server/modules.js

   1 var events = require('events'),
   2         util = require('util');
   3
   4
   5 // Where events are bound to
   6 var active_publisher;
   7
   8
   9 // Create a publisher to allow event subscribing
  10 function Publisher (obj) {
  11         var EventPublisher = function modulePublisher() {};
  12         util.inherits(EventPublisher, events.EventEmitter);
  13
  14         return new EventPublisher();
  15 }
  16
  17
  18 // Register an already created Publisher() as the active instance
  19 function registerPublisher (obj) {
  20         active_publisher = obj;
  21 }
  22
  23
  24
  25
  26 /**
  27  * Module object
  28  * To be created by modules to bind to server events
  29  */
  30 function Module (module_name) {}
  31
  32
  33 // Holder for all the bound events by this module
  34 Module.prototype._events = {};
  35
  36
  37 // Keep track of this modules events and bind
  38 Module.prototype.subscribe = function (event_name, fn) {
  39         this._events[event_name] = this._events[event_name] || [];
  40         this._events[event_name].push(fn);
  41
  42         active_publisher.on(event_name, fn);
  43 };
  44
  45
  46 // Keep track of this modules events and bind once
  47 Module.prototype.once = function (event_name, fn) {
  48         this._events[event_name] = this._events[event_name] || [];
  49         this._events[event_name].push(fn);
  50
  51         active_publisher.once(event_name, fn);
  52 };
  53
  54
  55 // Remove any events by this module only
  56 Module.prototype.unsubscribe = function (event_name, fn) {
  57         var idx;
  58
  59         if (typeof event_name === 'undefined') {
  60                 // Remove all events
  61                 this._events = [];
  62
  63         } else if (typeof fn === 'undefined') {
  64                 // Remove all of 1 event type
  65                 delete this._events[event_name];
  66
  67         } else {
  68                 // Remove a single event + callback
  69                 for (idx in (this._events[event_name] || [])) {
  70                         if (this._events[event_name][idx] === fn) {
  71                                 delete this._events[event_name][idx];
  72                         }
  73                 }
  74         }
  75
  76         active_publisher.removeListener(event_name, fn);
  77 };
  78
  79
  80 // Clean up anything used by this module
  81 Module.prototype.dispose = function () {
  82         this.unsubscribe();
  83 };
  84
  85
  86
  87
  88
  89
  90 module.exports = {
  91         // Objects
  92         Module: Module,
  93         Publisher: Publisher,
  94
  95         // Methods
  96         registerPublisher: registerPublisher
  97 };