bittychat/client.html at master · timbauman/bittychat · GitHub

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<html><head>
<style>
* {font-family: "Lucida Console", Monaco, monospace; font-size: 14px;}
input { font-size: 12px; line-height: 14px;}
textarea {width:500px;height:300px;}
div, form { display: none; }
</style>
  <script src="https://crypto.stanford.edu/sjcl/sjcl.js"></script>
<title>bitty chat</title>
</head>
<body>
  <div id="about"><a href="http://timbauman.github.io/bittychat/">about bitty chat</a></div>
  <div id="starting"><button id="new_button">new chat</button> or <input id="remote_code" type="text" placeholder="insert code here" /> <button id="load_button">load existing chat</button></div>
  <div id="sharing">
    share this URL <input type="text" disabled="disabled" id="url" placeholder="loading..." />
    or this code <input type="text" disabled="disabled" id="code" placeholder="loading..." /><br />
  </div>
  <div id="connecting">waiting for connection...</div>
  <form id="chatform">
    message: <input type="text" id="message" /><button id="sendButton" type="submit">Send</button><br />
    <textarea id="chatbox" disabled="disabled"></textarea>
  </form>
  <div id="closed">connection lost...</div>
<script>

/* config */
/* brokers chat connections - untrusted */
var URL = 'http://localhost:8000/';

/* stun server */
var servers = {
  iceServers: [{ 'url': 'stun:stun.l.google.com:19302' }]
};

/* WebRTC compatability */
var RTCPeerConnection = null;
var getUserMedia = null;
var attachMediaStream = null;
var reattachMediaStream = null;
var webrtcDetectedBrowser = null;

if (navigator.mozGetUserMedia) {

  webrtcDetectedBrowser = "firefox";

  RTCPeerConnection = mozRTCPeerConnection;

  RTCSessionDescription = mozRTCSessionDescription;

  RTCIceCandidate = mozRTCIceCandidate;
} else if (navigator.webkitGetUserMedia) {

  webrtcDetectedBrowser = "chrome";

  RTCPeerConnection = webkitRTCPeerConnection;

} else {
  document.body.innerHTML = "your browser doesn't appear to support WebRTC...";
}

performance.now = performance.now || performance.webkitNow;

/* the code */

var options = {
  optional: [{ RtpDataChannels: true }]
};

var description = null;
var cands = [];
var sendButton = document.getElementById('sendButton');
var form = document.getElementById('chatform');
var startDiv = document.getElementById('starting');
var sharingDiv = document.getElementById('sharing');
var connectingDiv = document.getElementById('connecting');
document.getElementById('about').style.display = 'block';

var channel;
sendButton.disabled = true;

var k='';
var id='';
var d={};
var pc1 = new RTCPeerConnection(servers, options);
pc1.onicecandidate = function(event) {
  if (event.candidate) {
    cands.push(event.candidate);
  }
};
channel = pc1.createDataChannel("sendDataChannel",
                                       {reliable: false});
channel.onmessage = onReceiveMessageCallback;
channel.onopen = onOpen;
channel.onclose = onClose;

form.onsubmit = send;

if (k === '') {
  /* set url*/
  startDiv.style.display = 'block';
} else {
  connectingDiv.style.display = 'block';
  receiveOffer(d);
}

document.getElementById('new_button').onclick = function() {
  generateKeys();
  pc1.createOffer(createdDesc); /* make offer */
  startDiv.style.display = 'none';
  sharingDiv.style.display = 'block';
};
document.getElementById('load_button').onclick = function() {
  d = JSON.parse(document.getElementById('remote_code').value);
  k = d.k;
  id = d.id;
  receiveOffer(d.d);
};


function generateKeys() {
  if (!pc1.localDescription) {
    /* not sure if this is secure but it keeps shuffling the key until it gets an offer */
    id = sjcl.random.randomWords(1,9)[0].toString();
  }
}


