À propos de l'implémentation de la fonction de connexion dans le framework Yii de PHP

public function authenticate() 
{ 
  $users=array( 
    // username => password 
    'demo'=>'demo', 
    'admin'=>'admin', 
  ); 
  if(!isset($users[$this->username])) 
    $this->errorCode=self::ERROR_USERNAME_INVALID; 
  elseif($users[$this->username]!==$this->password) 
    $this->errorCode=self::ERROR_PASSWORD_INVALID; 
  else 
    $this->errorCode=self::ERROR_NONE; 
  return !$this->errorCode; 
}

/** 
 * Authenticates the password. 
 * This is the 'authenticate' validator as declared in rules(). 
 */ 
public function authenticate($attribute,$params) 
{ 
  $this->_identity=new UserIdentity($this->username,$this->password); 
  if(!$this->_identity->authenticate()) 
    $this->addError('password','用户名或密码错误'); 
} 
 
/** 
 * Logs in the user using the given username and password in the model. 
 * @return boolean whether login is successful 
 */ 
public function login() 
{ 
  if($this->_identity===null) 
  { 
    $this->_identity=new UserIdentity($this->username,$this->password); 
    $this->_identity->authenticate(); 
  } 
  if($this->_identity->errorCode===UserIdentity::ERROR_NONE) 
  { 
    $duration=$this->rememberMe ? 3600*24*30 : 0; // 30 days 
    Yii::app()->user->login($this->_identity,$duration); 
    return true; 
  } 
  else 
    return false; 
}

/** 
 * Displays the login page 
 */ 
public function actionLogin() 
{ 
  if (!defined('CRYPT_BLOWFISH')||!CRYPT_BLOWFISH) 
    throw new CHttpException(500,"This application requires that PHP was compiled with Blowfish support for crypt()."); 
 
  $model=new LoginForm; 
 
  // if it is ajax validation request 
  if(isset($_POST['ajax']) && $_POST['ajax']==='login-form') 
  { 
    echo CActiveForm::validate($model); 
    Yii::app()->end(); 
  } 
 
  // collect user input data 
  if(isset($_POST['LoginForm'])) 
  { 
    $model->attributes=$_POST['LoginForm']; 
    // validate user input and redirect to the previous page if valid 
    if($model->validate() && $model->login()) 
      $this->redirect(Yii::app()->user->returnUrl); 
  } 
  // display the login form 
  $this->render('login',array('model'=>$model)); 
}

drop table if exists `admin`; 
create table `admin` ( 
  `admin_id` int unsigned not null auto_increment comment '主键', 
  `username` varchar(32) not null comment '登录名', 
  `psw` char(40) not null comment '登录密码（两次sha1）', 
  `nick` varchar(64) not null comment '昵称', 
  `add_time` datetime not null comment '创建时间', 
  `login_time` datetime null comment '最近登录时间', 
  unique key(`username`), 
  primary key (`admin_id`) 
) engine=innodb default charset=utf8 comment='管理员表';

public function authenticate() 
{ 
  if(strlen($this->password) > 0) 
    $this->password = sha1(sha1($this->password)); 
  $user = Admin::model()->findByAttributes(array('username' => $this->username)); 
  if($user == null) 
    $this->errorCode=self::ERROR_USERNAME_INVALID; 
  elseif( !($user instanceof Admin) || ($user->psw != $this->password) ) 
    $this->errorCode=self::ERROR_PASSWORD_INVALID; 
  else 
  { 
    $this->setState('admin_id', $user->admin_id); 
    $this->setState('nick', $user->nick); 
    $this->setState('username', $user->username); 
    $user->login_time = date('Y-m-d H:i:s'); 
    $user->save(); 
    $this->errorCode=self::ERROR_NONE; 
  } 
  return !$this->errorCode; 
}

    'user' => [
      'identityClass' => 'app\models\User',
      'enableAutoLogin' => true,
    ],

  public function login($identity, $duration = 0)
  {
    if ($this->beforeLogin($identity, false, $duration)) {
      $this->switchIdentity($identity, $duration);
      $id = $identity->getId();
      $ip = Yii::$app->getRequest()->getUserIP();
      Yii::info("User '$id' logged in from $ip with duration $duration.", __METHOD__);
      $this->afterLogin($identity, false, $duration);
    }

