自製多個參數驗證（Custom validator for multiple attributes)
Yii 2.0 教學裡面已經解釋了怎麼設計自己的驗證，不過有些時候，你可能需要同時驗證多個互相關聯的參數。比方說，參數可能都很重要，難以抉擇哪個更加重要；或者規則比較複雜，導致參數之間會互相影響。
這邊，我們實做一個CustomValidator，來同時驗證多個參數。
1. 怎麼做
如果要檢查多個參數，預設會將所有的參數用相同的方式驗證。我們這邊使用不同的特性（trait），並覆蓋yii\base\Validator:validateAttributes()：
<?php
namespace app\components;
trait BatchValidationTrait
{
/**
* @var bool whether to validate multiple attributes at once
*/
public $batch = false;
/**
* Validates the specified object.
* @param \yii\base\Model $model the data model being validated.
* @param array|null $attributes the list of attributes to be validated.
* Note that if an attribute is not associated with the validator, or is is prefixed with `!` char - it will be
* ignored. If this parameter is null, every attribute listed in [[attributes]] will be validated.
*/
public function validateAttributes($model, $attributes = null)
{
if (is_array($attributes)) {
$newAttributes = [];
foreach ($attributes as $attribute) {
if (in_array($attribute, $this->attributes) || in_array('!' . $attribute, $this->attributes)) {
$newAttributes[] = $attribute;
}
}
$attributes = $newAttributes;
} else {
$attributes = [];
foreach ($this->attributes as $attribute) {
$attributes[] = $attribute[0] === '!' ? substr($attribute, 1) : $attribute;
}
}
foreach ($attributes as $attribute) {
$skip = $this->skipOnError && $model->hasErrors($attribute)
|| $this->skipOnEmpty && $this->isEmpty($model->$attribute);
if ($skip) {
// Skip validation if at least one attribute is empty or already has error
// (according skipOnError and skipOnEmpty options must be set to true
return;
}
}
if ($this->batch) {
// Validate all attributes at once
if ($this->when === null || call_user_func($this->when, $model, $attribute)) {
// Pass array with all attributes instead of one attribute
$this->validateAttribute($model, $attributes);
}
} else {
// Validate each attribute separately using the same validation logic
foreach ($attributes as $attribute) {
if ($this->when === null || call_user_func($this->when, $model, $attribute)) {
$this->validateAttribute($model, $attribute);
}
}
}
}
}
然後，我們建立自己的驗證類別，並使用剛剛的特性：
<?php
namespace app\components;
use yii\validators\Validator;
class CustomValidator extends Validator
{
use BatchValidationTrait;
}
如果我們希望即時驗證（inline validation），我們可以用相同的特性，但是改繼承即時驗證器：
<?php
namespace app\components;
use yii\validators\InlineValidator;
class CustomInlineValidator extends InlineValidator
{
use BatchValidationTrait;
}
之後，還有幾個地方要修改。
首先，換掉原本的InlineValidator，使用自製的CustomInlineValidator，我們需要覆蓋CustomValidator的[[\yii\validators\Validator::createValidator()]] 函式：
public static function createValidator($type, $model, $attributes, $params = [])
{
$params['attributes'] = $attributes;
if ($type instanceof \Closure || $model->hasMethod($type)) {
// method-based validator
// The following line is changed to use our CustomInlineValidator
$params['class'] = __NAMESPACE__ . '\CustomInlineValidator';
$params['method'] = $type;
} else {
if (isset(static::$builtInValidators[$type])) {
$type = static::$builtInValidators[$type];
}
if (is_array($type)) {
$params = array_merge($type, $params);
} else {
$params['class'] = $type;
}
}
return Yii::createObject($params);
}
最後，要在模型中支援我們的驗證，我們建立自製的特性，並覆蓋 [[\yii\base\Model::createValidators()]] 如下：
<?php
namespace app\components;
use yii\base\InvalidConfigException;
trait CustomValidationTrait
{
/**
* Creates validator objects based on the validation rules specified in [[rules()]].
