yii验证系统学习记录，基于yiicms（二）

 /**
      * Validates the specified object.
      * @param \yii\base\Model $model the data model being validated
      * @param array|null $attributes the list of attributes to be validated.
      * Note that if an attribute is not associated with the validator - it will be
      * ignored. If this parameter is null, every attribute listed in [[attributes]] will be validated.
      */
     public function validateAttributes($model, $attributes = null)
     {
         //传入的是被验证的属性。属性很可能是某一具体场景下的需验证属性
         //这里进行验证器过滤，必须同时在场景中和验证器中都有，才会接着去验证。
         if (is_array($attributes)) {
             $newAttributes = [];
             foreach ($attributes as $attribute) {
                 if (in_array($attribute, $this->getAttributeNames(), true)) {
                     $newAttributes[] = $attribute;
                 }
             }
             $attributes = $newAttributes;
         } else {
             $attributes = $this->getAttributeNames();
         }

         foreach ($attributes as $attribute) {
             $skip = $this->skipOnError && $model->hasErrors($attribute)
                 || $this->skipOnEmpty && $this->isEmpty($model->$attribute);
　　　　　　　　　//可以肯定的是在一般场景下$skip就是false，因此下面的判断是会执行的，而$this->when是rules里传入的回调，一般没使用这个回调，因此为null，
　　　　　　　　　//继续执行$this->validateAttribute($model, $attribute);

             if (!$skip) {
                 //此处when默认为null，也即用户在验证规则里没设置。继续下一步
                 if ($this->when === null || call_user_func($this->when, $model, $attribute)) {
                     $this->validateAttribute($model, $attribute);
                 }
             }
         }
     }

这个验证指定对象的验证器在（一）介绍过了，这里贴一下代码。继续执行$this->validateAttribute($model, $attribute);代码如下：

 /**
      * Validates a single attribute.
      * Child classes must implement this method to provide the actual validation logic.
      * @param \yii\base\Model $model the data model to be validated
      * @param string $attribute the name of the attribute to be validated.
      */
     public function validateAttribute($model, $attribute)
     {
         $result = $this->validateValue($model->$attribute);
         if (!empty($result)) {
             $this->addError($model, $attribute, $result[0], $result[1]);
         }
     }

验证一个单独属性，子类必须集成这个方法来提供实际的验证逻辑，$model是被验证的model，$attribute是被验证的属性。哦，原来是在这添加的错误，执行完后，validate方法会返回这个错误状态，有错或无错。进这个validateValue方法看一下。

 /**
      * Validates a value.
      * A validator class can implement this method to support data validation out of the context of a data model.
      * @param mixed $value the data value to be validated.
      * @return array|null the error message and the parameters to be inserted into the error message.
      * Null should be returned if the data is valid.
      * @throws NotSupportedException if the validator does not supporting data validation without a model
      */
     protected function validateValue($value)
     {
         throw new NotSupportedException(get_class($this) . ' does not support validateValue().');
     }

这个方法是个虚拟方法，不能直接被调用，必须在子类中实现该方法用以支持数据模型上下文的验证。$value是被验证的值，返回的错误信息，参数会插入错误信息，null返回代表数据不可用。如果验证器不支持数据验证模型将抛出错误。

咱们以required验证器为例：

 <?php
 /**
  * @link http://www.yiiframework.com/
  * @copyright Copyright (c) 2008 Yii Software LLC
  * @license http://www.yiiframework.com/license/
  */

 namespace yii\validators;

 use Yii;

 /**
  * RequiredValidator validates that the specified attribute does not have null or empty value.
  *
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @since 2.0
  */
 class RequiredValidator extends Validator
 {
     /**
      * @var bool whether to skip this validator if the value being validated is empty.
      */
     public $skipOnEmpty = false;
     /**
      * @var mixed the desired value that the attribute must have.
      * If this is null, the validator will validate that the specified attribute is not empty.
      * If this is set as a value that is not null, the validator will validate that
      * the attribute has a value that is the same as this property value.
      * Defaults to null.
      * @see strict
      */
     public $requiredValue;
     /**
      * @var bool whether the comparison between the attribute value and [[requiredValue]] is strict.
      * When this is true, both the values and types must match.
      * Defaults to false, meaning only the values need to match.
      * Note that when [[requiredValue]] is null, if this property is true, the validator will check
      * if the attribute value is null; If this property is false, the validator will call [[isEmpty]]
      * to check if the attribute value is empty.
      */
     public $strict = false;
     /**
      * @var string the user-defined error message. It may contain the following placeholders which
      * will be replaced accordingly by the validator:
      *
      * - `{attribute}`: the label of the attribute being validated
      * - `{value}`: the value of the attribute being validated
      * - `{requiredValue}`: the value of [[requiredValue]]
      */
     public $message;

     /**
      * @inheritdoc
      */
     public function init()
     {
         parent::init();
         if ($this->message === null) {
             $this->message = $this->requiredValue === null ? Yii::t('yii', '{attribute} cannot be blank.')
                 : Yii::t('yii', '{attribute} must be "{requiredValue}".');
         }
     }

     /**
      * @inheritdoc
      */
     protected function validateValue($value)
     {
         if ($this->requiredValue === null) {
             if ($this->strict && $value !== null || !$this->strict && !$this->isEmpty(is_string($value) ? trim($value) : $value)) {
                 return null;
             }
         } elseif (!$this->strict && $value == $this->requiredValue || $this->strict && $value === $this->requiredValue) {
             return null;
         }
         if ($this->requiredValue === null) {
             return [$this->message, []];
         } else {
             return [$this->message, [
                 'requiredValue' => $this->requiredValue,
             ]];
         }
     }

     /**
      * @inheritdoc
      */
     public function clientValidateAttribute($model, $attribute, $view)
     {
         ValidationAsset::register($view);
         $options = $this->getClientOptions($model, $attribute);

         return 'yii.validation.required(value, messages, ' . json_encode($options, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE) . ');';
     }

     /**
      * @inheritdoc
      */
     public function getClientOptions($model, $attribute)
     {
         $options = [];
         if ($this->requiredValue !== null) {
             $options['message'] = $this->formatMessage($this->message, [
                 'requiredValue' => $this->requiredValue,
             ]);
             $options['requiredValue'] = $this->requiredValue;
         } else {
             $options['message'] = $this->message;
         }
         if ($this->strict) {
             $options['strict'] = 1;
         }

         $options['message'] = $this->formatMessage($options['message'], [
             'attribute' => $model->getAttributeLabel($attribute),
         ]);

         return $options;
     }
 }

这个验证器用于验证非空非null属性。$skipOnEmpty，此时这个值设置为false，而不是基类validator上的true，也就是不跳过空值。$requiredValue是属性必须有的期待值，如果为null，验证器将验证指定的属性是否为空。如果不为空，那就验证跟该值指定的属性同名的属性。默认是null。$strict用来指定$requiredValue给定属性值跟传入属性值是否完全相同，如果为真，类型和值必须都相同。默认为假，只检查值，注意当requiredValue为null，如果这个属性为真，验证器将检查属性值是否为null，如果属性为false，验证器就会调用isEmpty检查属性值是否为空。$message是用户定义的错误信息，如果包含下面的占位符将根据规则进行替换。

* - `{attribute}`: the label of the attribute being validated

* - `{value}`: the value of the attribute being validated

* - `{requiredValue}`: the value of [[requiredValue]]

第一个被验证的属性标签，第二个被验证属性值，第三个被验证的requiredValue的值。