function receiveOffer(d) {
  console.log(d);
  if (d.desc && d.peers) {
    pc1.setRemoteDescription(new RTCSessionDescription(d.desc));
    var peers = d.peers;
    console.log(peers);
    for (var i = 0; i < peers.length; i++) {
      var peer = peers[i];
      var cand = new RTCIceCandidate(peer);
      pc1.addIceCandidate(cand);
    }
    sharingDiv.style.display = 'none';
    startDiv.style.display = 'none';
    connectingDiv.style.display = 'block';
  }
  if (!pc1.localDescription) {
    /* we must respond */
    pc1.createAnswer(createdDesc);
    console.log('responding with answer');
  }
}


function send() {
  var msg = document.getElementById('message');
  var m = msg.value;
  channel.send(m);
  console.log(m);
  document.getElementById('chatbox').value += 'me: ' + m + '\n';
  msg.value = '';
  msg.focus();
  return false;
}


window.onbeforeunload = function() {
  channel.close();
  pc1.close();
  pc1 = null;
  sendButton.disabled = true;
  dataChannelSend.value = "";
  dataChannelReceive.value = "";
};

function createdDesc(desc) {
  pc1.setLocalDescription(desc);
  if (cands.length == 0) {
    setTimeout(function() { createdDesc(desc); }, 2000);
    return;
  }
  console.log('description');
  var j = JSON.stringify({desc: desc, peers: cands});
  console.log(pc1.remoteDescription);
  if (pc1.remoteDescription) {
    var offer = sjcl.encrypt(k, j + JSON.stringify(sjcl.hash.sha256.hash(j)));
    console.log(offer);
    sendOffer(offer);
  } else {
    /* set the key! */
    m = (/AES_CM_128_HMAC_SHA1_80 inline:(\S+)/).exec(desc.sdp);
    k = m[1];
    /* The ([^)]) prevents us from matching the regular expressions */
    document.getElementById('url').value =
      'data:text/html;,'
        + document.documentElement.innerHTML
            .replace(/([^)])k=(''|"")(\W)/, "$1k='" + k + "'$3")
            .replace(/([^)])id=(''|"")(\W)/, "$1id='" + id + "'$3")
            .replace(/([^)])d={}(\W)/, "$1d=" + j + "$2");
    document.getElementById('code').value = JSON.stringify({k:k,id:id,d:{desc: desc, peers: cands}});
    /* begin polling for offers */
    listenForOffers();
  }
}

function sendOffer(offer) {
  var req = new XMLHttpRequest();
  req.open("get", URL + '?k=' + encodeURIComponent(id) + '&v=' + encodeURIComponent(offer), true);
  req.send();
  connectingDiv.style.display = 'block';
}

function heardOffer(data) {
  if (data && data.trim()) {
    var decrypted = sjcl.decrypt(k, data);
    hash = JSON.parse(decrypted.substring(decrypted.lastIndexOf('[')));
    j = decrypted.substring(0, decrypted.lastIndexOf('['));
    if (hash.toString() === sjcl.hash.sha256.hash(j).toString()) {
      o = JSON.parse(j);
      receiveOffer(o);
    }
  }
}

function listenForOffers() {
  /* this may take many forms! perhaps in the future we will use something kewler than json */
  if (!pc1.remoteDescription) {
    connectingDiv.style.display = 'block';
    var req = new XMLHttpRequest();
    req.onload = function(e) {
      heardOffer(req.responseText);
    };
    req.open("get", URL + '?k=' + encodeURIComponent(id), true);
    req.send();
    setTimeout(listenForOffers, 2000);
  }
}

function onReceiveMessageCallback(event) {
  document.getElementById('chatbox').value += 'them: ' + event.data + '\n';
}

function onOpen() {
  var readyState = channel.readyState;
  sendButton.disabled = readyState !== "open";
  if (!sendButton.disabled) {
    document.title += ' - ' + id;
    form.style.display = 'block';
    connectingDiv.style.display = 'none';
  }
}

function onClose() {
  form.style.display = 'none';
  document.getElementById('closed').style.display = 'block';
}
</script>
</body></html>