socket.io/lib/transports/flashsocket.js

/**
 * Module dependencies.
 */

var WS = require('./websocket');
var util = require('../util');
var debug = require('debug')('engine.io-client:flashsocket');

/**
 * Module exports.
 */

module.exports = FlashWS;

/**
 * Global reference.
 */

var global = require('global');

/**
 * Obfuscated key for Blue Coat.
 */

var xobject = global[['Active'].concat('Object').join('X')];

/**
 * FlashWS constructor.
 *
 * @api public
 */

function FlashWS(options){
  WS.call(this, options);
  this.flashPath = options.flashPath;
  this.policyPort = options.policyPort;
}

/**
 * Inherits from WebSocket.
 */

util.inherits(FlashWS, WS);

/**
 * Transport name.
 *
 * @api public
 */

FlashWS.prototype.name = 'flashsocket';

/*
 * FlashSockets only support binary as base64 encoded strings
 */

FlashWS.prototype.supportsBinary = false;

/**
 * Opens the transport.
 *
 * @api public
 */

FlashWS.prototype.doOpen = function(){
  if (!this.check()) {
    // let the probe timeout
    return;
  }

  // instrument websocketjs logging
  function log(type){
    return function(){
      var str = Array.prototype.join.call(arguments, ' ');
      debug('[websocketjs %s] %s', type, str);
    };
  }

  global.WEB_SOCKET_LOGGER = { log: log('debug'), error: log('error') };
  global.WEB_SOCKET_SUPPRESS_CROSS_DOMAIN_SWF_ERROR = true;
  global.WEB_SOCKET_DISABLE_AUTO_INITIALIZATION = true;

  if (!global.WEB_SOCKET_SWF_LOCATION) {
    global.WEB_SOCKET_SWF_LOCATION = this.flashPath + 'WebSocketMainInsecure.swf';
  }

  // dependencies
  var deps = [this.flashPath + 'web_socket.js'];

  if (!global.swfobject) {
    deps.unshift(this.flashPath + 'swfobject.js');
  }

  var self = this;

  load(deps, function(){
    self.ready(function(){
      WebSocket.__addTask(function () {
        self.ws = new WebSocket(self.uri());
        self.addEventListeners();
      });
    });
  });
};

/**
 * Override to prevent closing uninitialized flashsocket.
 *
 * @api private
 */

FlashWS.prototype.doClose = function(){
  if (!this.ws) return;
  var self = this;
  WebSocket.__addTask(function(){
    WS.prototype.doClose.call(self);
  });
};

/**
 * Writes to the Flash socket.
 *
 * @api private
 */

FlashWS.prototype.write = function(){
  var self = this, args = arguments;
  WebSocket.__addTask(function(){
    WS.prototype.write.apply(self, args);
  });
};

/**
 * Called upon dependencies are loaded.
 *
 * @api private
 */

FlashWS.prototype.ready = function(fn){
  if (typeof WebSocket == 'undefined' ||
    !('__initialize' in WebSocket) || !global.swfobject) {
    return;
  }

  if (global.swfobject.getFlashPlayerVersion().major < 10) {
    return;
  }

  function init () {
    // only start downloading the swf file when
    // we checked that this browser actually supports it
    if (!FlashWS.loaded) {
      if (843 != self.policyPort) {
        var policy = 'xmlsocket://' + self.hostname + ':' + self.policyPort;
        WebSocket.loadFlashPolicyFile(policy);
      }

      WebSocket.__initialize();
      FlashWS.loaded = true;
    }

    fn.call(self);
  }

  var self = this;
  if (document.body) {
    return init();
  }

  util.load(init);
};

/**
 * Feature detection for flashsocket.
 *
 * @return {Boolean} whether this transport is available.
 * @api public
 */

FlashWS.prototype.check = function(){
  if ('undefined' == typeof window) {
    return false;
  }

  if (typeof WebSocket != 'undefined' && !('__initialize' in WebSocket)) {
    return false;
  }

  if (xobject) {
    var control = null;
    try {
      control = new xobject('ShockwaveFlash.ShockwaveFlash');
    } catch (e) { }
    if (control) {
      return true;
    }
  } else {
    for (var i = 0, l = navigator.plugins.length; i < l; i++) {
      for (var j = 0, m = navigator.plugins[i].length; j < m; j++) {
        if (navigator.plugins[i][j].description == 'Shockwave Flash') {
          return true;
        }
      }
    }
  }

  return false;
};

/**
 * Lazy loading of scripts.
 * Based on $script by Dustin Diaz - MIT
 */

var scripts = {};

/**
 * Injects a script. Keeps tracked of injected ones.
 *
 * @param {String} path
 * @param {Function} callback
 * @api private
 */

function create(path, fn){
  if (scripts[path]) return fn();

  var el = document.createElement('script');
  var loaded = false;

  debug('loading "%s"', path);
  el.onload = el.onreadystatechange = function(){
    if (loaded || scripts[path]) return;
    var rs = el.readyState;
    if (!rs || 'loaded' == rs || 'complete' == rs) {
      debug('loaded "%s"', path);
      el.onload = el.onreadystatechange = null;
      loaded = true;
      scripts[path] = true;
      fn();
    }
  };

  el.async = 1;
  el.src = path;

  var head = document.getElementsByTagName('head')[0];
  head.insertBefore(el, head.firstChild);
}

/**
 * Loads scripts and fires a callback.
 *
 * @param {Array} paths
 * @param {Function} callback
 */

function load(arr, fn){
  function process(i){
    if (!arr[i]) return fn();
    create(arr[i], function () {
      process(++i);
    });
  }

  process(0);
}