Migrating to 1.0

This will explain the main differences between 0.9x and 1.0, and should help ease the migration process. It's gonna rule!!

Authentication differences

Socket.io uses middleware now

You can give a Socket.io server arbitrary functions via io.use() that are run when a socket is created. Check out this example:

var srv = http();
var sio = require('socket.io')(srv);
var run = 0;
sio.use(function(socket, next){
  run++; // 0 -> 1
  next();
});
sio.use(function(socket, next) {
  run++; // 1 -> 2
  next();
});
var socket = require('socket.io-client')();
socket.on('connect', function(){
  // run == 2 here
});

... so its cleaner to do auth via middleware now

The old io.set() and io.get() methods are deprecated and only supported for backwards compatibility. Here is a translation of an old authorization example into middleware-style.

io.set('authorization', function (handshakeData, callback) {
  // make sure the handshake data looks good
  callback(null, true); // error first, 'authorized' boolean second 
});

vs.

this.use(function(socket, next) {
  var handshakeData = socket.request;
  // make sure the handshake data looks good as before
  // if error do this:
    // next(new Error('not authorized');
  // else just call next
  next();
});

Log differences

Logging is now based on debug

To print all debug logging, set the environment variable DEBUG to *. ie: DEBUG=* node index.js

To print only socket.io related logging: DEBUG=socket.io:* node index.js.

To print logging only from the socket object: DEBUG=socket.io:socket node index.js.

This pattern should hopefully be making sense at this point. The names of the files in socket.io/lib are equivalent to their debug names.

Debug also works in the browser; logs are persisted to localstorage. To use: open the developer console and type debug.enable('socket.io:*') (or any debug level) and then refresh the page. Everything is logged until you run debug.disable().

See more at the debug documentation here.

Broadcasting differences

Broadcasting to all clients in default namespace

Previously we had:

io.sockets.emit('eventname', 'eventdata');

Now we have:

io.emit('eventname', 'eventdata');

Neat. In both cases, these messages reach all clients connected to the default '/' namespace, but not clients in other namespaces. The older version still works but this is nice shortcut.

Configuration differences

Fill this in later

Parser / Protocol differences

This is only relevant for updating things like socket.io implementations in other languages, custom socket.io clients, etc.

Difference 1 - packet encoding

Parsing is now class based and asynchronous. Instead of returning a single encoded string, encode calls callback with an array of encodings as the only argument. Each encoding should be written to the transport in order. This is more flexible and makes binary data transport work. Here's an example:

var encoding = parser.encode(packet);
console.log(encoding); // fully encoded packet

vs.

var encoder = new parser.Encoder();
encoder.encode(packet, function(encodings) {
  for (var i = 0; i < encodings.length; i++) {
    console.log(encodings[i]); // encoded parts of the packet
  }
});

Difference 2 - packet decoding

Decoding takes things a step further and is event-based. This is done because some objects (binary-containing) are both encoded and decoded in multiple parts. This example should help:

var packet = parser.decode(decoding);
console.log(packet); // formed socket.io packet to handle

vs.

var decoder = new parser.Decoder();
decoder.on('decoded', function(packet) {
  console.log(packet); // formed socket.io packet to handle
});
decoder.add(encodings[0]); // say encodings is array of two encodings received from transport
decoder.add(encodings[1]); // after adding the last element, 'decoded' is emitted from decoder