Initial commit

node_modules/engine.io/lib/engine.io.js

@@ -0,0 +1,126 @@
+/**
+ * Module dependencies.
+ */
+
+var http = require('http');
+
+/**
+ * Invoking the library as a function delegates to attach if the first argument
+ * is an `http.Server`.
+ *
+ * If there are no arguments or the first argument is an options object, then
+ * a new Server instance is returned.
+ *
+ * @param {http.Server} server (if specified, will be attached to by the new Server instance)
+ * @param {Object} options
+ * @return {Server} engine server
+ * @api public
+ */
+
+exports = module.exports = function () {
+  // backwards compatible use as `.attach`
+  // if first argument is an http server
+  if (arguments.length && arguments[0] instanceof http.Server) {
+    return attach.apply(this, arguments);
+  }
+
+  // if first argument is not an http server, then just make a regular eio server
+  return exports.Server.apply(null, arguments);
+};
+
+/**
+ * Protocol revision number.
+ *
+ * @api public
+ */
+
+exports.protocol = 1;
+
+/**
+ * Expose Server constructor.
+ *
+ * @api public
+ */
+
+exports.Server = require('./server');
+
+/**
+ * Expose Socket constructor.
+ *
+ * @api public
+ */
+
+exports.Socket = require('./socket');
+
+/**
+ * Expose Transport constructor.
+ *
+ * @api public
+ */
+
+exports.Transport = require('./transport');
+
+/**
+ * Expose mutable list of available transports.
+ *
+ * @api public
+ */
+
+exports.transports = require('./transports');
+
+/**
+ * Exports parser.
+ *
+ * @api public
+ */
+
+exports.parser = require('engine.io-parser');
+
+/**
+ * Creates an http.Server exclusively used for WS upgrades.
+ *
+ * @param {Number} port
+ * @param {Function} callback
+ * @param {Object} options
+ * @return {Server} websocket.io server
+ * @api public
+ */
+
+exports.listen = listen;
+
+function listen (port, options, fn) {
+  if ('function' === typeof options) {
+    fn = options;
+    options = {};
+  }
+
+  var server = http.createServer(function (req, res) {
+    res.writeHead(501);
+    res.end('Not Implemented');
+  });
+
+  // create engine server
+  var engine = exports.attach(server, options);
+  engine.httpServer = server;
+
+  server.listen(port, fn);
+
+  return engine;
+}
+
+/**
+ * Captures upgrade requests for a http.Server.
+ *
+ * @param {http.Server} server
+ * @param {Object} options
+ * @return {Server} engine server
+ * @api public
+ */
+
+exports.attach = attach;
+
+function attach (server, options) {
+  var engine = new exports.Server(options);
+  engine.attach(server, options);
+  return engine;
+}

