Yii2 Ajax Validation and unique rules in active record

Yii2  Ajax Validation and unique rules in activeForm Field

View Page

frontend/views/site/signup.php

<?php

use yii\helpers\Html;
use yii\bootstrap\ActiveForm;

$this->title = 'Signup';
$this->params['breadcrumbs'][] = $this->title;
?>
    <div class="site-signup">
        <h1><?= Html::encode($this->title) ?></h1>

        <p>Please fill out the following fields to signup:</p>

        <div class="row">
            <div class="col-lg-5">
                <?php $form = ActiveForm::begin([
'id' => $model->formname(),
enableAjaxValidation'=>true,
]); ?>

                    <?= $form->field($model, 'username')->textInput(['autofocus' => true]) ?>

                        <?= $form->field($model, 'email') ?>

                            <?= $form->field($model, 'password')->passwordInput() ?>

                                <div class="form-group">
                                    <?= Html::submitButton('Signup', ['class' => 'btn btn-primary', 'name' => 'signup-button']) ?>
                                </div>

                                <?php ActiveForm::end(); ?>
            </div>
        </div>
    </div>

Model

frontend/models/SignupForm.php


< ?php
namespace frontend\ models;

use yii\ base\ Model;
use common\ models\ User;

/**
 * Signup form
 */
class SignupForm extends Model {
    public $username;
    public $email;
    public $password;

    /**
     * @inheritdoc
     */
    public
    function rules() {
        return [
            ['username', 'trim'],
            ['username', 'required'],
            ['username', 'unique', 'targetClass' => '\common\models\User', 'message' => 'This username has already been taken.'],
            ['username', 'string', 'min' => 2, 'max' => 255],

            ['email', 'trim'],
            ['email', 'required'],
            ['email', 'email'],
            ['email', 'string', 'max' => 255],
            ['email', 'unique', 'targetClass' => '\common\models\User', 'message' => 'This email address has already been taken.'],

            ['password', 'required'],
            ['password', 'string', 'min' => 6],
        ];
    }

    /**
     * Signs user up.
     *
     * @return User|null the saved model or null if saving fails
     */
    public
    function signup() {
        if (!$this - > validate()) {
            return null;
        }

        $user = new User();
        $user - > username = $this - > username;
        $user - > email = $this - > email;
        $user - > setPassword($this - > password);
        $user - > generateAuthKey();

        return $user - > save() ? $user : null;
    }
}

Controller

frontend/controllers/SiteController.php

<?php
namespace frontend\controllers;

use Yii;
use yii\base\InvalidParamException;
use yii\web\BadRequestHttpException;
use yii\web\Controller;
use yii\filters\VerbFilter;
use yii\filters\AccessControl;
use frontend\models\SignupForm;
use yii\helpers\Json;
use yii\widgets\ActiveForm;

class SiteController extends Controller
{

    public function behaviors()
    {
        return [
            'access' => [
                'class' => AccessControl::className(),
                'only' => ['logout', 'signup'],
                'rules' => [
                    [
                        'actions' => ['signup'],
                        'allow' => true,
                        'roles' => ['?'],
                    ],
                    [
                        'actions' => ['logout'],
                        'allow' => true,
                        'roles' => ['@'],
                    ],
                ],
            ],
            'verbs' => [
                'class' => VerbFilter::className(),
                'actions' => [
                    'logout' => ['post'],
                ],
            ],
        ];
    }

    public function actions()
    {
        return [
            'error' => [
                'class' => 'yii\web\ErrorAction',
            ],
            'captcha' => [
                'class' => 'yii\captcha\CaptchaAction',
                'fixedVerifyCode' => YII_ENV_TEST ? 'testme' : null,
            ],
        ];
    }

    public function actionSignup()
    {
        $model = new SignupForm();

if(Yii::$app->request->isAjax && $model->load(Yii::$app->request->post()))
{
Yii::$app->response->format = 'json';
return ActiveForm::validate($model);
}


        if ($model->load(Yii::$app->request->post())) {
            if ($user = $model->signup()) {
                if (Yii::$app->getUser()->login($user)) {
                    return $this->goHome();
                }
            }
        }

        return $this->render('signup', [
            'model' => $model,
        ]);
    }
}

Yii2  Ajax Validation and unique rules in active record