Yii源码阅读笔记（二十八）

Yii/web中的Controller类，实现参数绑定，启动csrf验证功能，重定向页面功能：

 namespace yii\web;

 use Yii;
 use yii\base\InlineAction;
 use yii\helpers\Url;

 /**
  * Controller is the base class of web controllers.
  *
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @since 2.0
  */
 class Controller extends \yii\base\Controller
 {
     /**
      * @var boolean whether to enable CSRF validation for the actions in this controller.
      * @var boolean 是否启动CSRF验证标记
      * CSRF validation is enabled only when both this property and [[Request::enableCsrfValidation]] are true.
      */
     public $enableCsrfValidation = true;
     /**
      * @var array the parameters bound to the current action.
      * @var array 绑定到当前操作的参数
      */
     public $actionParams = [];

     /**
      * Renders a view in response to an AJAX request.
      * 这个渲染的结果用来作为ajax请求的的响应
      *
      * This method is similar to [[renderPartial()]] except that it will inject into
      * the rendering result with JS/CSS scripts and files which are registered with the view.
      * For this reason, you should use this method instead of [[renderPartial()]] to render
      * a view to respond to an AJAX request.
      * 这个方法和renderPartial类似，但这个返回的结果中会包含css/js以及其它在view中注册的文件。
      *
      * @param string $view the view name. Please refer to [[render()]] on how to specify a view name.
      * @param array $params the parameters (name-value pairs) that should be made available in the view.
      * @return string the rendering result.
      */
     public function renderAjax($view, $params = [])
     {
         return $this->getView()->renderAjax($view, $params, $this);
     }

     /**
      * Binds the parameters to the action.
      * 基类的 action 中绑定参数功能的实现
      * This method is invoked by [[\yii\base\Action]] when it begins to run with the given parameters.
      * This method will check the parameter names that the action requires and return
      * the provided parameters according to the requirement. If there is any missing parameter,
      * an exception will be thrown.
      * 根据action中定义的参数，从$_GET中取对应的值，
      * 如果没有，则抛出异常
      * @param \yii\base\Action $action the action to be bound with parameters
      * @param array $params the parameters to be bound to the action
      * @return array the valid parameters that the action can run with.
      * @throws BadRequestHttpException if there are missing or invalid parameters.
      */
     public function bindActionParams($action, $params)
     {
         if ($action instanceof InlineAction) {//如果action继承InlineAction
             $method = new \ReflectionMethod($this, $action->actionMethod);//通过反射得到动作action的方法信息
         } else {
             $method = new \ReflectionMethod($action, 'run');//如果action继承Action基类，通过反射得到动作action的方法信息，并实现里面的run方法
         }

         $args = [];
         $missing = [];
         $actionParams = [];
         foreach ($method->getParameters() as $param) {
              //获取在action中定义的参数的名称
             $name = $param->getName();
             if (array_key_exists($name, $params)) {
                 if ($param->isArray()) {//如果参数是数组类型的，如果从传入的参数中取得的数据是数组则返回，否则将得到的参数转换为数组
                     $args[] = $actionParams[$name] = (array) $params[$name];
                 } elseif (!is_array($params[$name])) {//如果不是数组，直接返回传入的参数中对应的结果
                     $args[] = $actionParams[$name] = $params[$name];
                 } else {
                     throw new BadRequestHttpException(Yii::t('yii', 'Invalid data received for parameter "{param}".', [
                         'param' => $name,
                     ]));
                 }
                 unset($params[$name]);
             } elseif ($param->isDefaultValueAvailable()) { //如果默认有默认值取默认值
                 $args[] = $actionParams[$name] = $param->getDefaultValue();
             } else {//action中定义的参数没有在传入的参数中找到，标记的missing中
                 $missing[] = $name;
             }
         }

         if (!empty($missing)) {//action中的参数有缺少，抛出异常
             throw new BadRequestHttpException(Yii::t('yii', 'Missing required parameters: {params}', [
                 'params' => implode(', ', $missing),
             ]));
         }

