socket.js

/**
 * Module dependencies.
 */

var Emitter = require('events').EventEmitter
  , parser = require('socket.io-parser')
  , debug = require('debug')('socket.io:socket');

/**
 * Module exports.
 */

module.exports = exports = Socket;

/**
 * Blacklisted events.
 *
 * @api public
 */

exports.events = [
  'error',
  'connect',
  'disconnect',
  'newListener'
];

/**
 * Flags.
 *
 * @api public
 */

exports.flags = [
  'json',
  'volatile',
  'broadcast'
];

/**
 * `EventEmitter#emit` reference.
 */

var emit = Emitter.prototype.emit;

/**
 * Interface to a `Client` for a given `Namespace`.
 *
 * @param {Namespace} nsp
 * @param {Client} client
 * @api public
 */

function Socket(nsp, client){
  this.nsp = nsp;
  this.server = nsp.server;
  this.adapter = this.nsp.adapter;
  this.id = client.id;
  this.request = client.request;
  this.client = client;
  this.rooms = [];
  this.acks = {};
  this.connected = true;
  this.disconnected = false;
}

/**
 * Inherits from `EventEmitter`.
 */

Socket.prototype.__proto__ = Emitter.prototype;

/**
 * Apply flags from `Socket`.
 */

exports.flags.forEach(function(flag){
  Socket.prototype.__defineGetter__(flag, function(){
    this.flags = this.flags || {};
    this.flags[flag] = true;
    return this;
  });
});

/**
 * Emits to this client.
 *
 * @return {Socket} self
 * @api public
 */

Socket.prototype.emit = function(ev){
  if (~exports.events.indexOf(ev)) {
    emit.apply(this, arguments);
  } else {
    // set up packet object
    var args = Array.prototype.slice.call(arguments);
    var packet = { type: parser.EVENT, data: args };

    // access last argument to see if it's an ACK callback
    if ('function' == typeof args[args.length - 1]) {
      if (this._rooms || (this.flags && this.flags.broadcast)) {
        throw new Error('Callbacks are not supported when broadcasting');
      }

      debug('emitting packet with ack id %d', this.nsp.ids);
      this.acks[this.nsp.ids] = args.pop();
      packet.id = this.nsp.ids++;
    }

    if (this._rooms || (this.flags && this.flags.broadcast)) {
      this.adapter.broadcast(packet, {
        except: [this.id],
        rooms: this._rooms,
        flags: this.flags
      });
    } else {
      // dispatch packet
      this.packet(packet);
    }

    // reset flags
    delete this._rooms;
    delete this.flags;
  }
  return this;
};

/**
 * Targets a room when broadcasting.
 *
 * @param {String} name
 * @return {Socket} self
 * @api public
 */

Socket.prototype.to =
Socket.prototype.in = function(name){
  this._rooms = this._rooms || [];
  if (!~this._rooms.indexOf(name)) this._rooms.push(name);
  return this;
};

/**
 * Sends a `message` event.
 *
 * @return {Socket} self
 * @api public
 */

Socket.prototype.send =
Socket.prototype.write = function(){
  var args = Array.prototype.slice.call(arguments);
  args.unshift('message');
  this.emit.apply(this, args);
  return this;
};

/**
 * Writes a packet.
 *
 * @param {Object} packet object
 * @api private
 */

Socket.prototype.packet = function(packet){
  packet.nsp = this.nsp.name;
  this.client.packet(packet);
};

/**
 * Joins a room.
 *
 * @param {String} room
 * @param {Function} optional, callback
 * @return {Socket} self
 * @api private
 */

Socket.prototype.join = function(room, fn){
  debug('joining room %s', room);
  var self = this;
  if (~this.rooms.indexOf(room)) return this;
  this.adapter.add(this.id, room, function(err){
    if (err) return fn && fn(err);
    debug('joined room %s', room);
    self.rooms.push(room);
    fn && fn(null);
  });
  return this;
};

