server/modules.js

   1 var events = require('events'),
   2     util = require('util'),
   3     _ = require('lodash'),
   4     EventPublisher = require('./plugininterface.js');
   5
   6
   7 /**
   8  * Publisher
   9  * The main point in which events are fired and bound to
  10  */
  11
  12 // Where events are bound to
  13 var active_publisher;
  14
  15
  16 // Create a publisher to allow event subscribing
  17 function Publisher (obj) {
  18     var EventPublisher = require('./plugininterface.js');
  19     return new EventPublisher();
  20 }
  21
  22
  23 // Register an already created Publisher() as the active instance
  24 function registerPublisher (obj) {
  25     active_publisher = obj;
  26 }
  27
  28
  29
  30
  31
  32
  33 /**
  34  * Keeping track of modules
  35  */
  36
  37 // Hold the loaded modules
  38 var registered_modules = [];
  39
  40 function loadModule (module_file) {
  41     var module,
  42         full_module_filename = global.config.module_dir + module_file;
  43
  44     // Get an instance of the module and remove it from the cache
  45     try {
  46         module = require(full_module_filename);
  47         delete require.cache[require.resolve(full_module_filename)];
  48     } catch (err) {
  49         // Module was not found
  50         return false;
  51     }
  52
  53     return module;
  54 }
  55
  56
  57 // Find a registered collection, .dispose() of it and remove it
  58 function unloadModule (module) {
  59     var found_module = false;
  60
  61     registered_modules = _.reject(registered_modules, function (registered_module) {
  62         if (module.toLowerCase() === registered_module.module_name.toLowerCase()) {
  63             found_module = true;
  64
  65             registered_module.dispose();
  66             return true;
  67         }
  68     });
  69
  70     return found_module;
  71 }
  72
  73
  74
  75
  76
  77
  78 /**
  79  * Module object
  80  * To be created by modules to bind to server events
  81  */
  82 function Module (module_name) {
  83     registered_modules.push(this);
  84     this.module_name = module_name;
  85
  86     // Holder for all the bound events by this module
  87     this._events = {};
  88 }
  89
  90
  91
  92 // Keep track of this modules events and bind
  93 Module.prototype.on = function (event_name, fn) {
  94     var internal_events = ['dispose'];
  95
  96     this._events[event_name] = this._events[event_name] || [];
  97     this._events[event_name].push(fn);
  98
  99     // If this is an internal event, do not propogate the event
 100     if (internal_events.indexOf(event_name) === -1) {
 101         active_publisher.on(event_name, fn);
 102     }
 103 };
 104
 105
 106 // Keep track of this modules events and bind once
 107 Module.prototype.once = function (event_name, fn) {
 108     this._events[event_name] = this._events[event_name] || [];
 109     this._events[event_name].push(fn);
 110
 111     active_publisher.once(event_name, fn);
 112 };
 113
 114
 115 // Remove any events by this module only
 116 Module.prototype.off = function (event_name, fn) {
 117     var idx;
 118
 119     if (typeof event_name === 'undefined') {
 120         // Remove all events
 121         this._events = [];
 122
 123     } else if (typeof fn === 'undefined') {
 124         // Remove all of 1 event type
 125         delete this._events[event_name];
 126
 127     } else {
 128         // Remove a single event + callback
 129         for (idx in (this._events[event_name] || [])) {
 130             if (this._events[event_name][idx] === fn) {
 131                 delete this._events[event_name][idx];
 132             }
 133         }
 134     }
 135
 136     active_publisher.off(event_name, fn);
 137 };
 138
 139
 140
 141 // Clean up anything used by this module
 142 Module.prototype.dispose = function () {
 143     // Call any dispose callbacks
 144     (this._events['dispose'] || []).forEach(function (callback) {
 145         callback();
 146     });
 147
 148     // Remove all bound event listeners
 149     this.off();
 150 };
 151
 152
 153
 154
 155
 156
 157 module.exports = {
 158     // Objects
 159     Module: Module,
 160     Publisher: Publisher,
 161
 162     // Methods
 163     registerPublisher: registerPublisher,
 164     load: loadModule,
 165     unload: unloadModule,
 166     getRegisteredModules: function () { return registered_modules; }
 167 };