work.suroh.tk/node_modules/socket.io/lib/namespace.js

/**
 * Module dependencies.
 */

var Socket = require('./socket');
var Emitter = require('events').EventEmitter;
var parser = require('socket.io-parser');
var hasBin = require('has-binary2');
var debug = require('debug')('socket.io:namespace');

/**
 * Module exports.
 */

module.exports = exports = Namespace;

/**
 * Blacklisted events.
 */

exports.events = [
  'connect',    // for symmetry with client
  'connection',
  'newListener'
];

/**
 * Flags.
 */

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

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

var emit = Emitter.prototype.emit;

/**
 * Namespace constructor.
 *
 * @param {Server} server instance
 * @param {Socket} name
 * @api private
 */

function Namespace(server, name){
  this.name = name;
  this.server = server;
  this.sockets = {};
  this.connected = {};
  this.fns = [];
  this.ids = 0;
  this.rooms = [];
  this.flags = {};
  this.initAdapter();
}

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

Namespace.prototype.__proto__ = Emitter.prototype;

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

exports.flags.forEach(function(flag){
  Object.defineProperty(Namespace.prototype, flag, {
    get: function() {
      this.flags[flag] = true;
      return this;
    }
  });
});

/**
 * Initializes the `Adapter` for this nsp.
 * Run upon changing adapter by `Server#adapter`
 * in addition to the constructor.
 *
 * @api private
 */

Namespace.prototype.initAdapter = function(){
  this.adapter = new (this.server.adapter())(this);
};

/**
 * Sets up namespace middleware.
 *
 * @return {Namespace} self
 * @api public
 */

Namespace.prototype.use = function(fn){
  if (this.server.eio && this.name === '/') {
    debug('removing initial packet');
    delete this.server.eio.initialPacket;
  }
  this.fns.push(fn);
  return this;
};

/**
 * Executes the middleware for an incoming client.
 *
 * @param {Socket} socket that will get added
 * @param {Function} fn last fn call in the middleware
 * @api private
 */

Namespace.prototype.run = function(socket, fn){
  var fns = this.fns.slice(0);
  if (!fns.length) return fn(null);

  function run(i){
    fns[i](socket, function(err){
      // upon error, short-circuit
      if (err) return fn(err);

      // if no middleware left, summon callback
      if (!fns[i + 1]) return fn(null);

      // go on to next
      run(i + 1);
    });
  }

  run(0);
};

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

Namespace.prototype.to =
Namespace.prototype.in = function(name){
  if (!~this.rooms.indexOf(name)) this.rooms.push(name);
  return this;
};

/**
 * Adds a new client.
 *
 * @return {Socket}
 * @api private
 */

Namespace.prototype.add = function(client, query, fn){
  debug('adding socket to nsp %s', this.name);
  var socket = new Socket(this, client, query);
  var self = this;
  this.run(socket, function(err){
    process.nextTick(function(){
      if ('open' == client.conn.readyState) {
        if (err) return socket.error(err.data || err.message);

        // track socket
        self.sockets[socket.id] = socket;

        // it's paramount that the internal `onconnect` logic
        // fires before user-set events to prevent state order
        // violations (such as a disconnection before the connection
        // logic is complete)
        socket.onconnect();
        if (fn) fn();

        // fire user-set events
        self.emit('connect', socket);
        self.emit('connection', socket);
      } else {
        debug('next called after client was closed - ignoring socket');
      }
    });
  });
  return socket;
};

/**
 * Removes a client. Called by each `Socket`.
 *
 * @api private
 */

Namespace.prototype.remove = function(socket){
  if (this.sockets.hasOwnProperty(socket.id)) {
    delete this.sockets[socket.id];
  } else {
    debug('ignoring remove for %s', socket.id);
  }
};

/**
 * Emits to all clients.
 *
 * @return {Namespace} self
 * @api public
 */

Namespace.prototype.emit = function(ev){
  if (~exports.events.indexOf(ev)) {
    emit.apply(this, arguments);
    return this;
  }
  // set up packet object
  var args = Array.prototype.slice.call(arguments);
  var packet = {
    type: (this.flags.binary !== undefined ? this.flags.binary : hasBin(args)) ? parser.BINARY_EVENT : parser.EVENT,
    data: args
  };

  if ('function' == typeof args[args.length - 1]) {
    throw new Error('Callbacks are not supported when broadcasting');
  }

  var rooms = this.rooms.slice(0);
  var flags = Object.assign({}, this.flags);

  // reset flags
  this.rooms = [];
  this.flags = {};

  this.adapter.broadcast(packet, {
    rooms: rooms,
    flags: flags
  });

  return this;
};

/**
 * Sends a `message` event to all clients.
 *
 * @return {Namespace} self
 * @api public
 */

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

/**
 * Gets a list of clients.
 *
 * @return {Namespace} self
 * @api public
 */

Namespace.prototype.clients = function(fn){
  this.adapter.clients(this.rooms, fn);
  // reset rooms for scenario:
  // .in('room').clients() (GH-1978)
  this.rooms = [];
  return this;
};

/**
 * Sets the compress flag.
 *
 * @param {Boolean} compress if `true`, compresses the sending data
 * @return {Socket} self
 * @api public
 */

Namespace.prototype.compress = function(compress){
  this.flags.compress = compress;
  return this;
};

/**
 * Sets the binary flag
 *
 * @param {Boolean} Encode as if it has binary data if `true`, Encode as if it doesnt have binary data if `false`
 * @return {Socket} self
 * @api public
 */

 Namespace.prototype.binary = function (binary) {
   this.flags.binary = binary;
   return this;
 };