node_modules/engine.io/lib/server.js

@@ -0,0 +1,591 @@
+
+/**
+ * Module dependencies.
+ */
+
+var qs = require('querystring');
+var parse = require('url').parse;
+var base64id = require('base64id');
+var transports = require('./transports');
+var EventEmitter = require('events').EventEmitter;
+var Socket = require('./socket');
+var util = require('util');
+var debug = require('debug')('engine');
+var cookieMod = require('cookie');
+
+/**
+ * Module exports.
+ */
+
+module.exports = Server;
+
+/**
+ * Server constructor.
+ *
+ * @param {Object} options
+ * @api public
+ */
+
+function Server (opts) {
+  if (!(this instanceof Server)) {
+    return new Server(opts);
+  }
+
+  this.clients = {};
+  this.clientsCount = 0;
+
+  opts = opts || {};
+
+  this.wsEngine = opts.wsEngine || process.env.EIO_WS_ENGINE || 'ws';
+  this.pingTimeout = opts.pingTimeout || 5000;
+  this.pingInterval = opts.pingInterval || 25000;
+  this.upgradeTimeout = opts.upgradeTimeout || 10000;
+  this.maxHttpBufferSize = opts.maxHttpBufferSize || 10E7;
+  this.transports = opts.transports || Object.keys(transports);
+  this.allowUpgrades = false !== opts.allowUpgrades;
+  this.allowRequest = opts.allowRequest;
+  this.cookie = false !== opts.cookie ? (opts.cookie || 'io') : false;
+  this.cookiePath = false !== opts.cookiePath ? (opts.cookiePath || '/') : false;
+  this.cookieHttpOnly = false !== opts.cookieHttpOnly;
+  this.perMessageDeflate = false !== opts.perMessageDeflate ? (opts.perMessageDeflate || true) : false;
+  this.httpCompression = false !== opts.httpCompression ? (opts.httpCompression || {}) : false;
+  this.initialPacket = opts.initialPacket;
+
+  var self = this;
+
+  // initialize compression options
+  ['perMessageDeflate', 'httpCompression'].forEach(function (type) {
+    var compression = self[type];
+    if (true === compression) self[type] = compression = {};
+    if (compression && null == compression.threshold) {
+      compression.threshold = 1024;
+    }
+  });
+
+  this.init();
+}
+
+/**
+ * Protocol errors mappings.
+ */
+
+Server.errors = {
+  UNKNOWN_TRANSPORT: 0,
+  UNKNOWN_SID: 1,
+  BAD_HANDSHAKE_METHOD: 2,
+  BAD_REQUEST: 3,
+  FORBIDDEN: 4
+};
+
+Server.errorMessages = {
+  0: 'Transport unknown',
+  1: 'Session ID unknown',
+  2: 'Bad handshake method',
+  3: 'Bad request',
+  4: 'Forbidden'
+};
+
+/**
+ * Inherits from EventEmitter.
+ */
+
+util.inherits(Server, EventEmitter);
+
+/**
+ * Initialize websocket server
+ *
+ * @api private
+ */
+
+Server.prototype.init = function () {
+  if (!~this.transports.indexOf('websocket')) return;
+
+  if (this.ws) this.ws.close();
+
+  var wsModule;
+  switch (this.wsEngine) {
+    case 'uws': wsModule = require('uws'); break;
+    case 'ws': wsModule = require('ws'); break;
+    default: throw new Error('unknown wsEngine');
+  }
+  this.ws = new wsModule.Server({
+    noServer: true,
+    clientTracking: false,
+    perMessageDeflate: this.perMessageDeflate,
+    maxPayload: this.maxHttpBufferSize
+  });
+};
+
+/**
+ * Returns a list of available transports for upgrade given a certain transport.
+ *
+ * @return {Array}
+ * @api public
+ */
+
+Server.prototype.upgrades = function (transport) {
+  if (!this.allowUpgrades) return [];
+  return transports[transport].upgradesTo || [];
+};
+
+/**
+ * Verifies a request.
+ *
+ * @param {http.IncomingMessage}
+ * @return {Boolean} whether the request is valid
+ * @api private
+ */
+
+Server.prototype.verify = function (req, upgrade, fn) {
+  // transport check
+  var transport = req._query.transport;
+  if (!~this.transports.indexOf(transport)) {
+    debug('unknown transport "%s"', transport);
+    return fn(Server.errors.UNKNOWN_TRANSPORT, false);
+  }
+
+  // 'Origin' header check
+  var isOriginInvalid = checkInvalidHeaderChar(req.headers.origin);
+  if (isOriginInvalid) {
+    req.headers.origin = null;
+    debug('origin header invalid');
+    return fn(Server.errors.BAD_REQUEST, false);
+  }
+
+  // sid check
+  var sid = req._query.sid;
+  if (sid) {
+    if (!this.clients.hasOwnProperty(sid)) {
+      debug('unknown sid "%s"', sid);
+      return fn(Server.errors.UNKNOWN_SID, false);
+    }
+    if (!upgrade && this.clients[sid].transport.name !== transport) {
+      debug('bad request: unexpected transport without upgrade');
+      return fn(Server.errors.BAD_REQUEST, false);
+    }
+  } else {
+    // handshake is GET only
+    if ('GET' !== req.method) return fn(Server.errors.BAD_HANDSHAKE_METHOD, false);
+    if (!this.allowRequest) return fn(null, true);
+    return this.allowRequest(req, fn);
+  }
+
+  fn(null, true);
+};
+
+/**
+ * Prepares a request by processing the query string.
+ *
+ * @api private
+ */
+
+Server.prototype.prepare = function (req) {
+  // try to leverage pre-existing `req._query` (e.g: from connect)
+  if (!req._query) {
+    req._query = ~req.url.indexOf('?') ? qs.parse(parse(req.url).query) : {};
+  }
+};
+
+/**
+ * Closes all clients.
+ *
+ * @api public
+ */
+
+Server.prototype.close = function () {
+  debug('closing all open clients');
+  for (var i in this.clients) {
+    if (this.clients.hasOwnProperty(i)) {
+      this.clients[i].close(true);
+    }
+  }
+  if (this.ws) {
+    debug('closing webSocketServer');
+    this.ws.close();
+    // don't delete this.ws because it can be used again if the http server starts listening again
+  }
+  return this;
+};
+
+/**
+ * Handles an Engine.IO HTTP request.
+ *
+ * @param {http.IncomingMessage} request
+ * @param {http.ServerResponse|http.OutgoingMessage} response
+ * @api public
+ */
+
+Server.prototype.handleRequest = function (req, res) {
+  debug('handling "%s" http request "%s"', req.method, req.url);
+  this.prepare(req);
+  req.res = res;
+
+  var self = this;
+  this.verify(req, false, function (err, success) {
+    if (!success) {
+      sendErrorMessage(req, res, err);
+      return;
+    }
+
+    if (req._query.sid) {
+      debug('setting new request for existing client');
+      self.clients[req._query.sid].transport.onRequest(req);
+    } else {
+      self.handshake(req._query.transport, req);
+    }
+  });
+};
+
+/**
+ * Sends an Engine.IO Error Message
+ *
+ * @param {http.ServerResponse} response
+ * @param {code} error code
+ * @api private
+ */
+
+function sendErrorMessage (req, res, code) {
+  var headers = { 'Content-Type': 'application/json' };
+
+  var isForbidden = !Server.errorMessages.hasOwnProperty(code);
+  if (isForbidden) {
+    res.writeHead(403, headers);
+    res.end(JSON.stringify({
+      code: Server.errors.FORBIDDEN,
+      message: code || Server.errorMessages[Server.errors.FORBIDDEN]
+    }));
+    return;
+  }
+  if (req.headers.origin) {
+    headers['Access-Control-Allow-Credentials'] = 'true';
+    headers['Access-Control-Allow-Origin'] = req.headers.origin;
+  } else {
+    headers['Access-Control-Allow-Origin'] = '*';
+  }
+  if (res !== undefined) {
+    res.writeHead(400, headers);
+    res.end(JSON.stringify({
+      code: code,
+      message: Server.errorMessages[code]
+    }));
+  }
+}
+
+/**
+ * generate a socket id.
+ * Overwrite this method to generate your custom socket id
+ *
+ * @param {Object} request object
+ * @api public
+ */
+
+Server.prototype.generateId = function (req) {
+  return base64id.generateId();
+};
+
+/**
+ * Handshakes a new client.
+ *
+ * @param {String} transport name
+ * @param {Object} request object
+ * @api private
+ */
+
+Server.prototype.handshake = function (transportName, req) {
+  var id = this.generateId(req);
+
+  debug('handshaking client "%s"', id);
+
+  try {
+    var transport = new transports[transportName](req);
+    if ('polling' === transportName) {
+      transport.maxHttpBufferSize = this.maxHttpBufferSize;
+      transport.httpCompression = this.httpCompression;
+    } else if ('websocket' === transportName) {
+      transport.perMessageDeflate = this.perMessageDeflate;
+    }
+
+    if (req._query && req._query.b64) {
+      transport.supportsBinary = false;
+    } else {
