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": [{ "urls": "stun:stun.1.google.com:19302" }] }
   7
   8 /* TODO: duplicate in both client.js and host.js */
   9 function getPublicKey() {
  10   return new Promise( (resolve, reject) => {
  11     /* Check local storage for public key */
  12     if (!window.localStorage.getItem('public-key')) {
  13       console.log('public key is undefined')
  14       /* If doesn't exist, generate public and private key pair, store in
  15       local storage */
  16       crypto.subtle.generateKey(
  17         { name:'RSA-OAEP',
  18           modulusLength: 2048,
  19           publicExponent: new Uint8Array([0x01, 0x00, 0x01]),
  20           hash: {name: "SHA-256"}
  21         },
  22         true,
  23         ['encrypt', 'decrypt']
  24         ).then((keyPair) => {
  25           /* TODO: Do we need to store the private key as well? */
  26           crypto.subtle.exportKey('jwk', keyPair.publicKey)
  27           .then((exportedKey) => {
  28             window.localStorage.setItem('publicKey', exportedKey)
  29             console.log('public key is' + window.localStorage.getItem('publicKey'))
  30             resolve(exportedKey)
  31           })
  32
  33         })
  34     }
  35     else {
  36       resolve(window.localStorage.getItem('publicKey'))
  37     }
  38   })
  39
  40 }
  41
  42 function postServer(url, data) {
  43   const request = new XMLHttpRequest()
  44   request.open('POST', url, true)
  45   request.setRequestHeader('Content-Type', 'application/json' )
  46   request.setRequestHeader('X-Strapp-Type', 'ice-candidate-submission')
  47   request.send(data)
  48 }
  49
  50 /* TODO: All this does is wrap a function in a promise */
  51 function pollServer(url, clientPubKey, func) {
  52   return new Promise((resolve, reject) => {
  53     func(url, clientPubKey, resolve, reject )
  54   })
  55 }
  56
  57 /* Poll the server. Send get request, wait for timeout, send another request.
  58    Do this until...? Can be used for either reconnecting or waiting for answer*/
  59 function pollServerForAnswer(url, data, resolve, reject) {
  60   const request = new XMLHttpRequest()
  61   request.open('GET', url, true)
  62   /* But there is no JSON? */
  63   request.setRequestHeader('Content-Type', 'application/json' )
  64   request.setRequestHeader('X-Strapp-Type', 'client-sdp-offer')
  65   request.setRequestHeader('X-Client-Offer', JSON.stringify(data))
  66   request.onreadystatechange = () => {
  67     if (request.status === 200) {
  68       if(request.readyState === 4) {
  69         console.log('Client: Recieved response from Host')
  70         console.log(request)
  71         resolve(request.response)
  72       }
  73     }
  74     else if (request.status === 504) {
  75       console.log('timed out, resending')
  76       pollServerTimeout(url, data, resolve, reject)
  77     }
  78     else {
  79       reject('server unhandled response of status ' + request.status)
  80     }
  81   }
  82   request.send()
  83 }
  84
  85 /* Poll server for ice candidates until ice is complete */
  86 function pollServerForICECandidate(cpc) {
  87   window.setInterval(() => {
  88     if (cpc.iceGatheringState !== 'complete') {
  89       return new Promise((resolve, reject) => {
  90          console.log('Client: Requesting ICE Candidates from server')
  91          const request = new XMLHttpRequest()
  92          request.open('GET', window.location, true)
  93          request.setRequestHeader('Content-Type', 'application/json' )
  94          request.setRequestHeader('X-Strapp-Type', 'ice-candidate-request')
  95          request.onreadystatechange = () => {
  96            if (request.status === 200) {
  97              if(request.readyState === 4) {
  98                console.log('Client: Recieved ICE Candidate from Host')
  99                resolve(request.response)
 100              }
 101            }
 102            else if (request.status === 204) {
 103              console.log('Ice Candidate unavailable, trying again in one second')
 104            }
 105            else {
 106              reject('server unhandled response of status ' + request.status)
 107            }
 108          }
 109          request.send(cpc.pubKey)
 110       }).then((response) => {
 111         cpc.addIceCandidate(response.candidate)
 112       }).catch((err) => {
 113         console.log('pollServerForICECandidate: ' + err)
 114       })
 115     }
 116     else {
 117       clearTimeout()
 118     }
 119   }, 2000)
 120 }
 121
 122 /* Create, set, and get client Offer. Poll server for host answer.
 123    Set host answer as client remoteDescription */
 124 getPublicKey().then((cpk) => {
 125   const cpc = new RTCPeerConnection(conf)
 126   /* Start data channel */
 127   sendChannel = cpc.createDataChannel("sendChannel");
 128   sendChannel.onopen = () => {
 129     console.log('client data channel on line')
 130     sendChannel.onmessage = (message) => {
 131       console.log(message.data)
 132     }
 133     sendChannel.send('Hi from the Client')
 134   };
 135   /* Start polling for ice candidate */
 136
 137
 138   console.log(cpc.iceConnectionState)
 139   cpc.oniceconnectionstatechange = () => {
 140     console.log('iceConnectionState = ' + cpc.iceConnectionState)
 141   }
 142
 143
 144
 145   cpc.onnegotiationneeded = () => {
 146     cpc.createOffer().then((offer) => {
 147       return cpc.setLocalDescription(offer)
 148     })
 149     .then(() => {
 150       console.log('Client: Sending offer to host')
 151       let offer = {
 152         cmd: '> sdp pubKey',
 153         sdp: cpc.localDescription,
 154         pubKey: cpk.n
 155       }
 156       return pollServer(window.location, offer, pollServerForAnswer)
 157     }).then((serverResponse) => {
 158       const answer = JSON.parse(serverResponse)
 159       console.log('Client: received host answer')
 160       cpc.setRemoteDescription(answer.sdp).then(() => {
 161         console.log('Client: Polling for ICE candidates')
 162         pollServerForICECandidate(cpc)
 163       })
 164       cpc.onicecandidate = (event) => {
 165         if (event.candidate) {
 166           console.log('Client: Sending ice candidate to host')
 167           postServer(window.location, JSON.stringify({
 168             cmd: '> ice pubkey',
 169             ice: event.candidate,
 170             pubKey: cpk.n
 171           }))
 172         }
 173         else {
 174           console.log('Client: No more Ice Candidates to send')
 175         }
 176       }
 177     }).catch( (err) => {
 178       console.log('error in sdp handshake: ' + err)
 179     })
 180   }
 181 })