A WebRTC library that makes it easy to embed scalable peer to peer communication into UI components.
LioWebRTC works standalone, but it is also compatible with React, Vue, Electron, etc. It can be configured for scalability using partial mesh networks, making it possible to emit data to thousands of peers in a room, while only needing to be connected to at least one other peer in the room.
Click here to see a chatroom demo built with LioWebRTC.
Click here to see a video conferencing demo app built with LioWebRTC.
React developers may want to take a look at react-liowebrtc.
yarn add liowebrtc
// Or
npm i liowebrtcimport LioWebRTC from 'liowebrtc';By default, this enables video, audio, and data channels.
const webrtc = new LioWebRTC({
localVideoEl: localVideoIdOrRef, // The local video element
autoRequestMedia: true, // Immediately request camera and mic access upon initialization
debug: true, // Displays events emitted by liowebrtc in the console
url: 'https://your-signaling-server.com:443/' // The url for your signaling server. If no url is passed, liowebrtc uses the default demo signaling server. (The default server is for demo purposes only, and is not reliable. Plus, I'm the only one paying for it 🙁. Please use your own in production!)
});Disable video/audio streaming, and only allow data channels.
const webrtc = new LioWebRTC({
dataOnly: true
});Great for voice calls.
const webrtc = new LioWebRTC({
autoRequestMedia: true,
media: {
video: false,
audio: true
}
});Peers only form direct connections with a maximum of maxPeers and a minimum of minPeers. shout()ing still works because peers wil re-propagate messages to other peers. Note: partial mesh networks only work if you're only using dataOnly.
const webrtc = new LioWebRTC({
dataOnly: true,
network: {
maxPeers: 8,
minPeers: 4
}
})webrtc.on('ready', () => {
// Joins a room if it exists, creates it if it doesn't
webrtc.joinRoom('your room name');
});Sometimes a peer wants to let every other peer in the room to know about something. This can be accomplished with
shout(messageType, payload)
webrtc.shout('event-label', { success: true, payload: '137' });Now for the recipients, handle the peer event with a listener:
webrtc.on('receivedPeerData', (type, data, peer) => {
if (type === 'event-label' && data.success) {
console.log(`Peer ${peer.id} emitted ${data.payload}`);
}
});Sometimes a peer only wants to send data directly to another peer. This can be accomplished with
whisper(peer, messageType, payload)
webrtc.whisper(peer, 'directMessage', { msg: 'Hello world!' });Receiving the message is the same as handling a peer event:
webrtc.on('receivedPeerData', (type, data, peer) => {
if (type === 'directMessage') console.log(`Peer ${peer.id} says: ${data.msg}`);
});componentDidUpdate(prevProps, prevState) {
if (this.state.position !== prevState.position) {
this.webrtc.shout('stateUpdate', this.state);
}
}
});All communications via shout/whisper are sent over the default data channel and emitted by the LioWebRTC instance as events. You can create your own custom listeners suited for whatever purpose you'd like.
webrtc.on('peerStreamAdded', (stream, peer) => {
webrtc.attachStream(stream, yourVideoElementOrRef);
});import React, { Component } from 'react';
import LioWebRTC from 'liowebrtc';
class Party extends Component {
constructor(props) {
super(props);
this.state = {
nick: this.props.nick,
roomID: `party-${this.props.roomName}`,
muted: false,
camPaused: false,
peers: []
};
this.remoteVideos = {};
}
componentDidMount() {
this.webrtc = new LioWebRTC({
// The url for your signaling server. Use your own in production!
