer
.
Returns the payload as JSON-deserialized Object
.
The MIT License (MIT) Copyright (c) 2016 Misakai Ltd.