function Babel(username) {Babel is an open source chat widget and API built with the PubNub Global Realtime Network. Babel let’s you send encrypted, self-destructing messages and also helps facilitate public key exchange.
You can check out the demo right here, or view the source on Github.
function Babel(username) {The name of the PubNub channel we will be using. Change this if you want to use a different channel.
var channel = "babel";Generate an RSA key and grab the public key.
var RSAkey = cryptico.generateRSAKey(1024);
var publicKey = cryptico.publicKeyString(RSAkey);An object which contains your username and public key. It will be given to other users.
var myUser = {
username: username,
publicKey: publicKey
};A mapping of all currently connected users’ usernames to their public keys.
var users = {};A mapping of usernames and the messages they’ve sent. (Messages you’ve sent are mapped by the the username of the reciever)
var messages = {};receiveMessage and presenceChange are called when a message
intended for the user is received and when someone connects to
or leaves the PubNub channel respectively. Both methods can be changed
by the publicly accessible methods onMessage and onPresence.
var receiveMessage = function(){};
var presenceChange = function(){};messageHandler is called whenever a message is received.
If the recipient of the message is this user, it will decrypt
and store the message inside the messages object,
then call receiveMessage with the decrypted message.
var messageHandler = function (msg) {
if (msg.recipient === username) {
var plaintext = cryptico.decrypt(msg.message.cipher, RSAkey).plaintext;
parsedMsg = {
msgID: msg.msgID,
plaintext: plaintext,
TTL: msg.ttl,
sender: msg.sender,
recipient: msg.recipient
};
if (messages[msg.sender] === undefined) {
messages[msg.sender] = [parsedMsg];
} else {
messages[msg.sender].push(parsedMsg);
}
receiveMessage(parsedMsg);
deleteMessage(msg.sender, msg.msgID, msg.ttl);
}
};presenceHandler is called whenever a user leaves, joins, or
times out of Babel. After updating our users object, it calls
presenceChange().
var presenceHandler = function (msg) {A user has joined Babel, so we add them to our users object.
if (msg.action === "join" || msg.action === "state-change") {If the presence message contains data aka state, add this to our users object.
if ("data" in msg) {
users[msg.data.username] = msg.data.publicKey;
}Otherwise, we have to call here_now to get the state of the new subscriber to the channel.
else {
pubnub.here_now({
channel: channel,
state: true,
callback: herenowUpdate
});
}
presenceChange();
}A user has left or timed out of Babel so we remove them from our users object.
else if (msg.action === "timeout" || msg.action === "leave") {
delete users[msg.uuid];
presenceChange();
}
};Initialize PubNub.
var pubnub = PUBNUB.init({You can replace demo with your own PubNub publish and subscribe keys.
publish_key: 'demo',
subscribe_key: 'demo',
uuid: username,
ssl: true,
});Subscribe to our PubNub channel.
pubnub.subscribe({
channel: channel,
callback: messageHandler,
presence: presenceHandler,Set our state to our user object, which contains our username and public key.
state: myUser,
});herenowUpdate is only called as a callback to ‘here_now’.
It does a complete update of our users object and then
calls presenceChange().
var herenowUpdate = function (msg) {
users = {};
for (var i = 0; i < msg.uuids.length; i++) {
if ("state" in msg.uuids[i]) {
users[msg.uuids[i].state.username] = msg.uuids[i].state.publicKey;
}
}
presenceChange();
};Delete a message from the messages object, after TTL seconds.
(If you sent the message, username is the username of the recipient.
If you received the message, username is the username of the sender.)
var deleteMessage = function (username, msgID, TTL) {
setTimeout(function() {
if (username === msgID) {
for (var i = 0; i < messages[username].length; i++) {
if (messages[username][i].msgID === msgID) {
messages[username].splice(i, 1);
break;
}
}
}
}, 1000*TTL);
}; return {Sends message to recipient. After ttl seconds, the message
will self-destruct, and neither you or the recipient will be able
to retrieve the message from your messages object.
sendMessage: function (recipient, message, ttl) {
if (recipient in users) {
var plaintext = message;
var recipient_key = users[recipient];
message = cryptico.encrypt(message, recipient_key);
pubnub.uuid(function (msgID) {
pubnub.publish({
channel: channel,
message: {
recipient: recipient,
msgID: msgID,
sender: username,
message: message,
ttl: ttl
},
callback: function () {
parsedMsg = {
msgID: msgID,
plaintext: plaintext,
TTL: ttl,
sender: username,
recipient: recipient
};
if (messages[recipient] === undefined) {
messages[recipient] = [parsedMsg];
} else {
messages[recipient].push(parsedMsg);
}
receiveMessage(parsedMsg);
deleteMessage(recipient, msgID, ttl);
}
});
});
}
},Changes the function that is called when you are sent a message or when you send a message.
An argument of this form is passed to the callback.
{msgID: "487f703e-3189-4f66-87a1-62cb0ffb52fd",
plaintext: "very example message", TTL: 5, sender: "doge",
recipient: "shibe"}
onMessage: function (callback) {
receiveMessage = callback;
},Change the function that is called when a user joins, leaves, or times out of Babel. No arguments are passed to the callback.
onPresence: function (callback) {
presenceChange = callback;
},Returns a mapping of all usernames and their respective public keys.
listUsers: function () {
return users;
},Returns a mapping of usernames and the messages they’ve sent. (Messages you’ve sent are mapped by the the username of the reciever)
returnMessages: function () {
return messages;
}, myKey: function () {
return RSAkey;
},Quits Babel. Other users will no longer be able to retrieve your public key or send messages to you.
quit: function () {
pubnub.unsubscribe({
channel: channel
});
}
};
}