+      transport.supportsBinary = true;
+    }
+  } catch (e) {
+    debug('error handshaking to transport "%s"', transportName);
+    sendErrorMessage(req, req.res, Server.errors.BAD_REQUEST);
+    return;
+  }
+  var socket = new Socket(id, this, transport, req);
+  var self = this;
+
+  if (false !== this.cookie) {
+    transport.on('headers', function (headers) {
+      headers['Set-Cookie'] = cookieMod.serialize(self.cookie, id,
+        {
+          path: self.cookiePath,
+          httpOnly: self.cookiePath ? self.cookieHttpOnly : false,
+          sameSite: true
+        });
+    });
+  }
+
+  transport.onRequest(req);
+
+  this.clients[id] = socket;
+  this.clientsCount++;
+
+  socket.once('close', function () {
+    delete self.clients[id];
+    self.clientsCount--;
+  });
+
+  this.emit('connection', socket);
+};
+
+/**
+ * Handles an Engine.IO HTTP Upgrade.
+ *
+ * @api public
+ */
+
+Server.prototype.handleUpgrade = function (req, socket, upgradeHead) {
+  this.prepare(req);
+
+  var self = this;
+  this.verify(req, true, function (err, success) {
+    if (!success) {
+      abortConnection(socket, err);
+      return;
+    }
+
+    var head = Buffer.from(upgradeHead); // eslint-disable-line node/no-deprecated-api
+    upgradeHead = null;
+
+    // delegate to ws
+    self.ws.handleUpgrade(req, socket, head, function (conn) {
+      self.onWebSocket(req, conn);
+    });
+  });
+};
+
+/**
+ * Called upon a ws.io connection.
+ *
+ * @param {ws.Socket} websocket
+ * @api private
+ */
+
+Server.prototype.onWebSocket = function (req, socket) {
+  socket.on('error', onUpgradeError);
+
+  if (transports[req._query.transport] !== undefined && !transports[req._query.transport].prototype.handlesUpgrades) {
+    debug('transport doesnt handle upgraded requests');
+    socket.close();
+    return;
+  }
+
+  // get client id
+  var id = req._query.sid;
+
+  // keep a reference to the ws.Socket
+  req.websocket = socket;
+
+  if (id) {
+    var client = this.clients[id];
+    if (!client) {
+      debug('upgrade attempt for closed client');
+      socket.close();
+    } else if (client.upgrading) {
+      debug('transport has already been trying to upgrade');
+      socket.close();
+    } else if (client.upgraded) {
+      debug('transport had already been upgraded');
+      socket.close();
+    } else {
+      debug('upgrading existing transport');
+
+      // transport error handling takes over
+      socket.removeListener('error', onUpgradeError);
+
+      var transport = new transports[req._query.transport](req);
+      if (req._query && req._query.b64) {
+        transport.supportsBinary = false;
+      } else {
+        transport.supportsBinary = true;
+      }
+      transport.perMessageDeflate = this.perMessageDeflate;
+      client.maybeUpgrade(transport);
+    }
+  } else {
+    // transport error handling takes over
+    socket.removeListener('error', onUpgradeError);
+
+    this.handshake(req._query.transport, req);
+  }
+
+  function onUpgradeError () {
+    debug('websocket error before upgrade');
+    // socket.close() not needed
+  }
+};
+
+/**
+ * Captures upgrade requests for a http.Server.
+ *
+ * @param {http.Server} server
+ * @param {Object} options
+ * @api public
+ */
+
+Server.prototype.attach = function (server, options) {
+  var self = this;
+  options = options || {};
+  var path = (options.path || '/engine.io').replace(/\/$/, '');
+
+  var destroyUpgradeTimeout = options.destroyUpgradeTimeout || 1000;
+
+  // normalize path
+  path += '/';
+
+  function check (req) {
+    if ('OPTIONS' === req.method && false === options.handlePreflightRequest) {
+      return false;
+    }
+    return path === req.url.substr(0, path.length);
+  }
+
+  // cache and clean up listeners
+  var listeners = server.listeners('request').slice(0);
+  server.removeAllListeners('request');
+  server.on('close', self.close.bind(self));
+  server.on('listening', self.init.bind(self));
+
+  // add request handler
+  server.on('request', function (req, res) {
+    if (check(req)) {
+      debug('intercepting request for path "%s"', path);
+      if ('OPTIONS' === req.method && 'function' === typeof options.handlePreflightRequest) {
+        options.handlePreflightRequest.call(server, req, res);
+      } else {
+        self.handleRequest(req, res);
+      }
+    } else {
+      for (var i = 0, l = listeners.length; i < l; i++) {
+        listeners[i].call(server, req, res);
+      }
+    }
+  });
+
+  if (~self.transports.indexOf('websocket')) {
+    server.on('upgrade', function (req, socket, head) {
+      if (check(req)) {
+        self.handleUpgrade(req, socket, head);
+      } else if (false !== options.destroyUpgrade) {
+        // default node behavior is to disconnect when no handlers
+        // but by adding a handler, we prevent that
+        // and if no eio thing handles the upgrade
+        // then the socket needs to die!
+        setTimeout(function () {
+          if (socket.writable && socket.bytesWritten <= 0) {
+            return socket.end();
+          }
+        }, destroyUpgradeTimeout);
+      }
+    });
+  }
+};
+
+/**
+ * Closes the connection
+ *
+ * @param {net.Socket} socket
+ * @param {code} error code
+ * @api private
+ */
+
+function abortConnection (socket, code) {
+  socket.on('error', () => {
+    debug('ignoring error from closed connection');
+  });
+  if (socket.writable) {
+    var message = Server.errorMessages.hasOwnProperty(code) ? Server.errorMessages[code] : String(code || '');
+    var length = Buffer.byteLength(message);
+    socket.write(
+      'HTTP/1.1 400 Bad Request\r\n' +
+      'Connection: close\r\n' +
+      'Content-type: text/html\r\n' +
+      'Content-Length: ' + length + '\r\n' +
+      '\r\n' +
+      message
+    );
+  }
+  socket.destroy();
+}
+
+/* eslint-disable */
+
+/**
+ * From https://github.com/nodejs/node/blob/v8.4.0/lib/_http_common.js#L303-L354
+ *
+ * True if val contains an invalid field-vchar
+ *  field-value    = *( field-content / obs-fold )
+ *  field-content  = field-vchar [ 1*( SP / HTAB ) field-vchar ]
+ *  field-vchar    = VCHAR / obs-text
+ *
+ * checkInvalidHeaderChar() is currently designed to be inlinable by v8,
+ * so take care when making changes to the implementation so that the source
+ * code size does not exceed v8's default max_inlined_source_size setting.
+ **/
+var validHdrChars = [
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, // 0 - 15
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 16 - 31
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 32 - 47
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 48 - 63
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 64 - 79
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 80 - 95
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 96 - 111
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, // 112 - 127
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 128 ...
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1  // ... 255
+];
+
+function checkInvalidHeaderChar(val) {
+  val += '';
+  if (val.length < 1)
+    return false;
+  if (!validHdrChars[val.charCodeAt(0)]) {
+    debug('invalid header, index 0, char "%s"', val.charCodeAt(0));
+    return true;
+  }
+  if (val.length < 2)
+    return false;
+  if (!validHdrChars[val.charCodeAt(1)]) {
+    debug('invalid header, index 1, char "%s"', val.charCodeAt(1));
+    return true;
+  }
+  if (val.length < 3)
+    return false;
+  if (!validHdrChars[val.charCodeAt(2)]) {
+    debug('invalid header, index 2, char "%s"', val.charCodeAt(2));
+    return true;
+  }
+  if (val.length < 4)
+    return false;
+  if (!validHdrChars[val.charCodeAt(3)]) {
+    debug('invalid header, index 3, char "%s"', val.charCodeAt(3));
+    return true;
+  }
+  for (var i = 4; i < val.length; ++i) {
+    if (!validHdrChars[val.charCodeAt(i)]) {
+      debug('invalid header, index "%i", char "%s"', i, val.charCodeAt(i));
+      return true;
+    }
+  }
+  return false;
+}

