Merge pull request #91 from kbparagua/feature/before-callbacks

Feature/before callbacks

test_app/app/assets/javascripts/application.js

@@ -31,9 +31,29 @@
 var blank = function(){};
 
 Paloma.controller('Application', {
+
+  // before: [
+  //   'all -> logRequest',
+  //   'show index -> askUser changeBackground'
+  // ],
+
+  before: [
+    'all -> performThis',
+    'show -> doSomething'
+  ],
+
   index: function(){
     console.log('Inherited');
+  },
+
+  doSomething: function(){
+    console.log('Do something');
+  },
+
+  performThis: function(){
+    console.log('Perform This!');
   }
+
 });
 
 Paloma.controller('Main < Application', {
@@ -44,7 +64,7 @@ Paloma.controller('Main < Application', {
 });
 
 
-Paloma.controller('OtherMain', {
+Paloma.controller('OtherMain < Application', {
   show: blank,
   otherAction: blank,
   multiple_calls_2: blank

test_app/spec/javascripts/before_callback_performer_spec.js

@@ -0,0 +1,79 @@
+describe('Paloma.BeforeCallbackPerformer', function(){
+  describe('#perform(action)', function(){
+
+    var Controller = Paloma.controller('MyController', {
+      before: [
+        'all -> initialize doThat',
+        'singleCallback unknown -> doSomething',
+        'multiCallback -> doSomething doAnotherThing'
+      ],
+
+      initialize: function(){
+        this.didWhat = [];
+      },
+
+      did: function(what){ return this.didWhat.indexOf(what) >= 0; },
+
+      noCallback: function(){ console.log('I have no callback.'); },
+      singleCallback: function(){ console.log('Single callback.'); },
+      multiCallback: function(){ console.log('Multiple callbacks.')},
+
+      doThat: function(){ this.didWhat.push('that'); },
+      doSomething: function(){ this.didWhat.push('something'); },
+      doAnotherThing: function(){ this.didWhat.push('anotherThing') }
+    });
+
+    function itPerformsCallbackForAll(controller){
+      it('performs callback for all', function(){
+        expect( controller.did('that') ).toBeTruthy();
+      });
+    };
+
+    describe('when there is no matched callback', function(){
+      var controller = new Controller(),
+          performer = new Paloma.BeforeCallbackPerformer(controller);
+
+      performer.perform('noCallback');
+
+      it('will not perform any callback', function(){
+        expect( controller.did('something') ).toBeFalsy();
+      });
+
+      itPerformsCallbackForAll(controller);
+    });
+
+    describe('when there is one matched callback', function(){
+      var controller = new Controller(),
+          performer = new Paloma.BeforeCallbackPerformer(controller);
+
+      performer.perform('singleCallback');
+
+      it('will perform the matched callback', function(){
+        expect( controller.did('something') ).toBeTruthy();
+      });
+
+      itPerformsCallbackForAll(controller);
+    });
+
+    describe('when there is more than one matched callbacks', function(){
+      var controller = new Controller(),
+          performer = new Paloma.BeforeCallbackPerformer(controller);
+
+      performer.perform('multiCallback');
+
+      it('will perform all the matched callbacks', function(){
+        expect( controller.did('something') && controller.did('anotherThing') ).
+          toBeTruthy();
+      });
+
+      it('will perform the callbacks in order of definition', function(){
+        expect(controller.didWhat).toEqual([
+          'that', 'something', 'anotherThing'
+        ]);
+      });
+
+      itPerformsCallbackForAll(controller);
+    });
+
+  });
+});

vendor/assets/javascripts/paloma/base_controller.js

@@ -1,3 +1,8 @@
 Paloma.BaseController = function(params){
   this.params = params;
 };
+
+Paloma.BaseController.prototype = {
+  before: []
+};
+

vendor/assets/javascripts/paloma/before_callback_performer.js

@@ -0,0 +1,69 @@
+Paloma.BeforeCallbackPerformer = function(controller){
+  this.controller = controller;
+  this.entries = controller.before;
+  this.action = null;
+};
+
+Paloma.BeforeCallbackPerformer.prototype = {
+
+  perform: function(action){
+    this.action = action;
+    this._executeCallbacks();
+  },
+
+  _executeCallbacks: function(){
+    for (var i = 0, n = this._callbacks().length; i < n; i++)
+      this._executeCallback( this._callbacks()[i] );
+  },
+
+  _executeCallback: function(name){
+    var callback = this.controller[name];
+    if (callback) callback.call(this.controller);
+  },
+
+  _callbacks: function(){
+    if (this._callbackList) return this._callbackList;
+
+    this._callbackList = [];
+
+    for (var i = 0, n = this.entries.length; i < n; i++){
+      var entry = this.entries[i];
+
+      this._callbackList =
+        this._callbackList.concat( this._getCallbacksIfForAction(entry) );
+    }
+
+    return this._callbackList;
+  },
+
+  _getCallbacksIfForAction: function(entry){
+    var parsedEntry = this._parseEntry(entry);
+
+    if (
+      this._actionIsOn(parsedEntry.actions) ||
+      this._allIsOn(parsedEntry.actions)
+    )
+      return parsedEntry.callbacks;
+
+    return [];
+  },
+
+  _actionIsOn: function(actions){
+    return actions.indexOf(this.action) != -1;
+  },
+
+  _allIsOn: function(actions){
+    return actions.indexOf('all') != -1;
+  },
+
+  _parseEntry: function(entry){
+    var parts = entry.split('->'),
+        data = {actions: [], callbacks: []};
+
+    if (parts[0]) data.actions = parts[0].trim().split(' ');
+    if (parts[1]) data.callbacks = parts[1].trim().split(' ');
+
+    return data;
+  }
+
+};

vendor/assets/javascripts/paloma/engine.js

@@ -40,10 +40,14 @@ Paloma.Engine.prototype = {
   },
 
   _executeActionOf: function(controller){
-    var callback = controller[ this._request.action ];
+    var action = controller[ this._request.action ];
+
+    if (action){
+      var callbackPerformer = new Paloma.BeforeCallbackPerformer(controller);
+      callbackPerformer.perform( this._request.action );
+
+      action.call(controller);
 
-    if (callback){
-      callback.call(controller);
       this._lastRequest.executed = true;
     }
   },

vendor/assets/javascripts/paloma/index.js

@@ -1,5 +1,6 @@
 //= require ./init.js
 //= require ./base_controller.js
 //= require ./controller_builder.js
+//= require ./before_callback_performer.js
 //= require ./engine.js
 //= require ./paloma.js