Ajax validation in Yii2. Why is a validation error not displayed for the uniqueness of the field?

Question

Yii

Hello, I'm new to Yii2 and programming too. I am making a registration form, I need to check for the uniqueness of the email without reloading the page, I do this: view:

<?php $form = ActiveForm::begin(['id' => 'registration-form', 'enableAjaxValidation' => true]); ?>
    <div class="form-group">
        <label for="email-pop-up">E-mail</label> 
        <?= $form->field($model_reg, 'email')->textInput()->label(false);  ?>
    </div>
    <div class="form-group">
        <label for="password-pop-up-1">Пароль</label> 
        <?= yii\helpers\Html::activePasswordInput($model_reg, 'password', ['class' => 'form-control']); ?>
    </div>
    <div class="form-group">
        <label for="password-pop-up-2">Повторить пароль</label>  
        <?= yii\helpers\Html::activePasswordInput($model_reg, 'password_repeat', ['class' => 'form-control']); ?>
    </div>

Rules in the model:

public function rules(){
    return [
        [['email',  'password', 'password_repeat'],'required'],
        ['email', 'email'],
        ['email', 'unique', 'targetClass'=>'app\models\Person'], 
        ['password', 'compare', 'compareAttribute' => 'password_repeat'],

    ];
}

Controller:

$model_reg = new \app\models\Predreg();

    if (Yii::$app->request->isAjax && $model_reg->load(Yii::$app->request->post('Predreg'))) {
        Yii::$app->response->format = Response::FORMAT_JSON;    
        return ActiveForm::validate($model_reg);
        Yii::$app->end();
    } 

    if (Yii::$app->request->post('Predreg')) {
        $model_reg->attributes = Yii::$app->request->post('Predreg');
        if ($model_reg->validate()){
            if ($model_reg->predreg()){

               return \yii\helpers\Url::home();

            } 
        }
    }

The error related to passwords works correctly, but the error of the non-unique email address is not displayed, if I remove the property from the 'enableAjaxValidation' form, then after reloading the page the error is in place. How can I get this error without reloading the page??

Answer 1

On the yiiframework.ru forum, they suggested that in order for the error to be displayed, you need to add validationUrl to the form

<?php $form = ActiveForm::begin([
      'id' => 'registration-form',
      'enableAjaxValidation' => true,
      'validationUrl' => \yii\helpers\Url::to(['validate-form']), // Добавить URL валидации
    ]); ?>

and in the controller add

public function actionValidateForm() 
    {
        if (Yii::$app->request->isAjax) {
            Yii::$app->response->format = \yii\web\Response::FORMAT_JSON;

            $model = new \app\models\Predreg();
            if($model->load(Yii::$app->request->post()))
                return \yii\widgets\ActiveForm::validate($model);
        }
        throw new \yii\web\BadRequestHttpException('Bad request!');
    }