/**
 * Leaves a room.
 *
 * @param {String} room
 * @param {Function} optional, callback
 * @return {Socket} self
 * @api private
 */

Socket.prototype.leave = function(room, fn){
  debug('leave room %s', room);
  var self = this;
  this.adapter.del(this.id, room, function(err){
    if (err) return fn && fn(err);
    debug('left room %s', room);
    self.rooms.splice(self.rooms.indexOf(room, 1));
    fn && fn(null);
  });
  return this;
};

/**
 * Leave all rooms.
 *
 * @api private
 */

Socket.prototype.leaveAll = function(){
  this.adapter.delAll(this.id);
};

/**
 * Called by `Namespace` upon succesful
 * middleware execution (ie: authorization).
 *
 * @api private
 */

Socket.prototype.onconnect = function(){
  debug('socket connected - writing packet');
  this.join(this.id);
  this.packet({ type: parser.CONNECT });
  this.nsp.connected[this.id] = this;
};

/**
 * Called with each packet. Called by `Client`.
 *
 * @param {Object} packet
 * @api private
 */

Socket.prototype.onpacket = function(packet){
  debug('got packet %j', packet);
  switch (packet.type) {
    case parser.EVENT:
      this.onevent(packet);
      break;

    case parser.ACK:
      this.onack(packet);
      break;

    case parser.DISCONNECT:
      this.ondisconnect();
      break;

    case parser.ERROR:
      this.emit('error', packet.data);
  }
};

/**
 * Called upon event packet.
 *
 * @param {Object} packet object
 * @api private
 */

Socket.prototype.onevent = function(packet){
  var args = packet.data || [];
  debug('emitting event %j', args);

  if (null != packet.id) {
    debug('attaching ack callback to event');
    args.push(this.ack(packet.id));
  }

  emit.apply(this, args);
};

/**
 * Produces an ack callback to emit with an event.
 *
 * @param {Number} packet id
 * @api private
 */

Socket.prototype.ack = function(id){
  var self = this;
  var sent = false;
  return function(){
    // prevent double callbacks
    if (sent) return;
    var args = Array.prototype.slice.call(arguments);
    debug('sending ack %j', args);
    self.packet({
      id: id,
      type: parser.ACK,
      data: args
    });
  };
};

/**
 * Called upon ack packet.
 *
 * @api private
 */

Socket.prototype.onack = function(packet){
  var ack = this.acks[packet.id];
  if ('function' == typeof ack) {
    debug('calling ack %s with %j', packet.id, packet.data);
    ack.apply(this, packet.data);
    delete this.acks[packet.id];
  } else {
    debug('bad ack %s', packet.id);
  }
};

/**
 * Called upon client disconnect packet.
 *
 * @api private
 */

Socket.prototype.ondisconnect = function(){
  debug('got disconnect packet');
  this.onclose('client namespace disconnect');
};

/**
 * Called upon closing. Called by `Client`.
 *
 * @param {String} reason
 * @api private
 */

Socket.prototype.onclose = function(reason){
  if (!this.connected) return this;
  debug('closing socket - reason %s', reason);
  this.leaveAll();
  this.nsp.remove(this);
  this.client.remove(this);
  this.connected = false;
  this.disconnected = true;
  delete this.nsp.connected[this.id];
  this.emit('disconnect', reason);
};

/**
 * Produces an `error` packet.
 *
 * @param {Object} error object
 * @api private
 */

Socket.prototype.error = function(err){
  this.packet({ type: parser.ERROR, data: err });
};

/**
 * Disconnects this client.
 *
 * @param {Boolean} if `true`, closes the underlying connection
 * @return {Socket} self
 * @api public
 */

Socket.prototype.disconnect = function(close){
  if (!this.connected) return this;
  if (close) {
    this.client.disconnect();
  } else {
    this.packet({ type: parser.DISCONNECT });
    this.onclose('server namespace disconnect');
  }
  return this;
};