node_modules/engine.io/lib/socket.js

@@ -0,0 +1,486 @@
+/**
+ * Module dependencies.
+ */
+
+var EventEmitter = require('events').EventEmitter;
+var util = require('util');
+var debug = require('debug')('engine:socket');
+
+/**
+ * Module exports.
+ */
+
+module.exports = Socket;
+
+/**
+ * Client class (abstract).
+ *
+ * @api private
+ */
+
+function Socket (id, server, transport, req) {
+  this.id = id;
+  this.server = server;
+  this.upgrading = false;
+  this.upgraded = false;
+  this.readyState = 'opening';
+  this.writeBuffer = [];
+  this.packetsFn = [];
+  this.sentCallbackFn = [];
+  this.cleanupFn = [];
+  this.request = req;
+
+  // Cache IP since it might not be in the req later
+  if (req.websocket && req.websocket._socket) {
+    this.remoteAddress = req.websocket._socket.remoteAddress;
+  } else {
+    this.remoteAddress = req.connection.remoteAddress;
+  }
+
+  this.checkIntervalTimer = null;
+  this.upgradeTimeoutTimer = null;
+  this.pingTimeoutTimer = null;
+
+  this.setTransport(transport);
+  this.onOpen();
+}
+
+/**
+ * Inherits from EventEmitter.
+ */
+
+util.inherits(Socket, EventEmitter);
+
+/**
+ * Called upon transport considered open.
+ *
+ * @api private
+ */
+
+Socket.prototype.onOpen = function () {
+  this.readyState = 'open';
+
+  // sends an `open` packet
+  this.transport.sid = this.id;
+  this.sendPacket('open', JSON.stringify({
+    sid: this.id,
+    upgrades: this.getAvailableUpgrades(),
+    pingInterval: this.server.pingInterval,
+    pingTimeout: this.server.pingTimeout
+  }));
+
+  if (this.server.initialPacket) {
+    this.sendPacket('message', this.server.initialPacket);
+  }
+
+  this.emit('open');
+  this.setPingTimeout();
+};
+
+/**
+ * Called upon transport packet.
+ *
+ * @param {Object} packet
+ * @api private
+ */
+
+Socket.prototype.onPacket = function (packet) {
+  if ('open' === this.readyState) {
+    // export packet event
+    debug('packet');
+    this.emit('packet', packet);
+
+    // Reset ping timeout on any packet, incoming data is a good sign of
+    // other side's liveness
+    this.setPingTimeout();
+
+    switch (packet.type) {
+      case 'ping':
+        debug('got ping');
+        this.sendPacket('pong');
+        this.emit('heartbeat');
+        break;
+
+      case 'error':
+        this.onClose('parse error');
+        break;
+
+      case 'message':
+        this.emit('data', packet.data);
+        this.emit('message', packet.data);
+        break;
+    }
+  } else {
+    debug('packet received with closed socket');
+  }
+};
+
+/**
+ * Called upon transport error.
+ *
+ * @param {Error} error object
+ * @api private
+ */
+
+Socket.prototype.onError = function (err) {
+  debug('transport error');
+  this.onClose('transport error', err);
+};
+
+/**
+ * Sets and resets ping timeout timer based on client pings.
+ *
+ * @api private
+ */
+
+Socket.prototype.setPingTimeout = function () {
+  var self = this;
+  clearTimeout(self.pingTimeoutTimer);
+  self.pingTimeoutTimer = setTimeout(function () {
+    self.onClose('ping timeout');
+  }, self.server.pingInterval + self.server.pingTimeout);
+};
+
+/**
+ * Attaches handlers for the given transport.
+ *
+ * @param {Transport} transport
+ * @api private
+ */
+
+Socket.prototype.setTransport = function (transport) {
+  var onError = this.onError.bind(this);
+  var onPacket = this.onPacket.bind(this);
+  var flush = this.flush.bind(this);
+  var onClose = this.onClose.bind(this, 'transport close');
+
+  this.transport = transport;
+  this.transport.once('error', onError);
+  this.transport.on('packet', onPacket);
+  this.transport.on('drain', flush);
+  this.transport.once('close', onClose);
+  // this function will manage packet events (also message callbacks)
+  this.setupSendCallback();
+
+  this.cleanupFn.push(function () {
+    transport.removeListener('error', onError);
+    transport.removeListener('packet', onPacket);
+    transport.removeListener('drain', flush);
+    transport.removeListener('close', onClose);
+  });
+};
+
+/**
+ * Upgrades socket to the given transport
+ *
+ * @param {Transport} transport
+ * @api private
+ */
+
+Socket.prototype.maybeUpgrade = function (transport) {
+  debug('might upgrade socket transport from "%s" to "%s"'
+    , this.transport.name, transport.name);
+
+  this.upgrading = true;
+
+  var self = this;
+
+  // set transport upgrade timer
+  self.upgradeTimeoutTimer = setTimeout(function () {
+    debug('client did not complete upgrade - closing transport');
+    cleanup();
+    if ('open' === transport.readyState) {
+      transport.close();
+    }
+  }, this.server.upgradeTimeout);
+
+  function onPacket (packet) {
+    if ('ping' === packet.type && 'probe' === packet.data) {
+      transport.send([{ type: 'pong', data: 'probe' }]);
+      self.emit('upgrading', transport);
+      clearInterval(self.checkIntervalTimer);
+      self.checkIntervalTimer = setInterval(check, 100);
+    } else if ('upgrade' === packet.type && self.readyState !== 'closed') {
+      debug('got upgrade packet - upgrading');
+      cleanup();
+      self.transport.discard();
+      self.upgraded = true;
+      self.clearTransport();
+      self.setTransport(transport);
+      self.emit('upgrade', transport);
+      self.setPingTimeout();
+      self.flush();
+      if (self.readyState === 'closing') {
+        transport.close(function () {
+          self.onClose('forced close');
+        });
+      }
+    } else {
+      cleanup();
+      transport.close();
+    }
+  }
+
+  // we force a polling cycle to ensure a fast upgrade
+  function check () {
+    if ('polling' === self.transport.name && self.transport.writable) {
+      debug('writing a noop packet to polling for fast upgrade');
+      self.transport.send([{ type: 'noop' }]);
+    }
+  }
+
+  function cleanup () {
+    self.upgrading = false;
+
+    clearInterval(self.checkIntervalTimer);
+    self.checkIntervalTimer = null;
+
+    clearTimeout(self.upgradeTimeoutTimer);
+    self.upgradeTimeoutTimer = null;
+
+    transport.removeListener('packet', onPacket);
