primus-socket.io-client

This is a fork of the original Socket.IO client's 0.9 codebase. We've forked it to provide additional stability fixes. One of the main reasons we still maintain this fork is that using Socket.IO 1.0 inside of Primus doesn't make sense as Socket.IO 1.0 is just a wrapper around Engine.IO so it makes more sense for our users to use our engine.io transformer instead of supporting Socket.IO 1.0.

Sockets for the rest of us

The socket.io client is basically a simple HTTP Socket interface implementation. It looks similar to WebSocket while providing additional features and leveraging other transports when WebSocket is not supported by the user's browser.

var socket = io.connect('http://domain.com');
socket.on('connect', function () {
  // socket connected
});
socket.on('custom event', function () {
  // server emitted a custom event
});
socket.on('disconnect', function () {
  // socket disconnected
});
socket.send('hi there');

Recipes

Utilizing namespaces (ie: multiple sockets)

If you want to namespace all the messages and events emitted to a particular endpoint, simply specify it as part of the connect uri:

var chat = io.connect('http://localhost/chat');
chat.on('connect', function () {
  // chat socket connected
});

var news = io.connect('/news'); // io.connect auto-detects host
news.on('connect', function () {
  // news socket connected
});

Emitting custom events

To ease with the creation of applications, you can emit custom events outside of the global message event.

var socket = io.connect();
socket.emit('server custom event', { my: 'data' });

Forcing disconnection

var socket = io.connect();
socket.on('connect', function () {
  socket.disconnect();
});

Documentation

io#connect

io.connect(uri, [options]);

Options:

• resource

  socket.io

  The resource is what allows the socket.io server to identify incoming connections by socket.io clients. In other words, any HTTP server can implement socket.io and still serve other normal, non-realtime HTTP requests.

• transports

['websocket', 'flashsocket', 'htmlfile', 'xhr-multipart', 'xhr-polling', 'jsonp-polling']

A list of the transports to attempt to utilize (in order of preference).

• 'connect timeout'

5000

The amount of milliseconds a transport has to create a connection before we consider it timed out.

• 'try multiple transports'

true

A boolean indicating if we should try other transports when the connectTimeout occurs.

• reconnect

true

A boolean indicating if we should automatically reconnect if a connection is disconnected.

• 'reconnection delay'

500

The amount of milliseconds before we try to connect to the server again. We are using a exponential back off algorithm for the following reconnections, on each reconnect attempt this value will get multiplied (500 > 1000 > 2000 > 4000 > 8000).

• 'max reconnection attempts'

10

The amount of attempts should we make using the current transport to connect to the server? After this we will do one final attempt, and re-try with all enabled transport methods before we give up.

Properties:

• options

  The passed in options combined with the defaults.

• connected

  Whether the socket is connected or not.

• connecting

  Whether the socket is connecting or not.

• reconnecting

  Whether we are reconnecting or not.

• transport

  The transport instance.

Methods:

• connect(λ)

  Establishes a connection. If λ is supplied as argument, it will be called once the connection is established.

• send(message)

  A string of data to send.

• disconnect

  Closes the connection.

• on(event, λ)

  Adds a listener for the event event.

• once(event, λ)

  Adds a one time listener for the event event. The listener is removed after the first time the event is fired.

• removeListener(event, λ)

  Removes the listener λ for the event event.

Events:

• connect

  Fired when the connection is established and the handshake successful.

• connecting(transport_type)

  Fired when a connection is attempted, passing the transport name.

• connect_failed

  Fired when the connection timeout occurs after the last connection attempt. This only fires if the connectTimeout option is set. If the tryTransportsOnConnectTimeout option is set, this only fires once all possible transports have been tried.

• message(message)

  Fired when a message arrives from the server

• close

  Fired when the connection is closed. Be careful with using this event, as some transports will fire it even under temporary, expected disconnections (such as XHR-Polling).

• disconnect

  Fired when the connection is considered disconnected.

• reconnect(transport_type,reconnectionAttempts)

  Fired when the connection has been re-established. This only fires if the reconnect option is set.

• reconnecting(reconnectionDelay,reconnectionAttempts)

  Fired when a reconnection is attempted, passing the next delay for the next reconnection.

• reconnect_failed

  Fired when all reconnection attempts have failed and we where unsuccessful in reconnecting to the server.

Contributors

Guillermo Rauch <guillermo@learnboost.com>

Arnout Kazemier <info@3rd-eden.com>

License

MIT