This module provides an easy and reliable way to setup a WebRTC connection between peers and communicate using events (the socket.io-protocol).

Socket.IO is used to transport signalling data and as a fallback for clients where WebRTC PeerConnection is not supported.

How to use

Create a socket connection, pass it to P2P. On the Client:

var P2P = require('socket.io-p2p');
var io = require('socket.io-client');
var socket = io();

var p2p = new P2P(socket);

p2p.on('ready', function(){
  p2p.usePeerConnection = true;
  p2p.emit('peer-obj', { peerId: peerId });
})

// this event will be triggered over the socket transport 
// until `usePeerConnection` is set to `true`
p2p.on('peer-msg', function(data){
  console.log(data);
});

If you're not using browserify, then use the included standalone file socketiop2p.min.js. This exports a P2P constructor on window.

On the server, use the socket.io-p2p-server to take care of signalling. All clients who support WebRTC data connections will exchange signalling data via the default / namespace.

var server = require('http').createServer();
var io = require('socket.io')(server);
var p2p = require('socket.io-p2p-server').Server;
io.use(p2p);
server.listen(3030);

WebRTC Peer connections can also be established by exchanging signalling data within a socket.io room. Do this by calling the p2p server within the connection callback:

var server = require('http').createServer();
var io = require('socket.io')(server);
var p2p = require('socket.io-p2p-server').Server;
server.listen(3030);

io.on('connection', function(socket){
  clients[socket.id] = socket;
  socket.join(roomName);
  p2p(socket, null, room);
});

See chat app for full example.

API

p2psocket = new P2P(socket, opts, cb)

Create a new socket.io-p2p connection.

The opts object can include options for setup of the overall socket.io-p2p connection as well as options for the individual peers - specified using peerOpts.

• numClients - max number of peers each client can connect to; 5 by default.
• autoUpgrade - upgrade to a p2p connection (from s.io one) when peers are ready; true by default
• peerOpts - object of options to be passed to underlying peers. See here for currently supported options.

cb is an optional callback. Called when connection is upgraded to a WebRTC connection.

p2psocket.on('upgrade', function (data) {})

Triggered when P2P connection is converted to a WebRTC one.

p2psocket.on('peer-error', function (data) {})

Triggered when a PeerConnection object errors during signalling.

Roadmap of development

• Support for packets containing multiple binary blobs - packets can only contain one blob in this version
• Allow a peer to act as a relay between peers that don't support PeerConnection and those that do.

PRs and issue reports are most welcome.