+    transport.removeListener('close', onTransportClose);
+    transport.removeListener('error', onError);
+    self.removeListener('close', onClose);
+  }
+
+  function onError (err) {
+    debug('client did not complete upgrade - %s', err);
+    cleanup();
+    transport.close();
+    transport = null;
+  }
+
+  function onTransportClose () {
+    onError('transport closed');
+  }
+
+  function onClose () {
+    onError('socket closed');
+  }
+
+  transport.on('packet', onPacket);
+  transport.once('close', onTransportClose);
+  transport.once('error', onError);
+
+  self.once('close', onClose);
+};
+
+/**
+ * Clears listeners and timers associated with current transport.
+ *
+ * @api private
+ */
+
+Socket.prototype.clearTransport = function () {
+  var cleanup;
+
+  var toCleanUp = this.cleanupFn.length;
+
+  for (var i = 0; i < toCleanUp; i++) {
+    cleanup = this.cleanupFn.shift();
+    cleanup();
+  }
+
+  // silence further transport errors and prevent uncaught exceptions
+  this.transport.on('error', function () {
+    debug('error triggered by discarded transport');
+  });
+
+  // ensure transport won't stay open
+  this.transport.close();
+
+  clearTimeout(this.pingTimeoutTimer);
+};
+
+/**
+ * Called upon transport considered closed.
+ * Possible reasons: `ping timeout`, `client error`, `parse error`,
+ * `transport error`, `server close`, `transport close`
+ */
+
+Socket.prototype.onClose = function (reason, description) {
+  if ('closed' !== this.readyState) {
+    this.readyState = 'closed';
+    clearTimeout(this.pingTimeoutTimer);
+    clearInterval(this.checkIntervalTimer);
+    this.checkIntervalTimer = null;
+    clearTimeout(this.upgradeTimeoutTimer);
+    var self = this;
+    // clean writeBuffer in next tick, so developers can still
+    // grab the writeBuffer on 'close' event
+    process.nextTick(function () {
+      self.writeBuffer = [];
+    });
+    this.packetsFn = [];
+    this.sentCallbackFn = [];
+    this.clearTransport();
+    this.emit('close', reason, description);
+  }
+};
+
+/**
+ * Setup and manage send callback
+ *
+ * @api private
+ */
+
+Socket.prototype.setupSendCallback = function () {
+  var self = this;
+  this.transport.on('drain', onDrain);
+
+  this.cleanupFn.push(function () {
+    self.transport.removeListener('drain', onDrain);
+  });
+
+  // the message was sent successfully, execute the callback
+  function onDrain () {
+    if (self.sentCallbackFn.length > 0) {
+      var seqFn = self.sentCallbackFn.splice(0, 1)[0];
+      if ('function' === typeof seqFn) {
+        debug('executing send callback');
+        seqFn(self.transport);
+      } else if (Array.isArray(seqFn)) {
+        debug('executing batch send callback');
+        for (var l = seqFn.length, i = 0; i < l; i++) {
+          if ('function' === typeof seqFn[i]) {
+            seqFn[i](self.transport);
+          }
+        }
+      }
+    }
+  }
+};
+
+/**
+ * Sends a message packet.
+ *
+ * @param {String} message
+ * @param {Object} options
+ * @param {Function} callback
+ * @return {Socket} for chaining
+ * @api public
+ */
+
+Socket.prototype.send =
+Socket.prototype.write = function (data, options, callback) {
+  this.sendPacket('message', data, options, callback);
+  return this;
+};
+
+/**
+ * Sends a packet.
+ *
+ * @param {String} packet type
+ * @param {String} optional, data
+ * @param {Object} options
+ * @api private
+ */
+
+Socket.prototype.sendPacket = function (type, data, options, callback) {
+  if ('function' === typeof options) {
+    callback = options;
+    options = null;
+  }
+
+  options = options || {};
+  options.compress = false !== options.compress;
+
+  if ('closing' !== this.readyState && 'closed' !== this.readyState) {
+    debug('sending packet "%s" (%s)', type, data);
+
+    var packet = {
+      type: type,
+      options: options
+    };
+    if (data) packet.data = data;
+
+    // exports packetCreate event
+    this.emit('packetCreate', packet);
+
+    this.writeBuffer.push(packet);
+
+    // add send callback to object, if defined
+    if (callback) this.packetsFn.push(callback);
+
+    this.flush();
+  }
+};
+
+/**
+ * Attempts to flush the packets buffer.
+ *
+ * @api private
+ */
+
+Socket.prototype.flush = function () {
+  if ('closed' !== this.readyState &&
+                this.transport.writable &&
+                this.writeBuffer.length) {
+    debug('flushing buffer to transport');
+    this.emit('flush', this.writeBuffer);
+    this.server.emit('flush', this, this.writeBuffer);
+    var wbuf = this.writeBuffer;
+    this.writeBuffer = [];
+    if (!this.transport.supportsFraming) {
+      this.sentCallbackFn.push(this.packetsFn);
+    } else {
+      this.sentCallbackFn.push.apply(this.sentCallbackFn, this.packetsFn);
+    }
+    this.packetsFn = [];
+    this.transport.send(wbuf);
+    this.emit('drain');
+    this.server.emit('drain', this);
+  }
+};
+
+/**
+ * Get available upgrades for this socket.
+ *
+ * @api private
+ */
+
+Socket.prototype.getAvailableUpgrades = function () {
+  var availableUpgrades = [];
+  var allUpgrades = this.server.upgrades(this.transport.name);
+  for (var i = 0, l = allUpgrades.length; i < l; ++i) {
+    var upg = allUpgrades[i];
+    if (this.server.transports.indexOf(upg) !== -1) {
+      availableUpgrades.push(upg);
+    }
+  }
+  return availableUpgrades;
+};
+
+/**
+ * Closes the socket and underlying transport.
+ *
+ * @param {Boolean} optional, discard
+ * @return {Socket} for chaining
+ * @api public
+ */
+
+Socket.prototype.close = function (discard) {
+  if ('open' !== this.readyState) return;
+
+  this.readyState = 'closing';
+
+  if (this.writeBuffer.length) {
+    this.once('drain', this.closeTransport.bind(this, discard));
+    return;
+  }
+
+  this.closeTransport(discard);
+};
+
+/**
+ * Closes the underlying transport.
+ *
+ * @param {Boolean} discard
+ * @api private
+ */
+
+Socket.prototype.closeTransport = function (discard) {
+  if (discard) this.transport.discard();
+  this.transport.close(this.onClose.bind(this, 'forced close'));
+};

