git.r.bdr.sh - rbdr/junction/blob - extension/peers.js

   1 const internals = {
   2   peers: {},
   3
   4   createAudioElement(source) {
   5     const audioElement = document.createElement("audio");
   6     audioElement.setAttribute("class", "junction-call-audio");
   7     audioElement.autoplay = "autoplay";
   8     audioElement.srcObject = source;
   9
  10     document.querySelector("body").appendChild(audioElement);
  11
  12     return audioElement;
  13   },
  14 };
  15
  16 export function addPeer({ peerId, mediaStream, onOffer, socket }) {
  17   const peerConnection = new RTCPeerConnection(
  18     { iceServers: internals.kIceServers },
  19     { optional: [{ DtlsSrtpKeyAgreement: true }] },
  20   );
  21
  22   internals.peers[peerId] = peerConnection;
  23   mediaStream.getTracks().forEach((track) => {
  24     peerConnection.addTrack(track, mediaStream);
  25   });
  26
  27   peerConnection.onicecandidate = (event) => {
  28     if (event.candidate) {
  29       socket.emit("relayICECandidate", {
  30         peerId: peerId,
  31         candidate: event.candidate,
  32       });
  33     }
  34   };
  35
  36   const remoteStream = new MediaStream();
  37   peerConnection.ontrack = (event) => {
  38     remoteStream.addTrack(event.track);
  39     const remoteAudioElement = new Audio();
  40     remoteAudioElement.srcObject = remoteStream;
  41     remoteAudioElement.play();
  42   };
  43
  44   peerConnection.onnegotiationneeded = async () => {
  45     console.debug("Creating RTC offer to ", peerId);
  46     const offer = await peerConnection.createOffer();
  47     await peerConnection.setLocalDescription(offer);
  48
  49     onOffer({ peerId, offer });
  50   };
  51
  52   console.info(`There are now ${countPeers()} participants`);
  53 }
  54
  55 export function removePeer({ peerId }) {
  56   delete internals.peers[peerId];
  57   console.info(`There are now ${countPeers()} participants`);
  58 }
  59
  60 export async function answerPeerOffer({ peerId, offer }) {
  61   const peerConnection = internals.peers[peerId];
  62
  63   const remoteDescription = new RTCSessionDescription(offer);
  64   await peerConnection.setRemoteDescription(remoteDescription);
  65
  66   const answer = await peerConnection.createAnswer();
  67   await peerConnection.setLocalDescription(answer);
  68
  69   return { peerId, answer };
  70 }
  71
  72 export async function processPeerAnswer({ peerId, answer }) {
  73   const peerConnection = internals.peers[peerId];
  74   const remoteDescription = new RTCSessionDescription(answer);
  75   await peerConnection.setRemoteDescription(remoteDescription);
  76 }
  77
  78 export async function addIceCandidate({ peerId, candidate }) {
  79   const peerConnection = internals.peers[peerId];
  80   const iceCandidate = new RTCIceCandidate(candidate);
  81   await peerConnection.addIceCandidate(iceCandidate);
  82 }
  83
  84 export function countPeers() {
  85   return Object.keys(internals.peers).length;
  86 }
  87
  88 export function resetPeers() {
  89   internals.peers = {};
  90   document
  91     .querySelectorAll(".junction-call-audio")
  92     .forEach((audioElement) => audioElement.remove());
  93 }