Yii源码阅读笔记（十）

  1 namespace yii\base;
  2 
  3 use Yii;
  4 
  5 /**
  6  * Controller is the base class for classes containing controller logic.
  7  * 控制器，是所用控制器类的基类
  8  * 
  9  * @property Module[] $modules  只读属性  当前控制器的所有模块
 10  * 
 11  * @property string $route  (module ID, controller ID and action ID)  当前请求的路径  只读属性 可以获取到请求的路径
 12  * 
 13  * @property string $uniqueId  以module ID（如果有的话） 为前缀的controller ID  应该是唯一标识的作用
 14  * 
 15  * @property View|\yii\web\View $view 视图 object 用来传递视图或视图文件.
 16  * 
 17  * @property string $viewPath 包含当前控制器的视图目录.
 18  *
 19  * @author Qiang Xue <qiang.xue@gmail.com>
 20  * @since 2.0
 21  */
 22 class Controller extends Component implements ViewContextInterface
 23 {
 24     /**
 25      * @event ActionEvent an event raised right before executing a controller action.
 26      * You may set [[ActionEvent::isValid]] to be false to cancel the action execution.
 27      * 在执行beforeAction方法时触发的事件，如果对事件的isValid属性设置为false，将取消action的执行
 28      */
 29     const EVENT_BEFORE_ACTION = ‘beforeAction‘;
 30     /**
 31      * @event ActionEvent an event raised right after executing a controller action.
 32      * 在执行afterAction方法是触发的事件
 33      */
 34     const EVENT_AFTER_ACTION = ‘afterAction‘;
 35 
 36     /**
 37      * @var string the ID of this controller.
 38      * 控制器id，
 39      */
 40     public $id;
 41     /**
 42      * @var Module $module the module that this controller belongs to.
 43      * 所属模块
 44      */
 45     public $module;
 46     /**
 47      * @var string the ID of the action that is used when the action ID is not specified
 48      * in the request. Defaults to ‘index‘.
 49      * 控制器中默认动作，默认为index
 50      */
 51     public $defaultAction = ‘index‘;
 52     /**
 53      * @var string|boolean the name of the layout to be applied to this controller‘s views.
 54      * This property mainly affects the behavior of [[render()]].
 55      * Defaults to null, meaning the actual layout value should inherit that from [[module]]‘s layout value.
 56      * If false, no layout will be applied.
 57      * 布局文件，如果设置为false，则不使用布局文件
 58      */
 59     public $layout;
 60     /**
 61      * @var Action the action that is currently being executed. This property will be set
 62      * by [[run()]] when it is called by [[Application]] to run an action.
 63      * 当前下面执行的action，可在事件中根据这个action来执行不同的操作
 64      */
 65     public $action;
 66 
 67     /**
 68      * @var View the view object that can be used to render views or view files.
 69      * 视图对象，用来定义输出的视图文件
 70      */
 71     private $_view;
 72     /**
 73      * @var string the root directory that contains view files for this controller.
 74      */
 75     private $_viewPath;
 76 
 77 
 78     /**
 79      * @param string $id 当前控制器的ID
 80      * @param Module $module 当前控制器的模块
 81      * @param array $config 初始化对像时的配置文件
 82      */
 83     public function __construct($id, $module, $config = [])
 84     {
 85         //初始化指定控制器id，模块，根据配置文件初始化控制器对象
 86         $this->id = $id;
 87         $this->module = $module;
 88         parent::__construct($config);
 89     }
 90 
 91     /**
 92      * Declares external actions for the controller.
 93      * 定义action   声明控制器的外部操作
 94      * This method is meant to be overwritten to declare external actions for the controller.
 95      * It should return an array, with array keys being action IDs, and array values the corresponding
 96      * action class names or action configuration arrays. For example,
 97      * 这个用来指定独立的action，返回格式为name-value的数组，name为action的id,value为action类的实现，如：
 98      *
 99      * ```php
100      * return [
101      *     ‘action1‘ => ‘app\components\Action1‘,
102      *     ‘action2‘ => [
103      *         ‘class‘ => ‘app\components\Action2‘,
104      *         ‘property1‘ => ‘value1‘,
105      *         ‘property2‘ => ‘value2‘,
106      *     ],
107      * ];
108      * ```
109      *
110      * [[\Yii::createObject()]] will be used later to create the requested action
111      * using the configuration provided here.
112      * 这个主要是用于在子类中重写
113      */
114     
115     public function actions()
116     {
117         return [];
118     }
119 
120     /**
121      * Runs an action within this controller with the specified action ID and parameters.
122      * If the action ID is empty, the method will use [[defaultAction]].
123      * $id 为action的id,也就是操作的名称，如定义的actionIndex，那么id就为Index。
124      * 如果没有定义 action ID，就会调用默认的操作，例如常用的index
125      * 
126      * @param string $id 操作id，也就是操作名
127      * @param array $params the parameters (name-value pairs) to be passed to the action.
128      * @return mixed the result of the action.
129      * @throws InvalidRouteException if the requested action ID cannot be resolved into an action successfully.
130      * @see createAction()
131      */
132     public function runAction($id, $params = [])
133     {
134         //创建action
135         $action = $this->createAction($id);
136         if ($action === null) {
137             //创建action失败，抛出异常
138             throw new InvalidRouteException(‘Unable to resolve the request: ‘ . $this->getUniqueId() . ‘/‘ . $id);
139         }
140         //写入trace信息
141         Yii::trace(‘Route to run: ‘ . $action->getUniqueId(), __METHOD__);
142 
143         if (Yii::$app->requestedAction === null) {
144             Yii::$app->requestedAction = $action;//不知道这个是干嘛用的0.0
145         }
146 
147         $oldAction = $this->action;//将action中的信息保存到oldAction
148         $this->action = $action; //将当前的action写入action属性中
149         //用来保存当前控制器的所有父模块，顺序为由子模块到父模块
150         $modules = [];
151         $runAction = true;
152 
153          /*
154          * 获取当前控制器的所有的模块，并执行每个模块的beforeAction来检查当前的action是否可以执行，
155          * 注意：getModules返回的数组顺序为：从父模块到子模块，
156          * 所以在执行beforeAction的时候，先检查最外层的父模块，然后检查子模块。
157          * 
158          * 然而在执行afterAction的时候，顺序就反过来了，先执行子模块，最后执行父模块。
159          * 
160          */
161         foreach ($this->getModules() as $module) {
162             if ($module->beforeAction($action)) {
163                 array_unshift($modules, $module);
164             } else {
165                 $runAction = false;
166                 break;
167             }
168         }
169 
170         $result = null;
171          //如果所有的父模块都满足执行的条件
172         if ($runAction && $this->beforeAction($action)) {//判断当前控制器中beforeAction
173             // 由生成的action对象来执行runWithParams方法
174             $result = $action->runWithParams($params);
175                 //执行完后，再执行afterAction方法 
176             $result = $this->afterAction($action, $result);
177 
178              //执行所有父模块的afterAction
179             foreach ($modules as $module) {
180                 /* @var $module Module */
181                 $result = $module->afterAction($action, $result);
182             }
183         }
184         $this->action = $oldAction;//有什么用呢？，看完后面的在回头看吧
185 
186         return $result;
187     }