node_modules/engine.io/lib/transport.js

@@ -0,0 +1,128 @@
+
+/**
+ * Module dependencies.
+ */
+
+var EventEmitter = require('events').EventEmitter;
+var parser = require('engine.io-parser');
+var util = require('util');
+var debug = require('debug')('engine:transport');
+
+/**
+ * Expose the constructor.
+ */
+
+module.exports = Transport;
+
+/**
+ * Noop function.
+ *
+ * @api private
+ */
+
+function noop () {}
+
+/**
+ * Transport constructor.
+ *
+ * @param {http.IncomingMessage} request
+ * @api public
+ */
+
+function Transport (req) {
+  this.readyState = 'open';
+  this.discarded = false;
+}
+
+/**
+ * Inherits from EventEmitter.
+ */
+
+util.inherits(Transport, EventEmitter);
+
+/**
+ * Flags the transport as discarded.
+ *
+ * @api private
+ */
+
+Transport.prototype.discard = function () {
+  this.discarded = true;
+};
+
+/**
+ * Called with an incoming HTTP request.
+ *
+ * @param {http.IncomingMessage} request
+ * @api private
+ */
+
+Transport.prototype.onRequest = function (req) {
+  debug('setting request');
+  this.req = req;
+};
+
+/**
+ * Closes the transport.
+ *
+ * @api private
+ */
+
+Transport.prototype.close = function (fn) {
+  if ('closed' === this.readyState || 'closing' === this.readyState) return;
+
+  this.readyState = 'closing';
+  this.doClose(fn || noop);
+};
+
+/**
+ * Called with a transport error.
+ *
+ * @param {String} message error
+ * @param {Object} error description
+ * @api private
+ */
+
+Transport.prototype.onError = function (msg, desc) {
+  if (this.listeners('error').length) {
+    var err = new Error(msg);
+    err.type = 'TransportError';
+    err.description = desc;
+    this.emit('error', err);
+  } else {
+    debug('ignored transport error %s (%s)', msg, desc);
+  }
+};
+
+/**
+ * Called with parsed out a packets from the data stream.
+ *
+ * @param {Object} packet
+ * @api private
+ */
+
+Transport.prototype.onPacket = function (packet) {
+  this.emit('packet', packet);
+};
+
+/**
+ * Called with the encoded packet data.
+ *
+ * @param {String} data
+ * @api private
+ */
+
+Transport.prototype.onData = function (data) {
+  this.onPacket(parser.decodePacket(data));
+};
+
+/**
+ * Called upon transport close.
+ *
+ * @api private
+ */
+
+Transport.prototype.onClose = function () {
+  this.readyState = 'closed';
+  this.emit('close');
+};

node_modules/engine.io/lib/transports/index.js

@@ -0,0 +1,36 @@
+
+/**
+ * Module dependencies.
+ */
+
+var XHR = require('./polling-xhr');
+var JSONP = require('./polling-jsonp');
+
+/**
+ * Export transports.
+ */
+
+module.exports = exports = {
+  polling: polling,
+  websocket: require('./websocket')
+};
+
+/**
+ * Export upgrades map.
+ */
+
+exports.polling.upgradesTo = ['websocket'];
+
+/**
+ * Polling polymorphic constructor.
+ *
+ * @api private
+ */
+
+function polling (req) {
+  if ('string' === typeof req._query.j) {
+    return new JSONP(req);
+  } else {
+    return new XHR(req);
+  }
+}

node_modules/engine.io/lib/transports/polling-jsonp.js

@@ -0,0 +1,75 @@
+
+/**
+ * Module dependencies.
+ */
+
+var Polling = require('./polling');
+var qs = require('querystring');
+var rDoubleSlashes = /\\\\n/g;
+var rSlashes = /(\\)?\\n/g;
+var util = require('util');
+
+/**
+ * Module exports.
+ */
+
+module.exports = JSONP;
+
+/**
+ * JSON-P polling transport.
+ *
+ * @api public
+ */
+
+function JSONP (req) {
+  Polling.call(this, req);
+
+  this.head = '___eio[' + (req._query.j || '').replace(/[^0-9]/g, '') + '](';
+  this.foot = ');';
+}
+
+/**
+ * Inherits from Polling.
+ */
+
+util.inherits(JSONP, Polling);
+
+/**
+ * Handles incoming data.
+ * Due to a bug in \n handling by browsers, we expect a escaped string.
+ *
+ * @api private
+ */
+
+JSONP.prototype.onData = function (data) {
+  // we leverage the qs module so that we get built-in DoS protection
+  // and the fast alternative to decodeURIComponent
+  data = qs.parse(data).d;
+  if ('string' === typeof data) {
+    // client will send already escaped newlines as \\\\n and newlines as \\n
+    // \\n must be replaced with \n and \\\\n with \\n
+    data = data.replace(rSlashes, function (match, slashes) {
+      return slashes ? match : '\n';
+    });
+    Polling.prototype.onData.call(this, data.replace(rDoubleSlashes, '\\n'));
+  }
+};
+
+/**
+ * Performs the write.
+ *
+ * @api private
+ */
+
+JSONP.prototype.doWrite = function (data, options, callback) {
+  // we must output valid javascript, not valid json
+  // see: http://timelessrepo.com/json-isnt-a-javascript-subset
+  var js = JSON.stringify(data)
+    .replace(/\u2028/g, '\\u2028')
+    .replace(/\u2029/g, '\\u2029');
+
+  // prepare response
+  data = this.head + js + this.foot;
+
+  Polling.prototype.doWrite.call(this, data, options, callback);
+};

node_modules/engine.io/lib/transports/polling-xhr.js

@@ -0,0 +1,69 @@
+
+/**
+ * Module dependencies.
+ */
+
+var Polling = require('./polling');
+var util = require('util');
+
+/**
+ * Module exports.
+ */
+
+module.exports = XHR;
+
+/**
+ * Ajax polling transport.
+ *
+ * @api public
+ */
+
+function XHR (req) {
+  Polling.call(this, req);
+}
+
+/**
+ * Inherits from Polling.
+ */
+
+util.inherits(XHR, Polling);
+
+/**
+ * Overrides `onRequest` to handle `OPTIONS`..
+ *
+ * @param {http.IncomingMessage}
+ * @api private
+ */
+
+XHR.prototype.onRequest = function (req) {
+  if ('OPTIONS' === req.method) {
+    var res = req.res;
+    var headers = this.headers(req);
+    headers['Access-Control-Allow-Headers'] = 'Content-Type';
+    res.writeHead(200, headers);
+    res.end();
+  } else {
+    Polling.prototype.onRequest.call(this, req);
+  }
+};
+
+/**
+ * Returns headers for a response.
+ *
+ * @param {http.IncomingMessage} request
+ * @param {Object} extra headers
+ * @api private
+ */
+
+XHR.prototype.headers = function (req, headers) {
+  headers = headers || {};
+
+  if (req.headers.origin) {
+    headers['Access-Control-Allow-Credentials'] = 'true';
+    headers['Access-Control-Allow-Origin'] = req.headers.origin;
+  } else {
+    headers['Access-Control-Allow-Origin'] = '*';
+  }
+
+  return Polling.prototype.headers.call(this, req, headers);
+};

