backend\models\LoginForm.php

<?php

namespace backend\models;

use Yii;
use yii\base\Model;

/**
 * Форма логина для backend
 */
class LoginForm extends Model
{
    public $username;
    public $password;
    public $rememberMe = true;

    private $_user = false;

    /**
     * @inheritdoc
     */
    public function rules()
    {
        return [
            [['username', 'password'], 'required'],
            ['rememberMe', 'boolean'],
            ['password', 'validatePassword'],
        ];
    }

    /**
     * Проверка пароля
     * This method serves as the inline validation for password.
     */
    public function validatePassword()
    {
        if (!$this->hasErrors()) {
            $user = $this->getUser();
            if (!$user || !$user->validatePassword($this->password)) {
                $this->addError('password', 'Incorrect username or password.');
            }
        }
    }

    /**
     * Аутентификация пользователя
     * @return boolean результат аутентификации
     */
    public function login()
    {
        if ($this->validate()) {
            return Yii::$app->user->login($this->getUser(), $this->rememberMe ? 3600 * 24 * 30 : 0);
        } else {
            return false;
        }
    }

    /**
     * Получение пользователя
     * @return BackendUser|null
     */
    public function getUser()
    {
        if ($this->_user === false) {
            $this->_user = BackendUser::findOne([
                'username' => $this->username,
                'is_active' => true,
            ]);
        }
        return $this->_user;
    }
}