url: 'https://sm1.lio.app:443/',
// The local video ref set within your render function
localVideoEl: this.localVid,
// Immediately request camera access
autoRequestMedia: true,
// Optional: nickname
nick: this.state.nick,
debug: true
});
this.webrtc.on('peerStreamAdded', this.addVideo);
this.webrtc.on('removedPeer', this.removeVideo);
this.webrtc.on('ready', this.readyToJoin);
this.webrtc.on('iceFailed', this.handleConnectionError);
this.webrtc.on('connectivityError', this.handleConnectionError);
}
addVideo = (stream, peer) => {
this.setState({ peers: [...this.state.peers, peer] }, () => {
this.webrtc.attachStream(stream, this.remoteVideos[peer.id]);
});
}
removeVideo = (peer) => {
this.setState({
peers: this.state.peers.filter(p => !p.closed)
});
}
handleConnectionError = (peer) => {
const pc = peer.pc;
console.log('had local relay candidate', pc.hadLocalRelayCandidate);
console.log('had remote relay candidate', pc.hadRemoteRelayCandidate);
}
readyToJoin = () => {
// Starts the process of joining a room.
this.webrtc.joinRoom(this.state.roomID, (err, desc) => {
});
}
// Show fellow peers in the room
generateRemotes = () => this.state.peers.map((p) => (
<div key={p.id}>
<div id={/* The video container needs a special id */ `${this.webrtc.getContainerId(p)}`}>
<video
// Important: The video element needs both an id and ref
id={this.webrtc.getDomId(p)}
ref={(v) => this.remoteVideos[p.id] = v}
/>
</div>
<p>{p.nick}</p>
</div>
));
disconnect = () => {
this.webrtc.quit();
}
componentWillUnmount() {
this.disconnect();
}
render() {
return (
<div>
<div>
<video
// Important: The local video element needs to have a ref
ref={(vid) => { this.localVid = vid; }}
/>
<p>{this.state.nick}</p>
</div>
{this.generateRemotes()}
</div>
);
}
}
export default Party;new LioWebRTC(options)
object optionsstring url- url for your socket.io signaling serverbool debug- optional logs all webrtc eventsstring nick- optional sets your nickname. Peers' nicknames can be accessed withpeer.nick[string|DomElement|Ref] localVideoEl- Can be a ref, DOM element, or ID of the local videobool autoRequestMedia- optional(=false) automatically request user media. Usetrueto request automatically, orfalseto request media later withstartLocalVideobool dataOnlyoptional(=false) option to ensure that video and audio stream channels are turned offbool autoRemoveVideos- optional(=true) option to automatically remove video elements when streams are stopped.bool adjustPeerVolume- optional(=true) option to reduce peer volume when the local participant is speakingnumber peerVolumeWhenSpeaking- optional(=.0.25) value used in conjunction withadjustPeerVolume. Uses values between 0 and 1object media- media options to be passed togetUserMedia. Defaults to{ video: true, audio: true }. Valid configurations described on MDN with official spec at w3c.object receiveMedia- optional RTCPeerConnection options. Defaults to{ offerToReceiveAudio: 1, offerToReceiveVideo: 1 }.object localVideo- optional options for attaching the local video stream to the page. Defaults to
{ autoplay: true, // automatically play the video stream on the page mirror: true, // flip the local video to mirror mode (for UX) muted: true // mute local video stream to prevent echo }
object constraints- optional options for setting minimum and maximum peers to connect to. Defaults to
{ minPeers: 2, // connect to at least 2 peers maxPeers: 0 // when 0, maxPeers is infinite }
bool selfOptimize- optional(=true) whether or not peers in a partial mesh network should self-optimize their connections. LioWebRTC uses a more object-oriented version of an adjacency list to represent the p2p graph, with the weights of the edges representing roundtrip latency between two nodes. WithselfOptimizeset to true, peers automatically disconnect from neighbors with latencies >=1 std. deviation from the mean, and reconnect to a new random peer.
connection - the socket signaling connection
webrtc - the underlying WebRTC session manager
To set up event listeners, use the LioWebRTC instance created with the constructor. Example:
// Emitted when a peer's media stream becomes available
this.webrtc.on('peerStreamAdded', (stream, peer) => {
// Attach the MediaStream to a video element
// this.webrtc.attachStream(stream, this.remoteVideos[peer.id]);
});
// Emitted when we receive data from a peer via the data channel
this.webrtc.on('receivedPeerData', (type, payload, peer) => {
// Find something to do with the data
});'channelOpen', RTCDataChannel, peer - emitted when a new channel is established with a peer.
