MultiPeerConnection

A More Efficient and User-Friendly multipeer-simple-peer-server

The main reason behind this partial rewrite is that:

1. p5LiveMedia is too high-level and contains some default p5 operations that is redundant to plain JavaScript projects.
2. multipeer-simple-peer-server uses Arrays to keep track of peers, which can be easily improved upon using the ES6 Map to achieve O(1) complexity on the client side, and is actually not necessary at all on the server side since socket.io already exposes all socket ids with io.adapter.sids and we can emit events to a specific client with io.to(SOCKET_ID).emit since socket.io automatically puts each client to a room with their own id by default.
3. multipeer-simple-peer-server does not separate the boilerplate code with user code on the client side, which was a bit inconvenient considering that there were hundreds of lines of code coupled together, and it might be hard to figure out where everything is done and what could be modified and what shouldn’t be.

I abstracted away the boilerplate code into a MultiPeerConnection class in multi-peer-connection.js so that users can easily include that file as a library and establish a multi-peer simple-peer connection with a socket.io signaling server and customize its behavior without worrying the inner works.

const multiPeerConnection = new MultiPeerConnection({
    socket: io.connect(host), // could either provide a socket instance or specify a host name
    // host: null, // default to current server if used with `server.js
    stream: videoStream, // either one `MediaStream` or a `Set` of all `MediaStream`s,
    // streams: new Set(), // default to an empty set
    onStream: receivedStreamCallback,
    onData: receivedDataCallback,
    onPeerConnect: peerConnectedCallback,
    onPeerDisconnect: peerDisconnectedCallback,
    videoBitrate: 500, // 500kbps
    audioBitrate: 100, // 100kbps
});

MultiPeerConnection has a sendData method that accepts a string and would send that through data channel to all connected peers, an addStream and a removeStream method that accept a MediaStream object and add or remove the stream for all the peers, a removeStreamsTo method that accepts the id of a connected peer and remove all streams sent to that peer, and a close method that closes the peer-to-peer connection with all peers.

MultiPeerConnection also has properties peers, socket, and streams that stores all connected peers, the current user’s socket.io socket, and all the MediaStream objects being sent to the peers, respectively.

The onStream callback takes in two parameters, the MediaStream object received from simple-peer, and the SimplePeerWrapper object from which the media stream is received.

The onData callback also takes in two parameters, the data received from simple-peer, and the SimplePeerWrapper object from which the data is received.

The onPeerConnect and onPeerDisconnect callbacks take just one parameter, the socket.io id of the connected or disconnected peer.

All options and callbacks can be ignored to create a data-channel only connection that can broadcast data but has no callback (which probably isn’t what you want, but that’s legal).