* Unlike [[getValidators()]], each time this method is called, a new list of validators will be returned.
* @return ArrayObject validators
* @throws InvalidConfigException if any validation rule configuration is invalid
*/
public function createValidators()
{
$validators = new ArrayObject;
foreach ($this->rules() as $rule) {
if ($rule instanceof Validator) {
$validators->append($rule);
} elseif (is_array($rule) && isset($rule[0], $rule[1])) { // attributes, validator type
// The following line is changed in order to use our CustomValidator
$validator = CustomValidator::createValidator($rule[1], $this, (array) $rule[0], array_slice($rule, 2));
$validators->append($validator);
} else {
throw new InvalidConfigException('Invalid validation rule: a rule must specify both attribute names and validator type.');
}
}
return $validators;
}
}
現在，我們可以透過繼承CustomValidator，實做我們自己的驗證器ChildrenFundsValidator：
<?php
namespace app\validators;
use app\components\CustomValidator;
class ChildrenFundsValidator extends CustomValidator
{
public function validateAttribute($model, $attribute)
{
// 這邊 $attribute 不是單一參數，而是包含所有相關參數的陣列
$totalSalary = $this->personalSalary + $this->spouseSalary;
// 如果有配偶薪資，成人最小需要量加倍
$minAdultFunds = $this->spouseSalary ? self::MIN_ADULT_FUNDS * 2 : self::MIN_ADULT_FUNDS;
$childFunds = $totalSalary - $minAdultFunds;
if ($childFunds / $this->childrenCount < self::MIN_CHILD_FUNDS) {
$this->addError('*', '這個家庭的薪資不足以育兒');
}
}
}
因為$attribute為相關參數的列表，我們可使用迴圈來為所有需要加上錯誤訊息的參數進行處理：
foreach ($attribute as $singleAttribute) {
$this->addError($attribute, '這個家庭的薪資不足以育兒');
}
現在，我們可以在模型的驗證規則裡面，加上這個規則：
[
['personalSalary', 'spouseSalary', 'childrenCount'],
\app\validators\ChildrenFundsValidator::className(),
'batch' => `true`,
'when' => function ($model) {
return $model->childrenCount > 0;
}
],
即時驗證的程式碼則是：
[
['personalSalary', 'spouseSalary', 'childrenCount'],
'validateChildrenFunds',
'batch' => `true`,
'when' => function ($model) {
return $model->childrenCount > 0;
}
],
以及對應的驗證函式：
public function validateChildrenFunds($attribute, $params)
{
// 這邊 $attribute 不是單一參數，而是包含所有相關參數的陣列
$totalSalary = $this->personalSalary + $this->spouseSalary;
// 如果有配偶薪資，成人最小需要量加倍
$minAdultFunds = $this->spouseSalary ? self::MIN_ADULT_FUNDS * 2 : self::MIN_ADULT_FUNDS;
$childFunds = $totalSalary - $minAdultFunds;
if ($childFunds / $this->childrenCount < self::MIN_CHILD_FUNDS) {
$this->addError('childrenCount', '這個家庭的薪資不足以育兒');
}
}
2. 總結
這樣做的好處：
- 程式碼能更清楚表示出所有相關的參數，規則可讀性更高。
- 這種作法讓選項 [[yii\validators\Validator::skipOnError]] 和 [[yii\validators\Validator::skipOnEmpty]] 適用於每一個使用的參數，不僅僅是某一個我們認為比較重要的參數。
如果實做驗證的部份有問題，我們可以：
- 結合 [[yii\widgets\ActiveForm::enableAjaxValidation|enableClientValidation]] 和[[yii\widgets\ActiveForm::enableAjaxValidation|enableAjaxValidation]] 選項，讓多個參數可以同時透過AJAX驗證，不需要重新載入頁面。
- 從頭實做自己的驗證方式，畢竟 [[yii\validators\Validator::clientValidateAttribute]] 本來就是設計給單一參數驗證的。