'connectionReady', sessionId - emitted when the signaling connection emits the
connect event, with the unique id for the session.
'createdPeer', peer - this will be emitted when:
- joining a room with existing peers, once for each peer
- a new peer joins your room
'joinedRoom', roomName - emitted after successfully joining a room.
'leftRoom', roomName - emitted after successfully leaving the current room,
ending all peers, and stopping local stream
'mute', data - emitted when a peer mutes their video or audioOn
dataan object that contains anidproperty that returns the id of the peer, and anameproperty that indicates which stream was muted,videooraudio
'removedPeer', peer - emitted when a peer loses connection or exits the room
peer- the peer associated with the stream that was removed
'ready', sessionId - emitted when liowebrtc is ready to join a room
sessionId- the socket.io connection session ID
'receivedPeerData', type, payload, peer - emitted when data is received from a peer that sent the data with shout or whisper
typea label, usually a string, that describes the payloadpayloadany kind of data sent by the peer, usually an objectpeerthe object representing the peer and its peer connection
'receivedSignalData', type, payload, peer - emitted when data is received from a peer that sent the data via the socket.io signaling server with broadcast or transmit
typea label, usually a string, that describes the payloadpayloadany kind of data sent by the peer, usually an objectpeerthe object representing the peer and its peer connection
'stunservers', [...args] - emitted when the signaling server emits a list of stun servers.
'turnservers', [...args] - emitted when the signaling server emits a list of turn servers.
'unmute', data - emitted when a peer mutes their video or audioOn
dataan object that contains anidproperty for the id of the peer that sent the event, and anameproperty that indicates which stream was muted,videooraudio
'peerStreamAdded', stream, peer - emitted when a peer's MediaStream becomes available
stream- the MediaStream associated with the peerpeer- the peer associated with the stream that was added
'peerStreamRemoved', peer - emitted when a peer stream is removed
peer- the peer associated with the stream that was removed
attachStream(stream, el, opts) - attaches a media stream to a video or audio element
MediaStream stream- an object representing a local or peer media streamHTMLElement el- the element (or ref if you're using React) to attach the media stream to, usually a video or audio elementobject opts- optional optional configuration for attachStreambool autoplay- autoplay the video once attached. Defaults totruebool muted- mute the video once attached. Defaults tofalsebool mirror- mirror the video once attached. Defaults totruebool audio- attach to<audio>element instead of<video>element. Defaults tofalse
broadcast(messageType, payload) - broadcasts a message to all peers in the
room via the signaling server (similar to shout, but not p2p). Listen for peers' broadcasts on the receivedSignalData event.
string messageTypean arbitrary label, usually a string, that describes the payloadobject payload- an arbitrary value or object to send to peers
createRoom(name, callback) - emits the create event and optionally invokes callback on response
disconnect() - calls disconnect on the signaling connection and deletes it. Peers will still be available
emit(eventLabel, ...args) - emit arbitrary event (Emits locally. To emit stuff other peers, use shout)
getClients((err, clients)) - asks the socket.io signaling server for a list of peers currently in the room.
object clients- An object whose keys are the client IDs and values are client types.
getContainerId(peer) - get the DOM id associated with a peer's media element. In JSX, you will need to set the id of the container element to this value
Peer peer- the object representing the peer and its peer connection
getMyId() - get your own peer ID
getDomId(peer) - get the DOM id associated with a peer's media stream. In JSX, you will need to set the id of the peer's media element to this value.
