SocketPeer

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

Read this great walk-through article.

View a live demo of a project using SocketPeer! See the (project's source code).

Features

• concise, Node.js-style API for WebRTC peer-to-peer connections
• simple 1:1 peer connection signalling, pairing, and messaging
• fallback WebSocket support if WebRTC Data Channels are unsupported
• automatic reconnection if peer connections prematurely close
• exports as a UMD module, so the library works everywhere (i.e., using Browserify, webpack, or included by a <script> tag in any modern browser)

Usage

If you are requiring socketpeer as a Node package using npm/yarn + Browserify/webpack, install the socketpeer package from your project directory like so:

npm install socketpeer --save

NOTE: If you are not using Browserify/webpack, then use the included standalone file, socketpeer.min.js, which exports to window a function called SocketPeer.

Read this great walk-through article.

View a live demo of a project using SocketPeer! See the (project's source code).

Additionally, here's some sample code to quickly get you started using socketpeer:

var socketpeer = require('socketpeer');

var peer = new SocketPeer({
  pairCode: 'yolo',
  url: 'http://localhost:3000/socketpeer/'
});

peer.on('connect', function () {
  console.log('peer connected');
});

peer.on('connect_timeout', function () {
  console.error('connection timed out (after %s ms)', peer.timeout);
});

peer.on('data', function (data) {
  console.log('data received:', data);
});

peer.on('rtc.signal', function () {
  console.log('WebRTC signalling');
});

peer.on('peer.found', function (data) {
  console.log('peer found:', data.initiator);
  peer.send('hello');
});

peer.on('upgrade', function () {
  console.log('successfully upgraded WebSocket ⇒ to WebRTC peer connection');
  peer.send('upgraded');
});

peer.on('upgrade_attempt', function () {
  console.log('attempting to upgrade WebSocket ⇒ to WebRTC peer connection (attempt number: %d)', peer._connections.rtc.attempt);
});

peer.on('downgrade', function () {
  console.log('downgraded WebRTC peer connection ⇒ to WebSocket connection');
});

peer.on('warning', function (data) {
  console.error('warning:', data.message);
});

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

For more examples, refer to the demo directory.

Development

Installation

1. If you haven't already, install Node.js (which includes npm).

2. Clone this repository (cvan/socketpeer):

   git clone git@github.com:cvan/socketpeer.git

3. In the root directory of the cloned repository of the project, install the Node dependencies:

   cd cvan/socketpeer/
   npm install

4. When all the latest dependencies are installed, from the socketpeer/ directory, run these commands (each in a separate terminal tab):

   # Start the server for local development (includes server live-reloading).
   npm start
   
   # Run the Browserify watcher (files are written to the `build/` directory).
   npm run watch

   This will generate a non-minified version of the library and will run a watcher which recompiles the socketpeer library when local changes are saved to disk.

Commands (npm scripts) for local development

• npm run build (or npm run dist) – builds the distribution-ready files for SocketPeer (i.e., socketpeer.js, socketpeer.min.js), to the root project directory.
• npm start (or npm run dev) – builds the development version of the library and runs a file watcher.
• npm run test – runs the tests.
• npm run test-local – runs the tests in a continuous-watch mode (useful for local, test-driven development).
• npm run release – deploy the current project directory as a module to npm as the socketpeer package.

Distribution

To build the Browserify bundles:

npm run build

Two files will be written to this project's root directory:

• socketpeer.js – the development/debug-purposed, unminified version of SocketPeer (UMD-compatible).
• socketpeer.min.js – the production-ready, minified version of SocketPeer (UMD-compatible).

Tests

Refer to these docs for setting up continuous-integration testing locally:

• Sauce Labs
• Travis CI

To run the tests intended for a local environment:

npm run test-local

To run the tests in "the cloud" (e.g., Sauce Labs, Travis CI):

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,
  debug: false
}

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 wait (in milliseconds) before reconnecting
• timeout - how long to wait (in milliseconds) before abandoning connection
• autoconnect - when true, automatically connects upon page load
• serveLibrary - when true, serves library at /socketpeer/socketpeer.js
• debug - when true, logs debugging information to the console

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/whitelisted origins (optional)
• peerTimeout - how long to wait (in milliseconds) before abandoning peer connection (defaults to 6000 milliseconds / 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).

Contributing

Contributions are very welcome!

Acknowledgments

Thank you to the following projects and individuals:

• simple-peer (Licensed under MIT)

Licence

MIT Licence.