host.js

   1 document.title = "Strapp.io Host"
   2 const conf = {"iceServers": [{ "url": "stun:stun.1.google.com:19302" }] }
   3 const clients = new Map([])
   4 const hpk = getPublicKey()
   5
   6 /* TODO: duplicate in both client.js and host.jhs */
   7 function getPublicKey() {
   8   return new Promise( (resolve, reject) => {
   9     /* Check local storage for public key */
  10     if (!window.localStorage.getItem('public-key')) {
  11       console.log('public key is undefined')
  12       /* If doesn't exist, generate public and private key pair, store in
  13       local storage */
  14       crypto.subtle.generateKey(
  15         { name:'RSA-OAEP',
  16         modulusLength: 2048,
  17         publicExponent: new Uint8Array([0x01, 0x00, 0x01]),
  18         hash: {name: "SHA-256"}
  19       },
  20       true,
  21       ['encrypt', 'decrypt']
  22     ).then((keyPair) => {
  23       /* TODO: Do we need to store the private key as well? */
  24       crypto.subtle.exportKey('jwk', keyPair.publicKey)
  25       .then((exportedKey) => {
  26         window.localStorage.setItem('publicKey', exportedKey)
  27         console.log('public key is' + window.localStorage.getItem('publicKey'))
  28         resolve(exportedKey)
  29       })
  30
  31     })
  32   }
  33   else {
  34     resolve(window.localStorage.getItem('publicKey'))
  35     }
  36   })
  37 }
  38
  39
  40 function handleNewClientConnection(offer) {
  41   /* New Client Connection*/
  42   hpc = new RTCPeerConnection(conf)
  43   hpc.setRemoteDescription(offer.sdp)
  44   .then(() => {
  45     hpc.createAnswer().then((answer) => {
  46       return hpc.setLocalDescription(answer)
  47     })
  48     .then(() => {
  49       hpk.then(() => {
  50         hpc.onicecandidate = (event) => {
  51           if (event.candidate) {
  52             console.log('Host: Sending ice candidate to client')
  53             wsock.send(JSON.stringify({
  54               cmd: '< ice pubKey',
  55               ice: event.candidate,
  56               pubKey: hpk /* TODO: do we need to send this? */
  57             }))
  58           }
  59           else {
  60             console.log('Host: Finished setting up ICE candidates')
  61           }
  62         }
  63         console.log('Host: Sending answer to Host')
  64         wsock.send(JSON.stringify({
  65           cmd: '< sdp pubKey',
  66           sdp: hpc.localDescription,
  67           pubKey: hpk
  68         }))
  69         clients.set(offer.pubKey, {
  70           hostsdp: hpc.localDescription,
  71           clientsdp: hpc.remoteDescription
  72         })
  73
  74       })
  75     }).catch((err) => {
  76       console.log(`error in host answer ${err}`)
  77     })
  78   })
  79 }
  80
  81 function handleNewIceCandidate(msg) {
  82   const hpc = clients.get(msg.pubKey)
  83   let candidate = new RTCIceCandidate(msg.ice)
  84   hpc.addIceCandidate(candidate)
  85 }
  86
  87 if ("WebSocket" in window) {
  88   document.addEventListener('DOMContentLoaded', (event) => {
  89     wsock = new WebSocket(`${_strapp_protocol}://${window.location.hostname}:${_strapp_port}`)
  90     wsock.onopen = () => {
  91       console.log(`Strapped to ${_strapp_protocol}://${window.location.hostname}:${_strapp_port}`)
  92     }
  93
  94     wsock.onmessage = (serverMsg) => {
  95       /* msg is either offer or ice candidate */
  96       console.log(serverMsg.data)
  97       let msg = JSON.parse(serverMsg.data)
  98
  99       const clientID = msg.pubKey
 100       const msgType = msg.hasOwnProperty('sdp') ? 'o' : 'i'
 101       if (clients.has(clientID)) {
 102         switch(msgType) {
 103           case 'o':
 104           console.log('client exist && sending an offer == error')
 105           break
 106           case 'i':
 107           handleNewIceCandidate(msg)
 108           break
 109         }
 110       }
 111       else {
 112         switch(msgType) {
 113           case 'o':
 114           handleNewClientConnection(msg)
 115           break
 116           case 'i':
 117           console.log('client !exist && ice candidate === error')
 118           break
 119         }
 120       }
 121     }
 122   })
 123 }
 124 else {
 125   document.addEventListener('DOMContentLoaded', () => {
 126     document.body.innerHTML = 'Websockets not supported in your browser'
 127   })
 128 }