client.js

   1 const body = document.createElement('body')
   2 const root = document.createElement('div')
   3 document.title = "Strapp.io Client"
   4 body.appendChild(root)
   5 document.body = body
   6 const conf = {"iceServers": [{ "url": "stun:stun.1.google.com:19302" }] }
   7 /* Poll the server. Send get request, wait for timeout, send another request.
   8    Do this until...? Can be used for either reconnecting or waiting for answer*/
   9 function pollServerTimeout(url, data, resolve, reject) {
  10   console.log(`Polling server ${url} with ${data}`)
  11   const request = new XMLHttpRequest()
  12   request.open('GET', url, true)
  13   request.setRequestHeader('Content-Type', 'application/json' )
  14   request.setRequestHeader('X-Strapp-Type', JSON.stringify(data))
  15   request.onreadystatechange = () => {
  16     if (request.status === 200) {
  17       if(request.readyState === 4) {
  18         console.log('Client: Recieved answer from Host')
  19         console.log(request)
  20         resolve(request.response)
  21       }
  22     }
  23     else if (request.status === 504) {
  24       console.log('timed out, resending')
  25       pollServerTimeout(url, data, resolve, reject)
  26     }
  27     else {
  28       reject('server unhandled response of status ' + request.status)
  29     }
  30   }
  31   request.send()
  32 }
  33
  34 /* TODO: All this does is wrap a function in a promise */
  35 function pollServer(url, clientPubKey, func) {
  36   return new Promise((resolve, reject) => {
  37     func(url, clientPubKey, resolve, reject )
  38   })
  39 }
  40
  41 /* TODO: duplicate in both client.js and host.js */
  42 function getPublicKey() {
  43   return new Promise( (resolve, reject) => {
  44     /* Check local storage for public key */
  45     if (!window.localStorage.getItem('public-key')) {
  46       console.log('public key is undefined')
  47       /* If doesn't exist, generate public and private key pair, store in
  48       local storage */
  49       crypto.subtle.generateKey(
  50         { name:'RSA-OAEP',
  51           modulusLength: 2048,
  52           publicExponent: new Uint8Array([0x01, 0x00, 0x01]),
  53           hash: {name: "SHA-256"}
  54         },
  55         true,
  56         ['encrypt', 'decrypt']
  57         ).then((keyPair) => {
  58           /* TODO: Do we need to store the private key as well? */
  59           crypto.subtle.exportKey('jwk', keyPair.publicKey)
  60           .then((exportedKey) => {
  61             window.localStorage.setItem('publicKey', exportedKey)
  62             console.log('public key is' + window.localStorage.getItem('publicKey'))
  63             resolve(exportedKey)
  64           })
  65
  66         })
  67     }
  68     else {
  69       resolve(window.localStorage.getItem('publicKey'))
  70     }
  71   })
  72
  73 }
  74
  75 /* Create, set, and get client Offer. Poll server for host answer.
  76    Set host answer as client remoteDescription */
  77 const cpc = new RTCPeerConnection(conf)
  78 cpc.oniceconnectionstatechange = () => {
  79   console.log('iceConnectionState = ' + cpc.iceConnectionState)
  80 }
  81 cpc.createOffer().then((offer) => {
  82   return cpc.setLocalDescription(offer)
  83 })
  84   .then(() => {
  85   console.log('sessionDescriptionInit = ' + cpc.localDescription)
  86   getPublicKey().then((cpk) => {
  87     console.log('cpk is' + cpk)
  88     let offer = {
  89       cmd: '> sdp pubKey',
  90       sdp: cpc.localDescription,
  91       pubKey: cpk
  92     }
  93     cpc.onicecandidate = (event) => {
  94       if (event.candidate) {
  95         console.log('Client: Sending ice candidate to host')
  96         pollServer(window.location, wsock.send(JSON.stringify({
  97           cmd: '> ice pubkey',
  98           ice: event.candidate,
  99           pubKey: cpk /* TODO: do we need to send this? */
 100         })), pollServerTimeout)
 101       }
 102       else {
 103         /* Set up data channel here */
 104         console.log('Client: Finished setting up ICE candidates')
 105       }
 106     }
 107     /* TODO: start polling for ice candidates, and then addIceCandidate() to cpc */
 108     //pollServer(window.location, {ice}, pollServerTimeout)
 109
 110
 111     /* Poll for answer */
 112     return pollServer(window.location, offer, pollServerTimeout)
 113   }).then((serverResponse) => {
 114     const answer = JSON.parse(serverResponse)
 115     console.log(answer)
 116     /* TODO: State machine to parse answer */
 117     console.log('Setting Remote Description')
 118     cpc.setRemoteDescription(answer.sdp)
 119   }).catch( (err) => {
 120     console.log('error in sdp handshake: ' + err)
 121   })
 122 }).catch((err) => {
 123     console.log(err)
 124 })