backend/models/LoginForm.php

<?php
    namespace backend\models;
    
    use common\models\User;
    use Yii;
    use yii\base\Model;
    
    /**
     * Login form
     */
    class LoginForm extends Model
    {
        public $username;
        public $password;
        public $rememberMe = true;
        
        private $user;
        
        /**
         * @inheritdoc
         */
        public function rules()
        {
            return [
                // username and password are both required
                [
                    [
                        'username',
                        'password',
                    ],
                    'required',
                ],
                // rememberMe must be a boolean value
                [
                    'rememberMe',
                    'boolean',
                ],
                // password is validated by validatePassword()
                [
                    'password',
                    'validatePassword',
                ],
            ];
        }
        
        /**
         * Validates the password.
         * This method serves as the inline validation for password.
         *
         * @param string $attribute the attribute currently being validated
         * @param array  $params    the additional name-value pairs given in the rule
         */
        public function validatePassword($attribute, $params)
        {
            if (!$this->hasErrors()) {
                $user = $this->getUser();
                if (!$user || !$user->validatePassword($this->password)) {
                    $this->addError($attribute, 'Incorrect username or password.');
                }
            }
        }
        
        /**
         * Logs in a user using the provided username and password.
         *
         * @return boolean whether the user is logged in successfully
         */
        public function login()
        {
            if ($this->validate()) {
                return Yii::$app->user->login($this->getUser(), $this->rememberMe ? 3600 * 24 * 30 : 0);
            } else {
                return false;
            }
        }
        
        /**
         * Finds user by [[username]]
         *
         * @return User|null
         */
        protected function getUser()
        {
            if ($this->user === null) {
                $this->user = User::findByUsername($this->username);
            }
            return $this->user;
        }
        
        /**
         * @inheritdoc
         */
        public function attributeLabels()
        {
            return [
                'username' => 'Имя пользователя',
                'password' => 'Пароль',
                'rememberMe' => 'Запомнить пароль',
            ];
        }
    }