/**
* 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。