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({
  17   peerId,
  18   shouldCreateOffer,
  19   mediaStream,
  20   onOffer,
  21   socket,
  22 }) {
  23   const peerConnection = new RTCPeerConnection(
  24     { iceServers: internals.kIceServers },
  25     { optional: [{ DtlsSrtpKeyAgreement: true }] },
  26   );
  27
  28   internals.peers[peerId] = peerConnection;
  29   mediaStream.getTracks().forEach((track) => {
  30     peerConnection.addTrack(track, mediaStream);
  31   });
  32
  33   peerConnection.onicecandidate = (event) => {
  34     if (event.candidate) {
  35       socket.emit("relayICECandidate", {
  36         peerId: peerId,
  37         candidate: event.candidate,
  38       });
  39     }
  40   };
  41
  42   const remoteStream = new MediaStream();
  43   peerConnection.ontrack = (event) => {
  44     remoteStream.addTrack(event.track);
  45     const remoteAudioElement = new Audio();
  46     remoteAudioElement.srcObject = remoteStream;
  47     remoteAudioElement.play();
  48   };
  49
  50   peerConnection.onnegotiationneeded = async () => {
  51     if (shouldCreateOffer) {
  52       console.debug("Creating RTC offer to ", peerId);
  53       const offer = await peerConnection.createOffer();
  54       await peerConnection.setLocalDescription(offer);
  55
  56       onOffer({ peerId, offer });
  57     }
  58   };
  59
  60   console.info(`There are now ${countPeers()} participants`);
  61 }
  62
  63 export function removePeer({ peerId }) {
  64   delete internals.peers[peerId];
  65   console.info(`There are now ${countPeers()} participants`);
  66 }
  67
  68 export async function answerPeerOffer({ peerId, offer }) {
  69   console.info(`Answering peer ${peerId}`);
  70   const peerConnection = internals.peers[peerId];
  71
  72   const remoteDescription = new RTCSessionDescription(offer);
  73   await peerConnection.setRemoteDescription(remoteDescription);
  74
  75   const answer = await peerConnection.createAnswer();
  76   await peerConnection.setLocalDescription(answer);
  77
  78   return { peerId, answer };
  79 }
  80
  81 export async function processPeerAnswer({ peerId, answer }) {
  82   console.info(`Processing answer for peer ${peerId}`);
  83   const peerConnection = internals.peers[peerId];
  84   const remoteDescription = new RTCSessionDescription(answer);
  85   await peerConnection.setRemoteDescription(remoteDescription);
  86 }
  87
  88 export async function addIceCandidate({ peerId, candidate }) {
  89   console.info(`Adding ICE candidate for peer ${peerId}`);
  90   const peerConnection = internals.peers[peerId];
  91   console.info(peerConnection.signalingState);
  92   const iceCandidate = new RTCIceCandidate(candidate);
  93   await peerConnection.addIceCandidate(iceCandidate);
  94 }
  95
  96 export function countPeers() {
  97   return Object.keys(internals.peers).length;
  98 }
  99
 100 export function resetPeers() {
 101   internals.peers = {};
 102   document
 103     .querySelectorAll(".junction-call-audio")
 104     .forEach((audioElement) => audioElement.remove());
 105 }