socketpeer

Simple 1:1 messaging via WebRTC Data Channels and WebSockets.

Read this great article.

Features

• concise, Node.js-style API for WebRTC
• simple 1:1 peer connection signalling, pairing, and messaging
• fallback to WebSockets if WebRTC Data Channels are unsupported
• automatic reconnection if peer connections prematurely close

This module works great in the browser with browserify.

NOTE: If you are not using browserify, then use the included standalone file socketpeer.min.js. This exports a SocketPeer function on window.

Installation

To install from npm:

npm install socketpeer

To install the Node dependencies from the git repository:

npm install

Development

To run the browserify watcher (files are output to the build/ directory):

npm run watch

To create the browserify bundles (files are output to the build/ directory):

npm run build

Testing

Set these up locally:

• Sauce Labs
• Travis CI

To run tests locally:

npm run test-local

To run tests in the cloud:

npm test

Client API

peer = new SocketPeer([opts])

Create a new peer WebRTC Data Channel peer connection (only WebRTC if socketFallback is false).

A "data channel" for text/binary communication is always established, because it's cheap and often useful.

If opts is specified, then the default options (shown below) will be overridden.

{
  pairCode: '<random string>',
  socketFallback: true,
  socket: [Object],
  url: 'http://localhost',
  reconnect: true,
  reconnectDelay: 1000,
  timeout: 10000,
  autoconnect: true,
  serveLibrary: true
}

The options do the following:

• pairCode - string used to identify peers
• socketFallback - when true, falls back to WebSockets when WebRTC is unavailable
• socket - custom instance of a WebSocket connection to reuse
• url - URL to WebSocket server
• reconnect - when true, reconnects if peer connection drops
• reconnectDelay - if reconnect is set, how long to (ms) wait before reconnecting
• timeout - how long to wait (ms) before abandoning connection
• autoconnect - when true, automatically connects upon page load
• serveLibrary - when true, serves library at /socketpeer/socketpeer.js

peer.connect()

If reconnect or autoconnect is false, manually start the connection.

peer.send(data)

Send data to the remote peer.

peer.on(event, listener)

Adds a listener to the end of the listeners array for the specified event.

peer.off(event)

Remove listeners for the specified event.

SocketPeer extends Node's EventEmitter. See the docs for the remaining methods.

peer.close()

Destroy and cleanup this peer connection.

Events

peer.on('connect', function () {})

Fired when the peer connection and/or data channel is established.

peer.on('connect_error', function (data) {})

Fired when a connection error occurs.

peer.on('connect_timeout', function (data) {})

Fired when a connection timeout occurs.

peer.on('data', function (data) {})

Received a message from the remote peer.

peer.on('reconnect', function (data) {})

Fired when a reconnection occurs.

peer.on('reconnect_error', function (data) {})

Fired when a reconnection error occurs.

peer.on('reconnect_timeout', function (data) {})

Fired when a reconnection timeout occurs.

peer.on('upgrade', function (data) {})

Fired when a connection is successfully upgraded from WebSocket to RTCDataChannel.

peer.on('upgrade_attempt', function (data) {})

Fired when an upgrade attempt occurs.

peer.on('upgrade_error', function (data) {})

Fired when an upgrade error occurs.

peer.on('downgrade', function (data) {})

Fired when a connection falls back to WebSockets.

peer.on('close', function () {})

Called when the peer connection has closed.

peer.on('busy', function (err) {})

Fired when two clients are already connected using a same pair code. err is an Error object.

peer.on('error', function (err) {})

Fired when an error occurs. err is an Error object.

Server API

peerServer = new SocketPeerServer([opts])

Create a new server for establishing peer connections (i.e., "signalling") and passing WebSocket messages through (if WebRTC Data Channel not supported).

If httpServer is specified, that existing server will be used instead and a ws.Server will be created and attached to it. To use an existing ws.Server for signalling, pass wsServer.

If opts is specified, then the default options (shown below) will be overridden.

{
  allowedOrigins: [Array],
  httpServer: undefined,
  wsServer: undefined,
  peerTimeout: 60000,
  pairCodeValidator: function (pairCode) {}
}

The options do the following:

• allowedOrigins - array of allowed origins (optional)
• peerTimeout - how long to wait before abandoning peer connection (defaults to 6000 ms, 1 minute)
• pairCodeValidator - function that allows custom validation on the pairCode passed from the client (optional)

peerServer.socket

A property that links to the instance of ws.Server.

peerServer.server

A property that links to the instance of http.Server.

peerServer.leave(pairCode)

Breaks both ends of a peer connection (WebSocket or WebRTC).

Licence

MIT Licence

Contributing

Contributions are very welcome!