yii2框架随笔3

今天开始阅读vendor/yiisoft/yii2/base/Action.php

<?php


namespace yiiase;//命名空间

use Yii;//加载Yii文件夹下的Yii.php

/**
 * Action is the base class for all controller action classes.
 *
 * Action provides a way to reuse action method code. An action method in an Action
 * class can be used in multiple controllers or in different projects.
 *
 * Derived classes must implement a method named `run()`. This method
 * will be invoked by the controller when the action is requested.
 * The `run()` method can have parameters which will be filled up
 * with user input values automatically according to their names.
 * For example, if the `run()` method is declared as follows:
 *
 * ```php
 * public function run($id, $type = 'book') { ... }
 * ```
 *
 * And the parameters provided for the action are: `['id' => 1]`.
 * Then the `run()` method will be invoked as `run(1)` automatically.
 *
 * @property string $uniqueId The unique ID of this action among the whole application. This property is
 * read-only.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @since 2.0
 */
/*此控制器是所有控制器动作的基类。
  此控制器提供了一种方法可以重复使用操作方法的代码，此操作方法类可以在多个控制器或不同的项目中使用。
　派生类必须实现一个名为run()的方法，这种方法在控制器被请求时调用。
　举个例子：run()调用声明如下所示：public function run($id,$type=’book'){}并且提供了操作的参数 ['id'=>1];
　所以当run(1),参数为1时自动调用run();
　此属性只读。
*/

//此类继承Component类，下面我们先看一下Component是什么类。（请转下一段代码)
class Action extends Component
{
    /**
     * @var string ID of the action
     */
    public $id;
    /**
     * @var Controller|yiiwebController the controller that owns this action
     */
    public $controller;


    /**
     * Constructor.
     *
     * @param string $id the ID of this action
     * @param Controller $controller the controller that owns this action
     * @param array $config name-value pairs that will be used to initialize the object properties
     */
    public function __construct($id, $controller, $config = [])
    {
        $this->id = $id;
        $this->controller = $controller;
        parent::__construct($config);
    }

    /**
     * Returns the unique ID of this action among the whole application.
     *
     * @return string the unique ID of this action among the whole application.
     */
    public function getUniqueId()
    {
        return $this->controller->getUniqueId() . '/' . $this->id;
    }

    /**
     * Runs this action with the specified parameters.
     * This method is mainly invoked by the controller.
     *
     * @param array $params the parameters to be bound to the action's run() method.
     * @return mixed the result of the action
     * @throws InvalidConfigException if the action class does not have a run() method
     */
    public function runWithParams($params)
    {
        if (!method_exists($this, 'run')) {
            throw new InvalidConfigException(get_class($this) . ' must define a "run()" method.');
        }
        $args = $this->controller->bindActionParams($this, $params);
        Yii::trace('Running action: ' . get_class($this) . '::run()', __METHOD__);
        if (Yii::$app->requestedParams === null) {
            Yii::$app->requestedParams = $args;
        }
        if ($this->beforeRun()) {
            $result = call_user_func_array([$this, 'run'], $args);
            $this->afterRun();

            return $result;
        } else {
            return null;
        }
    }

    /**
     * This method is called right before `run()` is executed.
     * You may override this method to do preparation work for the action run.
     * If the method returns false, it will cancel the action.
     *
     * @return boolean whether to run the action.
     */
    protected function beforeRun()
    {
        return true;
    }

    /**
     * This method is called right after `run()` is executed.
     * You may override this method to do post-processing work for the action run.
     */
    protected function afterRun()
    {
    }
}

我们接下来先重点了解一下Component.php

目录为：vendor/yiisoft/yii2/base/Component.php

<?php


namespace yiiase; //命名空间

use Yii;　　//加载相关的类

/**
* Component is the base class that implements the *property*, *event* and *behavior* features.
*
* Component provides the *event* and *behavior* features, in addition to the *property* feature which is implemented in
* its parent class [[Object]].
*
* Event is a way to "inject" custom code into existing code at certain places. For example, a comment object can trigger
* an "add" event when the user adds a comment. We can write custom code and attach it to this event so that when the event
* is triggered (i.e. comment will be added), our custom code will be executed.
*
* An event is identified by a name that should be unique within the class it is defined at. Event names are *case-sensitive*.
*
* One or multiple PHP callbacks, called *event handlers*, can be attached to an event. You can call [[trigger()]] to
* raise an event. When an event is raised, the event handlers will be invoked automatically in the order they were
* attached.
*
* To attach an event handler to an event, call [[on()]]:

*/

//组件是实现属性，事件和行为特点的基类。
组件提供事件行为，这是继承他父类Object的特点。

 事件是一种在特定的地方“注入”自定义代码到现有的代码。例如，
 当一个用户添加评论事件时，注释的对象可以触发。我们可以编写自定义代码，并将其附加到此事件，这样当事件被触发（即评论将被添加），

 我们的自定义代码会被执行，

 一个或多个php回调，称为为‘事件处理’。要触发一个事件处理，可以用on();举个例子。

* ```php
* $post->on('update', function ($event) {
* // 发送电子邮件通知。
* });

在上述例子中，一个匿名函数被连接到'update'事件后。

可以用以下类型的程序做处理：

* - anonymous function: `function ($event) { ... }`    ------匿名函数
* - object method: `[$object, 'handleAdd']`            ------对象方法

* - static class method: `['Page', 'handleAdd']`       ------静态类方法
* - global function: `'handleAdd'`                     ------全局函数  

class Component extends Object
{
    /**
     * @var array the attached event handlers (event name => handlers)
     */
　　//事件处理程序，是一个数组。（事件名称=>处理程序）

    private $_events = [];
    /**
     * @var Behavior[]|null the attached behaviors (behavior name => behavior). This is `null` when not initialized.
     */
　　//行为为空时的连接形式，(行为名称=>行为),未初始化的时候为null.

    private $_behaviors;


    /**
     * Returns the value of a component property.
     * This method will check in the following order and act accordingly:
     *
     *  - a property defined by a getter: return the getter result
     *  - a property of a behavior: return the behavior property value
     *
     * Do not call this method directly as it is a PHP magic method that
     * will be implicitly called when executing `$value = $component->property;`.
     * @param string $name the property name
     * @return mixed the property value or the value of a behavior's property
     * @throws UnknownPropertyException if the property is not defined
     * @throws InvalidCallException if the property is write-only.
     * @see __set()
     */
　　

/ **
     *返回一个组件的属性值。
     *这个方法将检查以下顺序并采取相应的行动：
     *
     * - 通过一个getter定义的属性：返回getter的结果
     * - 一个行为的属性：返回的行为属性值
     *
     *不要直接调用此方法，因为它是一个PHP魔术方法
     *将执行`

$value = $component->property;时调用

`。
     * @参数字符串$name属性名
     * @返回混合属性值或行为的属性的值
     *@throws UnknownPropertyException如果没有定义属性,抛出信息。
     *@throws InvalidCallException如果该属性是只写的。
     *@see__set（）

    public function __get($name)
    {
        $getter = 'get' . $name; //定义$getter
        if (method_exists($this, $getter)) { //如果$getter这种方法在这个对象中被调用，则返回TRUE.
            // read property, e.g. getName()
            return $this->$getter();  //调用$getter方法。
        } else {
            // behavior property
            $this->ensureBehaviors(); //否则调用此函数，作用是确保此组件声明这种行为。
            foreach ($this->_behaviors as $behavior) {
                if ($behavior->canGetProperty($name)) { //返回一个boolean类型的指示属性是否可读。
                    return $behavior->$name;　　//如果可读，返回name的值。
                }
            }
        }
        if (method_exists($this, 'set' . $name)) {//如果set.$name这种方法在这个对象中被调用，则返回TRUE.
            throw new InvalidCallException('Getting write-only property: ' . get_class($this) . '::' . $name); //获取只读属性
        } else {
            throw new UnknownPropertyException('Getting unknown property: ' . get_class($this) . '::' . $name); //如果没被调用，抛出异常信息：属性不明。(未完待续.....)
        }
    }