Peer peer- the object representing the peer and its peer connection
getPeerById(id) - returns a peer with a given id
string id- the id of the peer
getPeerByNick(nick) - returns a peer with a given nick
string nick- the peer's nickname
getPeers(sessionId) - returns all peers by sessionId
string sessionId- the sid of the current room. Will return all peers if no sessionId is provided.
joinRoom(name, callback) - joins the room name. Callback is
invoked with callback(err, roomDescription) where roomDescription is yielded
by the connection on the join event. See SignalBuddy for more info.
leaveRoom() - leaves the currently joined room and stops local streams
mute() - mutes the local audio stream to your peers (stops sending audio in the WebRTC audio channel)
on(ev, fn) - creates an event listener for event ev handled by fn
pause() - pauses both video and audio streams to your peers
pauseVideo() - pauses the video stream to your peers (stops sending video in the WebRTC video channel)
quit() - stops the local video, leaves the currently joined room, and disconnects from the signaling server
resume() - resumes sending video and audio to your peers
resumeVideo() - resumes the video stream to your peers (resumes sending video in the WebRTC video channel)
sendDirectlyToAll(messageType, payload, channel) - sends a message
to all peers in the room via a data channel (same as shout, except you can specify your own data channel. Use this if you need to set up a new data channel, e.g. a dedicated file-sharing channel, etc.)
string channel- (optional) the name of the data channel. If it doesn't exist, it will be created.
setVolumeForAll(volume) - set the volume level for all peers
shout(messageType, payload) - sends a message
to all peers in the room via the default p2p data channel. Listen for peers' shouts on the receivedPeerData event.
string messageType- an arbitrary label, usually a string, that describes the payloadobject payload- an arbitrary value or object to send to peers
startLocalVideo() - starts the local video or audio streams with the media options provided
in the config. Use this if autoRequestMedia is set to false
stopLocalVideo() - stops all local media streams
transmit(peer, messageType, payload) - sends a message to a single peer in the
room via the signaling server (similar to whisper, but not p2p). Listen for peers' transmissions on the receivedSignalData event.
Peer peer- the object representing the peer and its peer connectionstring messageType- an arbitrary label, usually a string, that describes the payloadobject payload- any kind of data sent by the peer, usually an object
unmute() - unmutes the audio stream to your peers (resumes sending audio in the WebRTC audio channel)
float volume- the volume level, between 0 and 1
whisper(peer, messageType, payload) - sends a message to a single peer in the room via the default p2p data channel. Listen for peers' whispers on the receivedPeerData event.
Peer peer- the object representing the peer and its peer connectionstring messageType- an arbitrary label, usually a string, that describes the payloadobject payload- any kind of data sent by the peer, usually an object
WebRTC needs to be facilitated with signaling; a service that acts as a matchmaker for peers before they establish direct video/audio/data channels. Signaling can be done in any way, e.g. via good old fashioned carrier pigeons. Signaling services only need to fulfill the absolute minimal role of matchmaking peers.
SignalBuddy is a scalable socket.io signaling server, and is very easy to set up. socket.io enables real-time, bidirectional communication between a client and server via web sockets. It also allows us to easily segment peers into rooms.
For emitting data to peers, LioWebRTC provides a unified, event-based API that enables peers to seamlessly switch between shouting (p2p data channels) or broadcasting (socket.io) to all the peers in a room. It's up to you to decide which protocol to use, but socket.io should ideally only be used for transmitting things like metadata, one-off events, etc. Both protocols are real-time, bidirectional, and event-based.
LioWebRTC wraps socketio-client and returns a connection object. This the connection to the signaling server. The connection object comes with the following methods:
on(ev, fn)- a method to set a listener for eventevemit()- send/emit arbitrary events on the connectiongetSessionId()- returns the session ID of the connectiondisconnect()- disconnect from the signaling server (closes the web socket)
LioWebRTC uses SignalBuddy to facilitate signaling. LioWebRTC works out of the box with a demo SignalBuddy server that was intended for testing purposes. However, for production purposes, IT IS NOT RELIABLE. In production, you will need to set up your own SignalBuddy server (or any other socket.io solution that implements matchmaking).