controlador-descarga/models/Login.php

<?php

namespace app\models;

use Yii;
use yii\base\Model;

class Login extends Model {

  public $usuario;
  public $clave;

  private $_user = false;

  /**
   * @return array the validation rules.
   */
  public function rules() {
    return [
      [['usuario', 'clave'], 'required'],
      ['clave', '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->clave)) {
          $this->addError($attribute, 'Incorrect username or password.');
      }
    }
  }

  /**
   * Logs in a user using the provided username and password.
   * @return bool whether the user is logged in successfully
   */
  public function login() {
    if ($this->validate()) {
      return Yii::$app->user->login($this->getUser(), 3600 * 24 * 30);
    }
    return false;
  }

  /**
   * Finds user by [[username]]
   *
   * @return Usuario|null
   */
  public function getUser() {
    if ($this->_user === false) {
      $this->_user = Usuario::findByUsername($this->usuario);
    }

    return $this->_user;
  }
}