node_modules/engine.io/lib/transports/polling.js

@@ -0,0 +1,407 @@
+
+/**
+ * Module requirements.
+ */
+
+var Transport = require('../transport');
+var parser = require('engine.io-parser');
+var zlib = require('zlib');
+var accepts = require('accepts');
+var util = require('util');
+var debug = require('debug')('engine:polling');
+
+var compressionMethods = {
+  gzip: zlib.createGzip,
+  deflate: zlib.createDeflate
+};
+
+/**
+ * Exports the constructor.
+ */
+
+module.exports = Polling;
+
+/**
+ * HTTP polling constructor.
+ *
+ * @api public.
+ */
+
+function Polling (req) {
+  Transport.call(this, req);
+
+  this.closeTimeout = 30 * 1000;
+  this.maxHttpBufferSize = null;
+  this.httpCompression = null;
+}
+
+/**
+ * Inherits from Transport.
+ *
+ * @api public.
+ */
+
+util.inherits(Polling, Transport);
+
+/**
+ * Transport name
+ *
+ * @api public
+ */
+
+Polling.prototype.name = 'polling';
+
+/**
+ * Overrides onRequest.
+ *
+ * @param {http.IncomingMessage}
+ * @api private
+ */
+
+Polling.prototype.onRequest = function (req) {
+  var res = req.res;
+
+  if ('GET' === req.method) {
+    this.onPollRequest(req, res);
+  } else if ('POST' === req.method) {
+    this.onDataRequest(req, res);
+  } else {
+    res.writeHead(500);
+    res.end();
+  }
+};
+
+/**
+ * The client sends a request awaiting for us to send data.
+ *
+ * @api private
+ */
+
+Polling.prototype.onPollRequest = function (req, res) {
+  if (this.req) {
+    debug('request overlap');
+    // assert: this.res, '.req and .res should be (un)set together'
+    this.onError('overlap from client');
+    res.writeHead(500);
+    res.end();
+    return;
+  }
+
+  debug('setting request');
+
+  this.req = req;
+  this.res = res;
+
+  var self = this;
+
+  function onClose () {
+    self.onError('poll connection closed prematurely');
+  }
+
+  function cleanup () {
+    req.removeListener('close', onClose);
+    self.req = self.res = null;
+  }
+
+  req.cleanup = cleanup;
+  req.on('close', onClose);
+
+  this.writable = true;
+  this.emit('drain');
+
+  // if we're still writable but had a pending close, trigger an empty send
+  if (this.writable && this.shouldClose) {
+    debug('triggering empty send to append close packet');
+    this.send([{ type: 'noop' }]);
+  }
+};
+
+/**
+ * The client sends a request with data.
+ *
+ * @api private
+ */
+
+Polling.prototype.onDataRequest = function (req, res) {
+  if (this.dataReq) {
+    // assert: this.dataRes, '.dataReq and .dataRes should be (un)set together'
+    this.onError('data request overlap from client');
+    res.writeHead(500);
+    res.end();
+    return;
+  }
+
+  var isBinary = 'application/octet-stream' === req.headers['content-type'];
+
+  this.dataReq = req;
+  this.dataRes = res;
+
+  var chunks = isBinary ? Buffer.concat([]) : '';
+  var self = this;
+
+  function cleanup () {
+    req.removeListener('data', onData);
+    req.removeListener('end', onEnd);
+    req.removeListener('close', onClose);
+    self.dataReq = self.dataRes = chunks = null;
+  }
+
+  function onClose () {
+    cleanup();
+    self.onError('data request connection closed prematurely');
+  }
+
+  function onData (data) {
+    var contentLength;
+    if (isBinary) {
+      chunks = Buffer.concat([chunks, data]);
+      contentLength = chunks.length;
+    } else {
+      chunks += data;
+      contentLength = Buffer.byteLength(chunks);
+    }
+
+    if (contentLength > self.maxHttpBufferSize) {
+      chunks = isBinary ? Buffer.concat([]) : '';
+      req.connection.destroy();
+    }
+  }
+
+  function onEnd () {
+    self.onData(chunks);
+
+    var headers = {
+      // text/html is required instead of text/plain to avoid an
+      // unwanted download dialog on certain user-agents (GH-43)
+      'Content-Type': 'text/html',
+      'Content-Length': 2
+    };
+
+    res.writeHead(200, self.headers(req, headers));
+    res.end('ok');
+    cleanup();
+  }
+
+  req.on('close', onClose);
+  if (!isBinary) req.setEncoding('utf8');
+  req.on('data', onData);
+  req.on('end', onEnd);
+};
+
+/**
+ * Processes the incoming data payload.
+ *
+ * @param {String} encoded payload
+ * @api private
+ */
+
+Polling.prototype.onData = function (data) {
+  debug('received "%s"', data);
+  var self = this;
+  var callback = function (packet) {
+    if ('close' === packet.type) {
+      debug('got xhr close packet');
+      self.onClose();
+      return false;
+    }
+
+    self.onPacket(packet);
+  };
+
+  parser.decodePayload(data, callback);
+};
+
+/**
+ * Overrides onClose.
+ *
+ * @api private
+ */
+
+Polling.prototype.onClose = function () {
+  if (this.writable) {
+    // close pending poll request
+    this.send([{ type: 'noop' }]);
+  }
+  Transport.prototype.onClose.call(this);
+};
+
+/**
+ * Writes a packet payload.
+ *
+ * @param {Object} packet
+ * @api private
+ */
+
+Polling.prototype.send = function (packets) {
+  this.writable = false;
+
+  if (this.shouldClose) {
+    debug('appending close packet to payload');
+    packets.push({ type: 'close' });
+    this.shouldClose();
+    this.shouldClose = null;
+  }
+
+  var self = this;
+  parser.encodePayload(packets, this.supportsBinary, function (data) {
+    var compress = packets.some(function (packet) {
+      return packet.options && packet.options.compress;
+    });
+    self.write(data, { compress: compress });
+  });
+};
+
+/**
+ * Writes data as response to poll request.
+ *
+ * @param {String} data
+ * @param {Object} options
+ * @api private
+ */
+
+Polling.prototype.write = function (data, options) {
+  debug('writing "%s"', data);
+  var self = this;
+  this.doWrite(data, options, function () {
+    self.req.cleanup();
+  });
+};
+
+/**
+ * Performs the write.
+ *
+ * @api private
+ */
+
+Polling.prototype.doWrite = function (data, options, callback) {
+  var self = this;
+
+  // explicit UTF-8 is required for pages not served under utf
+  var isString = typeof data === 'string';
+  var contentType = isString
+    ? 'text/plain; charset=UTF-8'
+    : 'application/octet-stream';
+
+  var headers = {
+    'Content-Type': contentType
+  };
+
+  if (!this.httpCompression || !options.compress) {
+    respond(data);
+    return;
+  }
+
+  var len = isString ? Buffer.byteLength(data) : data.length;
+  if (len < this.httpCompression.threshold) {
+    respond(data);
+    return;
+  }
+
+  var encoding = accepts(this.req).encodings(['gzip', 'deflate']);
+  if (!encoding) {
+    respond(data);
+    return;
+  }
+
+  this.compress(data, encoding, function (err, data) {
+    if (err) {
+      self.res.writeHead(500);
+      self.res.end();
+      callback(err);
+      return;
+    }
+
+    headers['Content-Encoding'] = encoding;
+    respond(data);
+  });
+
+  function respond (data) {
+    headers['Content-Length'] = 'string' === typeof data ? Buffer.byteLength(data) : data.length;
+    self.res.writeHead(200, self.headers(self.req, headers));
+    self.res.end(data);
+    callback();
+  }
+};
+
+/**
+ * Compresses data.
+ *
+ * @api private
+ */
+
+Polling.prototype.compress = function (data, encoding, callback) {
+  debug('compressing');
+
+  var buffers = [];
+  var nread = 0;
+
+  compressionMethods[encoding](this.httpCompression)
+    .on('error', callback)
+    .on('data', function (chunk) {
+      buffers.push(chunk);
+      nread += chunk.length;
+    })
+    .on('end', function () {
+      callback(null, Buffer.concat(buffers, nread));
+    })
+    .end(data);
+};
+
+/**
+ * Closes the transport.
+ *
+ * @api private
+ */
+
+Polling.prototype.doClose = function (fn) {
+  debug('closing');
+
+  var self = this;
+  var closeTimeoutTimer;
+
+  if (this.dataReq) {
+    debug('aborting ongoing data request');
+    this.dataReq.destroy();
+  }
+
+  if (this.writable) {
+    debug('transport writable - closing right away');
+    this.send([{ type: 'close' }]);
+    onClose();
+  } else if (this.discarded) {
+    debug('transport discarded - closing right away');
+    onClose();
+  } else {
+    debug('transport not writable - buffering orderly close');
+    this.shouldClose = onClose;
+    closeTimeoutTimer = setTimeout(onClose, this.closeTimeout);
+  }
+
+  function onClose () {
+    clearTimeout(closeTimeoutTimer);
+    fn();
+    self.onClose();
+  }
+};
+
+/**
+ * Returns headers for a response.
+ *
+ * @param {http.IncomingMessage} request
+ * @param {Object} extra headers
+ * @api private
+ */
+
+Polling.prototype.headers = function (req, headers) {
+  headers = headers || {};
+
+  // prevent XSS warnings on IE
+  // https://github.com/LearnBoost/socket.io/pull/1333
+  var ua = req.headers['user-agent'];
+  if (ua && (~ua.indexOf(';MSIE') || ~ua.indexOf('Trident/'))) {
+    headers['X-XSS-Protection'] = '0';
+  }
+
+  this.emit('headers', headers);
+  return headers;
+};

