client.js

   1 const body = document.createElement('body')
   2 const root = document.createElement('div')
   3 document.title = "Strapp.io Client"
   4 const conf = {"iceServers": [{ "urls": "stun:stun.1.google.com:19302" }] }
   5
   6 /* TODO: This is duplicated in both client.js and host.js */
   7 function getPublicKey() {
   8   return new Promise( (resolve, reject) => {
   9     /* Check local storage for public key */
  10     if (!window.localStorage.getItem('public-key')) {
  11       /* If doesn't exist, generate public and private key pair, store in
  12       local storage */
  13       crypto.subtle.generateKey(
  14         { name:'RSA-OAEP',
  15         modulusLength: 2048,
  16         publicExponent: new Uint8Array([0x01, 0x00, 0x01]),
  17         hash: {name: "SHA-256"}
  18       },
  19       true,
  20       ['encrypt', 'decrypt']
  21     ).then((keyPair) => {
  22       /* TODO: Do we need to store the private key as well? */
  23       crypto.subtle.exportKey('jwk', keyPair.publicKey)
  24       .then((exportedKey) => {
  25         window.localStorage.setItem('publicKey', exportedKey)
  26         console.log('public key is' + window.localStorage.getItem('publicKey'))
  27         resolve(exportedKey)
  28       })
  29
  30     })
  31   }
  32   else {
  33     resolve(window.localStorage.getItem('publicKey'))
  34   }
  35 })
  36
  37 }
  38
  39 function sendHost(url, data) {
  40   const request = new XMLHttpRequest()
  41   request.open('GET', url, true)
  42   request.setRequestHeader('Content-Type', 'application/json' )
  43   request.setRequestHeader('x-strapp-type', 'ice-candidate-submission')
  44   request.send(data)
  45 }
  46
  47 /* Poll the server. Send get request, wait for timeout, send another request.
  48 Do this until...? Can be used for either reconnecting or waiting for answer*/
  49 function requestHostAnswer(url, data) {
  50   return new Promise((resolve, reject) => {
  51     const request = new XMLHttpRequest()
  52     request.open('GET', url, true)
  53     /* But there is no JSON? */
  54     request.setRequestHeader('Content-Type', 'application/json' )
  55     request.setRequestHeader('x-strapp-type', 'client-sdp-offer')
  56     request.setRequestHeader('x-strapp-pubkey', data.pubKey)
  57     request.onreadystatechange = () => {
  58       if (request.status === 200) {
  59         if(request.readyState === 4) {
  60           console.log('Client: Recieved Answer from Host')
  61           console.log(request)
  62           resolve(request.response)
  63         }
  64       }
  65       else if (request.status === 504) {
  66         console.log('timed out, resending')
  67         resolve(requestHostAnswer(url, data))
  68       }
  69       else {
  70         reject('server unhandled response of status ' + request.status)
  71       }
  72     }
  73     request.send(data)
  74   })
  75 }
  76
  77 /* Poll server for ice candidates until ice is complete */
  78 function requestHostICE(cpc, url, pubKey) {
  79   let intervalID = window.setInterval(() => {
  80     if (cpc.iceConnectionState.localeCompare('connected') !== 0
  81     && cpc.iceConnectionState.localeCompare('completed') !== 0) {
  82       console.log('Client: Polling server begin for intervalID = ' + intervalID)
  83       console.log('Client: Requesting ICE Candidates from server')
  84       const request = new XMLHttpRequest()
  85       request.open('GET', url, true)
  86       request.setRequestHeader('Content-Type', 'application/json' )
  87       request.setRequestHeader('x-strapp-Type', 'ice-candidate-request')
  88       request.setRequestHeader('x-client-pubkey', pubKey)
  89       request.onreadystatechange = () => {
  90         if (request.status === 200) {
  91           if(request.readyState === 4) {
  92             console.log('Client: Recieved ICE response from Host')
  93             let response = JSON.parse(request.response)
  94             switch(response['iceState']) {
  95               case "a":
  96               cpc.addIceCandidate(new RTCIceCandidate(response.ice))
  97               break
  98               case "g": /* Gathering so let interval keep polling */
  99               break
 100               case "c": /* host iceState == Complete, stop bugging it */
 101               clearInterval(intervalID)
 102               clearTimeout()
 103               break
 104               default:
 105               console.log('Unhandled iceState in requestHostICE()' + response['iceState'])
 106               break
 107             }
 108           }
 109         }
 110         else {
 111           console.log('server unhandled response of status ' + request.status)
 112           clearInterval(intervalID)
 113         }
 114       }
 115       request.send()
 116     }
 117     else {
 118       clearTimeout()
 119       clearInterval(intervalID)
 120     }
 121   }, 5000)
 122 }
 123
 124 /* Create and send offer -> Send ICE Candidates -> Poll for ICE Candidates */
 125 getPublicKey().then((cpk) => {
 126   let dataChannel
 127   console.log('Client: Create and send offer')
 128   const cpc = new RTCPeerConnection(conf)
 129
 130   cpc.oniceconnectionstatechange = () => {
 131     console.log('iceConnectionState = ' + cpc.iceConnectionState)
 132   }
 133
 134   cpc.onnegotiationneeded = () => {
 135     console.log('negotiation needed!')
