socket.io/lib/socket.js

/**
 * Socket.IO client
 * 
 * @author Guillermo Rauch <guillermo@learnboost.com>
 * @license The MIT license.
 * @copyright Copyright (c) 2010 LearnBoost <dev@learnboost.com>
 */

(function(){
  var io = this.io;
  
  var Socket = io.Socket = function(host, options){
    this.host = host || document.domain;
    this.options = {
      secure: false,
      document: document,
      port: document.location.port || 80,
      resource: 'socket.io',
      transports: ['websocket', 'flashsocket', 'htmlfile', 'xhr-multipart', 'xhr-polling', 'jsonp-polling'],
      transportOptions: {
        'xhr-polling': {
          timeout: 25000 // based on polling duration default
        },
        'jsonp-polling': {
          timeout: 25000
        }
      },
      connectTimeout: 5000,
      reconnect: true,
      reconnectionDelay: 500,
      maxReconnectionAttempts: 10,
      tryTransportsOnConnectTimeout: true,
      rememberTransport: true
    };
    io.util.merge(this.options, options);
    this.connected = false;
    this.connecting = false;
    this.events = {};
    this.transport = this.getTransport();
    if (!this.transport && 'console' in window) console.error('No transport available');
  };
  
  Socket.prototype.getTransport = function(override){
    var transports = override || this.options.transports, match;
    if (this.options.rememberTransport && !override){
      match = this.options.document.cookie.match('(?:^|;)\\s*socketio=([^;]*)');
      if (match){
        this.rememberedTransport = true;
        transports = [decodeURIComponent(match[1])];
      }
    } 
    for (var i = 0, transport; transport = transports[i]; i++){
      if (io.Transport[transport] 
        && io.Transport[transport].check() 
        && (!this.isXDomain() || io.Transport[transport].xdomainCheck())){
        return new io.Transport[transport](this, this.options.transportOptions[transport] || {});
      }
    }
    return null;
  };
  
  Socket.prototype.connect = function(fn){
    if (this.transport && !this.connected){
      if (this.connecting) this.disconnect(true);
      this.connecting = true;
      this.emit('connecting', [this.transport.type]);
      this.transport.connect();
      if (this.options.connectTimeout){
        var self = this;
        this.connectTimeoutTimer = setTimeout(function(){
          if (!self.connected){
            self.disconnect(true);
            if (self.options.tryTransportsOnConnectTimeout && !self.rememberedTransport){
              if(!self.remainingTransports) self.remainingTransports = self.options.transports.slice(0);
              var transports = self.remainingTransports;
              while(transports.length > 0 && transports.splice(0,1)[0] != self.transport.type){}
              if(transports.length){
                self.transport = self.getTransport(transports);
                self.connect();
              }
            }
            if(!self.remainingTransports || self.remainingTransports.length == 0) self.emit('connect_failed');
          }
          if(self.remainingTransports && self.remainingTransports.length == 0) delete self.remainingTransports;
        }, this.options.connectTimeout);
      }
    }
    if (fn && typeof fn == 'function') this.once('connect',fn);
    return this;
  };
  
  Socket.prototype.send = function(data){
    if (!this.transport || !this.transport.connected) return this.queue(data);
    this.transport.send(data);
    return this;
  };
  
  Socket.prototype.disconnect = function(reconnect){
    if (this.connectTimeoutTimer) clearTimeout(this.connectTimeoutTimer);
    if (!reconnect) this.options.reconnect = false;
    this.transport.disconnect();
    return this;
  };
  
  Socket.prototype.on = function(name, fn){
    if (!(name in this.events)) this.events[name] = [];
    this.events[name].push(fn);
    return this;
  };
  
  Socket.prototype.once = function(name, fn){
    var self = this
      , once = function(){
        self.removeEvent(name, once);
        fn.apply(self, arguments);
      };
    once.ref = fn;
    self.on(name, once);
    return this;
  };
  
  Socket.prototype.emit = function(name, args){
    if (name in this.events){
      var events = this.events[name].concat();
      for (var i = 0, ii = events.length; i < ii; i++)
        events[i].apply(this, args === undefined ? [] : args);
    }
    return this;
  };