node_modules/engine.io/lib/transports/websocket.js

@@ -0,0 +1,134 @@
+
+/**
+ * Module dependencies.
+ */
+
+var Transport = require('../transport');
+var parser = require('engine.io-parser');
+var util = require('util');
+var debug = require('debug')('engine:ws');
+
+/**
+ * Export the constructor.
+ */
+
+module.exports = WebSocket;
+
+/**
+ * WebSocket transport
+ *
+ * @param {http.IncomingMessage}
+ * @api public
+ */
+
+function WebSocket (req) {
+  Transport.call(this, req);
+  var self = this;
+  this.socket = req.websocket;
+  this.socket.on('message', this.onData.bind(this));
+  this.socket.once('close', this.onClose.bind(this));
+  this.socket.on('error', this.onError.bind(this));
+  this.socket.on('headers', onHeaders);
+  this.writable = true;
+  this.perMessageDeflate = null;
+
+  function onHeaders (headers) {
+    self.emit('headers', headers);
+  }
+}
+
+/**
+ * Inherits from Transport.
+ */
+
+util.inherits(WebSocket, Transport);
+
+/**
+ * Transport name
+ *
+ * @api public
+ */
+
+WebSocket.prototype.name = 'websocket';
+
+/**
+ * Advertise upgrade support.
+ *
+ * @api public
+ */
+
+WebSocket.prototype.handlesUpgrades = true;
+
+/**
+ * Advertise framing support.
+ *
+ * @api public
+ */
+
+WebSocket.prototype.supportsFraming = true;
+
+/**
+ * Processes the incoming data.
+ *
+ * @param {String} encoded packet
+ * @api private
+ */
+
+WebSocket.prototype.onData = function (data) {
+  debug('received "%s"', data);
+  Transport.prototype.onData.call(this, data);
+};
+
+/**
+ * Writes a packet payload.
+ *
+ * @param {Array} packets
+ * @api private
+ */
+
+WebSocket.prototype.send = function (packets) {
+  var self = this;
+
+  for (var i = 0; i < packets.length; i++) {
+    var packet = packets[i];
+    parser.encodePacket(packet, self.supportsBinary, send);
+  }
+
+  function send (data) {
+    debug('writing "%s"', data);
+
+    // always creates a new object since ws modifies it
+    var opts = {};
+    if (packet.options) {
+      opts.compress = packet.options.compress;
+    }
+
+    if (self.perMessageDeflate) {
+      var len = 'string' === typeof data ? Buffer.byteLength(data) : data.length;
+      if (len < self.perMessageDeflate.threshold) {
+        opts.compress = false;
+      }
+    }
+
+    self.writable = false;
+    self.socket.send(data, opts, onEnd);
+  }
+
+  function onEnd (err) {
+    if (err) return self.onError('write error', err.stack);
+    self.writable = true;
+    self.emit('drain');
+  }
+};
+
+/**
+ * Closes the transport.
+ *
+ * @api private
+ */
+
+WebSocket.prototype.doClose = function (fn) {
+  debug('closing');
+  this.socket.close();
+  fn && fn();
+};