         $this->actionParams = $actionParams;

         return $args;
     }

     /**
      * @inheritdoc  重写基类的beforeAction
      */
     public function beforeAction($action)
     {
         if (parent::beforeAction($action)) {
             //父类的beforAction方法执行成功后，启动csrf验证功能
             if ($this->enableCsrfValidation && Yii::$app->getErrorHandler()->exception === null && !Yii::$app->getRequest()->validateCsrfToken()) {
                 throw new BadRequestHttpException(Yii::t('yii', 'Unable to verify your data submission.'));
             }
             return true;
         }

         return false;
     }

     /**
      * Redirects the browser to the specified URL.
      * 重定向方法[[Response::redirect()]]的短方法
      * This method is a shortcut to [[Response::redirect()]].
      *
      * You can use it in an action by returning the [[Response]] directly:
      * 下面的例子是重定向到longin
      * ```php
      * // stop executing this action and redirect to login page
      * return $this->redirect(['login']);
      * ```
      *
      * @param string|array $url the URL to be redirected to. This can be in one of the following formats:
      * @param string|array $url 重定向的URL，有下列三种形式
      *
      * - a string representing a URL (e.g. "http://example.com")
      *   一个字符串URL
      * - a string representing a URL alias (e.g. "@example.com")
      *   别名形式的URL
      * - an array in the format of `[$route, ...name-value pairs...]` (e.g. `['site/index', 'ref' => 1]`)
      *   数组，第一个元素为生成路径的参数，后面的元素为链接中传递的参数
      *   [[Url::to()]] will be used to convert the array into a URL.
      *
      * Any relative URL will be converted into an absolute one by prepending it with the host info
      * of the current request.
      * 如果传入的是相对的url，都会根据当前请求的host info 转换为绝对url
      *
      * @param integer $statusCode the HTTP status code. Defaults to 302.
      * See <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html>
      * for details about HTTP status code
      * @return Response the current response object
      */
     public function redirect($url, $statusCode = 302)
     {
         return Yii::$app->getResponse()->redirect(Url::to($url), $statusCode);
     }

     /**
      * Redirects the browser to the home page.
      * 重定向到首页
      *
      * You can use this method in an action by returning the [[Response]] directly:
      *
      * ```php
      * // stop executing this action and redirect to home page
      * return $this->goHome();
      * ```
      *
      * @return Response the current response object
      */
     public function goHome()
     {
         return Yii::$app->getResponse()->redirect(Yii::$app->getHomeUrl());
     }

     /**
      * Redirects the browser to the last visited page.
      * 返回上一页
      *
      * You can use this method in an action by returning the [[Response]] directly:
      *
      * ```php
      * // stop executing this action and redirect to last visited page
      * return $this->goBack();
      * ```
      *
      * For this function to work you have to [[User::setReturnUrl()|set the return URL]] in appropriate places before.
      *
      * @param string|array $defaultUrl the default return URL in case it was not set previously.
      * If this is null and the return URL was not set previously, [[Application::homeUrl]] will be redirected to.
      * Please refer to [[User::setReturnUrl()]] on accepted format of the URL.
      * @return Response the current response object
      * @see User::getReturnUrl()
      */
     public function goBack($defaultUrl = null)
     {
         return Yii::$app->getResponse()->redirect(Yii::$app->getUser()->getReturnUrl($defaultUrl));
     }

     /**
      * Refreshes the current page.
      * 刷新页面
      * This method is a shortcut to [[Response::refresh()]].
      *
      * You can use it in an action by returning the [[Response]] directly:
      *
      * ```php
      * // stop executing this action and refresh the current page
      * return $this->refresh();
      * ```
      *
      * @param string $anchor the anchor that should be appended to the redirection URL.
      * Defaults to empty. Make sure the anchor starts with '#' if you want to specify it.
      * @return Response the response object itself
      */
     public function refresh($anchor = '')
     {
         return Yii::$app->getResponse()->redirect(Yii::$app->getRequest()->getUrl() . $anchor);
     }
 }