  Socket.prototype.removeEvent = function(name, fn){
    if (name in this.events){
      for (var a = 0, l = this.events[name].length; a < l; a++)
        if (this.events[name][a] == fn || this.events[name][a].ref && this.events[name][a].ref == fn) this.events[name].splice(a, 1);    
    }
    return this;
  };
  
  Socket.prototype.queue = function(message){
    if (!('queueStack' in this)) this.queueStack = [];
    this.queueStack.push(message);
    return this;
  };
  
  Socket.prototype.doQueue = function(){
    if (!('queueStack' in this) || !this.queueStack.length) return this;
    this.transport.send(this.queueStack);
    this.queueStack = [];
    return this;
  };
  
  Socket.prototype.isXDomain = function(){
    var locPort = window.location.port || 80;
    return this.host !== document.domain || this.options.port != locPort;
  };
  
  Socket.prototype.onConnect = function(){
    this.connected = true;
    this.connecting = false;
    this.doQueue();
    if (this.options.rememberTransport) this.options.document.cookie = 'socketio=' + encodeURIComponent(this.transport.type);
    this.emit('connect');
  };
  
  Socket.prototype.onMessage = function(data){
    this.emit('message', [data]);
  };
  
  Socket.prototype.onDisconnect = function(){
    var wasConnected = this.connected;
    this.connected = false;
    this.connecting = false;
    this.queueStack = [];
    if (wasConnected){
      this.emit('disconnect');
      if (this.options.reconnect && !this.reconnecting) this.onReconnect();
    }
  };
  
  Socket.prototype.onReconnect = function(){
    this.reconnecting = true;
    this.reconnectionAttempts = 0;
    this.reconnectionDelay = this.options.reconnectionDelay;
    
    var self = this
      , tryTransportsOnConnectTimeout = this.options.tryTransportsOnConnectTimeout
      , rememberTransport = this.options.rememberTransport;
    
    function reset(){
      if(self.connected) self.emit('reconnect',[self.transport.type,self.reconnectionAttempts]);
      self.removeEvent('connect_failed', maybeReconnect).removeEvent('connect', maybeReconnect);
      delete self.reconnecting;
      delete self.reconnectionAttempts;
      delete self.reconnectionDelay;
      delete self.reconnectionTimer;
      delete self.redoTransports;
      self.options.tryTransportsOnConnectTimeout = tryTransportsOnConnectTimeout;
      self.options.rememberTransport = rememberTransport;
      
      return;
    };
    
    function maybeReconnect(){
      if (!self.reconnecting) return;
      if (!self.connected){
        if (self.connecting && self.reconnecting) return self.reconnectionTimer = setTimeout(maybeReconnect, 1000);
        
        if (self.reconnectionAttempts++ >= self.options.maxReconnectionAttempts){
          if (!self.redoTransports){
            self.on('connect_failed', maybeReconnect);
            self.options.tryTransportsOnConnectTimeout = true;
            self.transport = self.getTransport(self.options.transports); // overwrite with all enabled transports
            self.redoTransports = true;
            self.connect();
          } else {
            self.emit('reconnect_failed');
            reset();
          }
        } else {
          self.reconnectionDelay *= 2; // exponential backoff
          self.connect();
          self.emit('reconnecting', [self.reconnectionDelay,self.reconnectionAttempts]);
          self.reconnectionTimer = setTimeout(maybeReconnect, self.reconnectionDelay);
        }
      } else {
        reset();
      }
    };
    this.options.tryTransportsOnConnectTimeout = false;
    this.reconnectionTimer = setTimeout(maybeReconnect, this.reconnectionDelay);
    
    this.on('connect', maybeReconnect);
  };

  Socket.prototype.fire = Socket.prototype.emit;
  Socket.prototype.addListener = Socket.prototype.addEvent = Socket.prototype.addEventListener = Socket.prototype.on;
  Socket.prototype.removeListener = Socket.prototype.removeEventListener = Socket.prototype.removeEvent;
  
})();