simple-peer

Simple WebRTC video/voice and data channels.

features

• super simple API for working with WebRTC
• supports video/voice streams
• supports data channel
  • text and binary data
  • optionally, treat data channel as a node.js duplex stream
• supports advanced options like:
  • enable/disable trickle ICE candidates
  • manually set config and constraints options

This module works great in the browser with browserify, and it's used by WebTorrent!

install

npm install simple-peer

usage

These examples create two peers in the same page.

In a real-world application, the sender and receiver Peer instances would exist in separate browsers. A "signaling server" (usually implemented with websockets) would be used to exchange signaling data between the two browsers until a peer-to-peer connection is established.

data channels

var SimplePeer = require('simple-peer')

var peer1 = new SimplePeer({ initiator: true })
var peer2 = new SimplePeer()

peer1.on('signal', function (data) {
  // when peer1 has signaling data, give it to peer2
  peer2.signal(data)
})

peer2.on('signal', function (data) {
  // same as above, but in reverse
  peer1.signal(data)
})

peer1.on('ready', function () {
  // wait for 'ready' event before using the data channel
  peer1.send('hey peer2, how is it going?')
})

peer2.on('message', function (data) {
  // got a data channel message
  console.log('got a message from peer1: ' + data)
})

Note: If you're NOT using browserify, then use the standalone simplepeer.bundle.js file included in this repo. This exports a SimplePeer function on the window.

video/voice

Video/voice is also super simple! In this example, peer1 sends video to peer2.

var SimplePeer = require('simple-peer')

// get video/voice stream
navigator.getUserMedia({ video: true, audio: true }, gotMedia, function () {})

function gotMedia (stream) {
  var peer1 = new SimplePeer({ initiator: true, stream: stream })
  var peer2 = new SimplePeer()

  peer1.on('signal', function (data) {
    peer2.signal(data)
  })

  peer2.on('signal', function (data) {
    peer1.signal(data)
  })

  peer2.on('stream', function (stream) {
    // got remote video stream, now let's show it in a video tag
    var video = document.querySelector('video')
    video.src = window.URL.createObjectURL(stream)
    video.play()
  })
}

For two-way video, simply pass a stream option into both Peer constructors. Simple!

api

peer = new SimplePeer([opts])

Create a new WebRTC peer connection.

A "data channel" for text/binary communication is always established, because it's cheap and often useful. For video/voice communication, pass the stream option.

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

{
  initiator: false,
  stream: false,
  config: { iceServers: [ { url: 'stun:23.21.150.121' } ] },
  constraints: {},
  channelName: 'simple-peer-<random string>',
  trickle: true
}

The options do the following:

• initiator - set to true if this is the initiating peer
• stream - if video/voice is desired, pass stream returned from getUserMedia
• config - custom webrtc configuration
• constraints - custom webrtc video/voice constaints
• channelName - custom webrtc data channel name
• trickle - set to false to disable trickle ICE and get a single 'signal' event (slower)

peer.signal(data)

Call this method whenever the remote peer emits a peer.on('signal') event.

The data will be a String that encapsulates a webrtc offer, answer, or ice candidate. These messages help the peers to eventually establish a direct connection to each other. The contents of these strings are an implementation detail that can be ignored by the user of this module; simply pass the data from 'signal' events to the remote peer, call peer.signal(data), and everything will just work.

peer.send(data)

Send text/binary data to the remote peer. data can be any of several types: String, Buffer (see buffer), TypedArrayView (Uint8Array, etc.), or ArrayBuffer.

Note: this method should not be called until the peer.on('ready') event has fired.

peer.destroy([onclose])

Destroy and cleanup this peer connection.

If the optional onclose paramter is passed, then it will be registered as a listener on the 'close' event.

stream = peer.getDataStream()

Returns a duplex stream which reads/writes to the data channel.

Very handy for treating the data channel just like any other node.js stream!

events

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

Fired when the peer connection and data channel are ready to use.

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

Fired when the peer wants to send signaling data to the remote peer.

It is the responsibility of the application developer (that's you!) to get this data to the other peer. This usually entails using a websocket signaling server. Then, simply call peer.signal(data) on the remote peer.

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

Received a message from the remote peer (via the data channel).

data will be either a String or a Buffer/Uint8Array (see buffer).

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

Called when the peer connection has closed.

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

Fired when a fatal error occurs. Usually, this means bad signaling data was received from the remote peer.

err is an Error object.

real-world applications that use simple-peer

• lxjs-chat - Omegle chat clone
• instant.io - Secure, anonymous, streaming file transfer
• [ your application here - send a PR ]

license

MIT. Copyright (c) Feross Aboukhadijeh.