    return !$this->getIsGuest();
  }

  public function switchIdentity($identity, $duration = 0)
  {
    $session = Yii::$app->getSession();
    if (!YII_ENV_TEST) {
      $session->regenerateID(true);
    }
    $this->setIdentity($identity);
    $session->remove($this->idParam);
    $session->remove($this->authTimeoutParam);
    if ($identity instanceof IdentityInterface) {
      $session->set($this->idParam, $identity->getId());
      if ($this->authTimeout !== null) {
        $session->set($this->authTimeoutParam, time() + $this->authTimeout);
      }
      if ($duration > 0 && $this->enableAutoLogin) {
        $this->sendIdentityCookie($identity, $duration);
      }
    } elseif ($this->enableAutoLogin) {
      Yii::$app->getResponse()->getCookies()->remove(new Cookie($this->identityCookie));
    }
  }

  protected function sendIdentityCookie($identity, $duration)
  {
    $cookie = new Cookie($this->identityCookie);
    $cookie->value = json_encode([
      $identity->getId(),
      $identity->getAuthKey(),
      $duration,
    ]);
    $cookie->expire = time() + $duration;
    Yii::$app->getResponse()->getCookies()->add($cookie);
  }

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

 public function getIsGuest($checkSession = true)
  {
    return $this->getIdentity($checkSession) === null;
  }
  public function getIdentity($checkSession = true)
  {
    if ($this->_identity === false) {
      if ($checkSession) {
        $this->renewAuthStatus();
      } else {
        return null;
      }
    }

    return $this->_identity;
  }

 protected function renewAuthStatus()
  {
    $session = Yii::$app->getSession();
    $id = $session->getHasSessionId() || $session->getIsActive() ? $session->get($this->idParam) : null;

    if ($id === null) {
      $identity = null;
    } else {
      /** @var IdentityInterface $class */
      $class = $this->identityClass;
      $identity = $class::findIdentity($id);
    }

    $this->setIdentity($identity);

    if ($this->authTimeout !== null && $identity !== null) {
      $expire = $session->get($this->authTimeoutParam);
      if ($expire !== null && $expire < time()) {
        $this->logout(false);
      } else {
        $session->set($this->authTimeoutParam, time() + $this->authTimeout);
      }
    }

    if ($this->enableAutoLogin) {
      if ($this->getIsGuest()) {
        $this->loginByCookie();
      } elseif ($this->autoRenewCookie) {
        $this->renewIdentityCookie();
      }
    }
  }

 protected function loginByCookie()
  {
    $name = $this->identityCookie['name'];
    $value = Yii::$app->getRequest()->getCookies()->getValue($name);
    if ($value !== null) {
      $data = json_decode($value, true);
      if (count($data) === 3 && isset($data[0], $data[1], $data[2])) {
        list ($id, $authKey, $duration) = $data;
        /** @var IdentityInterface $class */
        $class = $this->identityClass;
        $identity = $class::findIdentity($id);
        if ($identity !== null && $identity->validateAuthKey($authKey)) {
          if ($this->beforeLogin($identity, true, $duration)) {
            $this->switchIdentity($identity, $this->autoRenewCookie ? $duration : 0);
            $ip = Yii::$app->getRequest()->getUserIP();
            Yii::info("User '$id' logged in from $ip via cookie.", __METHOD__);
            $this->afterLogin($identity, true, $duration);
          }
        } elseif ($identity !== null) {
          Yii::warning("Invalid auth key attempted for user '$id': $authKey", __METHOD__);
        }
      }
    }
  }

 $this->switchIdentity($identity, $this->autoRenewCookie ? $duration : 0);

 public function logout($destroySession = true)
  {
    $identity = $this->getIdentity();
    if ($identity !== null && $this->beforeLogout($identity)) {
      $this->switchIdentity(null);
      $id = $identity->getId();
      $ip = Yii::$app->getRequest()->getUserIP();
      Yii::info("User '$id' logged out from $ip.", __METHOD__);
      if ($destroySession) {
        Yii::$app->getSession()->destroy();
      }
      $this->afterLogout($identity);
    }

    return $this->getIsGuest();
  }


  public function switchIdentity($identity, $duration = 0)
  {
    $session = Yii::$app->getSession();
    if (!YII_ENV_TEST) {
      $session->regenerateID(true);
    }
    $this->setIdentity($identity);
    $session->remove($this->idParam);
    $session->remove($this->authTimeoutParam);
    if ($identity instanceof IdentityInterface) {
      $session->set($this->idParam, $identity->getId());
      if ($this->authTimeout !== null) {
        $session->set($this->authTimeoutParam, time() + $this->authTimeout);
      }
      if ($duration > 0 && $this->enableAutoLogin) {
        $this->sendIdentityCookie($identity, $duration);
      }
    } elseif ($this->enableAutoLogin) {
      Yii::$app->getResponse()->getCookies()->remove(new Cookie($this->identityCookie));
    }
  }