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
   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 with offer ' + data)
  11   const request = XMLHttpRequest()
  12   request.open('GET', url)
  13   request.setRequestHeader('Content-Type', 'application/json' )
  14   request.onreadystatechange = () => {
  15     if (request.status === 200) {
  16       console.log('recieved answer from host ' + request.response)
  17       resolve(request.response)
  18     }
  19     else if (request.status === 504) {
  20       pollServerTimeout(url, data, resolve, reject)
  21     }
  22     else {
  23       reject('server errored out with ' + request.status)
  24     }
  25   }
  26   request.send(data)
  27 }
  28
  29 /* TODO: Possible to pass resolve/reject to functions? */
  30 function pollServer(url, clientPubKey, func) {
  31   return new Promise((resolve, reject) => {
  32     func(url, clientPubKey, resolve, reject )
  33   })
  34 }
  35 /* If https connection, should be already defined. If not https,*/
  36 function getPublicKey() {
  37   /* Check local storage for public key */
  38   if (window.localStorage.getItem('public-key') === undefined) {
  39     /* If doesn't exist, generate public and private key pair, store in
  40     local storage */
  41     crypto.subtle.generateKey({name:'RSA-OAEP', length: 192}, true, ['encrypt', 'decrypt'])
  42       .then((keyPair) => {
  43         /* TODO: Do we need to store the private key as well? */
  44         window.localStorage.setItem('public-key', keyPair.type.public.toString())
  45       })
  46   }
  47     console.log(window.localStorage.getItem('public-key'))
  48     return window.localStorage.getItem('public-key')
  49 }
  50
  51 /* Create, set, and get client Offer. Poll server for host answer.
  52    Set host answer as client remoteDescription */
  53 const cpc = new RTCPeerConnection()
  54 cpc.createOffer().then((offer) => {
  55   console.log('creating offer which is ' + offer)
  56   return cpc.setLocalDescription(offer)
  57 }).then(() => {
  58   console.log('sessionDescriptionInit = ' + cpc.localDescription)
  59   const cpk = getPublicKey()
  60   let offer = {
  61     cmd: '> sdp pubKey'
  62     sdp: cpc.localDescription,
  63     pubKey: cpk
  64   }
  65   /* Poll for answer */
  66   return pollServer(window.location, offer, pollServerTimeout)
  67 }).then((answer) => {
  68   /* TODO: Extract sdp from answer ?*/
  69   console.log(answer)
  70   /* State machine to parse answer */
  71   cpc.setRemoteDescription(answer.sdp)
  72 })