Yii源码阅读笔记（十二）

  1 namespace yii\base;
  2 
  3 use Yii;
  4 
  5 /**
  6  * Action is the base class for all controller action classes.
  7  * Action是所有控制器方法的基类
  8  * Action provides a way to reuse action method code. An action method in an Action
  9  * class can be used in multiple controllers or in different projects.
 10  * Action提供了一种重用代码的方法，一个Action类中的方法可以被多个控制器或不同的项目调用
 11  * Derived classes must implement a method named `run()`. This method
 12  * will be invoked by the controller when the action is requested.
 13  * 驱动类必须实现run（）方法，该方法在action被请求的时候被控制器调用
 14  * The `run()` method can have parameters which will be filled up
 15  * with user input values automatically according to their names.
 16  * 如果请求带有参数，run方法会自动带参数运行，例如：
 17  * For example, if the `run()` method is declared as follows:
 18  *
 19  * ```php
 20  * public function run($id, $type = ‘book‘) { ... }
 21  * ```
 22  *
 23  * And the parameters provided for the action are: `[‘id‘ => 1]`.
 24  * Then the `run()` method will be invoked as `run(1)` automatically.
 25  *
 26  * @property string $uniqueId The unique ID of this action among the whole application. This property is
 27  * read-only.
 28  *
 29  * @author Qiang Xue <qiang.xue@gmail.com>
 30  * @since 2.0
 31  */
 32 class Action extends Component
 33 {
 34     /**
 35      * @var action的ID
 36      */
 37     public $id;
 38     /**
 39      * @var Controller|\yii\web\Controller 当前action的控制器
 40      */
 41     public $controller;
 42 
 43 
 44     /**
 45      * Constructor.
 46      * 构造函数，用于初始化action 的ID和控制器，并且调用component的构造方法初始化对象
 47      * 
 48      * @param string $id the ID of this action
 49      * @param Controller $controller the controller that owns this action
 50      * @param array $config name-value pairs that will be used to initialize the object properties
 51      */
 52     public function __construct($id, $controller, $config = [])
 53     {
 54         $this->id = $id;
 55         $this->controller = $controller;
 56         parent::__construct($config);
 57     }
 58 
 59     /**
 60      * Returns the unique ID of this action among the whole application.
 61      * 用于取得当前action的唯一ID  形式为controller ID/action ID
 62      * @return string the unique ID of this action among the whole application.
 63      */
 64     public function getUniqueId()
 65     {
 66         return $this->controller->getUniqueId() . ‘/‘ . $this->id;
 67     }
 68 
 69     /**
 70      * Runs this action with the specified parameters.
 71      * This method is mainly invoked by the controller.
 72      * 用指定的参数运行，该方法主要被控制器调用
 73      *
 74      * @param array $params the parameters to be bound to the action‘s run() method.
 75      * @return mixed the result of the action
 76      * @throws InvalidConfigException if the action class does not have a run() method
 77      */
 78     public function runWithParams($params)
 79     {
 80         if (!method_exists($this, ‘run‘)) {//如果run方法不存在，抛出异常
 81             throw new InvalidConfigException(get_class($this) . ‘ must define a "run()" method.‘);
 82         }
 83         $args = $this->controller->bindActionParams($this, $params);//绑定参数
 84         Yii::trace(‘Running action: ‘ . get_class($this) . ‘::run()‘, __METHOD__);//记录trace信息
 85         if (Yii::$app->requestedParams === null) {
 86             Yii::$app->requestedParams = $args;//如果是命令行运行，按命令行方式获取参数
 87         }
 88         if ($this->beforeRun()) {//调用run的前置操作
 89             $result = call_user_func_array([$this, ‘run‘], $args);//用php内置函数带参数执行run方法
 90             $this->afterRun();//调用后置操作
 91 
 92             return $result;//返回结果
 93         } else {
 94             return null;
 95         }
 96     }
 97 
 98     /**
 99      * This method is called right before `run()` is executed.
100      * You may override this method to do preparation work for the action run.
101      * If the method returns false, it will cancel the action.
102      * run方法的前置方法，通常在子类中重写来实现某些前置功能
103      * 
104      * @return boolean whether to run the action.
105      */
106     protected function beforeRun()
107     {
108         return true;
109     }
110 
111     /**
112      * This method is called right after `run()` is executed.
113      * You may override this method to do post-processing work for the action run.
114      * run方法的后置方法，通常在子类中重写来实现某些后置功能
115      * 
116      */
117     protected function afterRun()
118     {
119     }
120 }