 136     cpc.createOffer().then((offer) => {
 137       return cpc.setLocalDescription(offer)
 138     })
 139     .then(() => {
 140       console.log('Client: Sending offer to host')
 141       let offer = {
 142         cmd: '> sdp pubKey',
 143         sdp: cpc.localDescription,
 144         pubKey: cpk.n
 145       }
 146       return requestHostAnswer(window.location, offer)
 147     })
 148     .then((serverResponse) => {
 149       const answer = JSON.parse(serverResponse)
 150       console.log('Client: Polling for ICE candidates')
 151       requestHostICE(cpc, window.location, cpk.n)
 152       cpc.setRemoteDescription(answer.sdp)
 153       cpc.onicecandidate = (event) => {
 154         if (event.candidate) {
 155           console.log('Client: Sending ice candidate to host')
 156           sendHost(window.location, JSON.stringify({
 157             cmd: '> ice pubkey',
 158             ice: event.candidate,
 159             pubKey: cpk.n
 160           }))
 161         }
 162         else {
 163           console.log('Client: No more Ice Candidates to send')
 164         }
 165       }
 166
 167
 168     }).catch( (err) => {
 169       console.log('error in sdp handshake: ' + err)
 170     })
 171   }
 172   /* Start data channel, triggers on negotiation needed */
 173   dataChannel = cpc.createDataChannel("sendChannel");
 174
 175   /* Triggered when Host adds track to peer connection */
 176   cpc.ontrack = (event) => {
 177     let remoteRTPReceivers = cpc.getReceivers()
 178     let hostScreen
 179     let video = document.querySelector('video')
 180     /* TODO: Audio, video, or other track? */
 181     console.log(remoteRTPReceivers)
 182     console.log(video)
 183     hostScreen = new MediaStream([remoteRTPReceivers[0].track])
 184     if(!video.srcObject) {
 185       video.srcObject = hostScreen
 186     }
 187     console.log(hostScreen.getVideoTracks())
 188     console.log(video.srcObject)
 189     video.onloadedmetadata = () => {
 190       video.play()
 191     }
 192   }
 193
 194   dataChannel.onmessage = (msg) => {
 195     /* Get mediaStream from host and add it to the video */
 196     let hostMessage = JSON.parse(msg.data)
 197     console.log('Client: Renego')
 198     cpc.setRemoteDescription(hostMessage.sdp).then(() => {
 199       cpc.createAnswer().then((answer) => {
 200         return cpc.setLocalDescription(answer)
 201       }).then(() => {
 202         dataChannel.send(JSON.stringify({
 203           "cmd": "> screen dataChannel",
 204           "sdp": cpc.localDescription
 205         }))
 206       })
 207     })
 208
 209
 210   }
 211   dataChannel.onopen = () => {
 212     document.body.innerHTML = (`<div><button> Connection with host established! </button></div> <video controls></video>`)
 213   }
 214
 215 })
 216 document.addEventListener('DOMContentLoaded', () => {
 217
 218   document.body.innerHTML = `<button> Setting up connection with host  </button>`
 219
 220 });