php 登录时用户名与密码验证器

<?php

/**
* Validator for Login.
*/
final class LoginValidator {

private function __construct() {

}

/**
* Validate the given username and password.
* @param $username and $password to be validated
* @return array array of {@link Error} s
*/
public static function validate($username, $password) {
$errors = array();
$username = trim($username);
if (!$username) {
$errors[] = new Error('username', '用户名不能为空。');
} elseif (strlen($username)<3) {
$errors[] = new Error('username', '用户名长度不能小于3个字符。');
} elseif (strlen($username)>30) {
$errors[] = new Error('username', '用户名长度不能超过30个字符。');
} elseif (!preg_match('/^[A-Za-z]+$/',substr($username, 0, 1))) {
$errors[] = new Error('username', '用户名必须以字母开头。');
} elseif (!preg_match('/^[A-Za-z0-9_]+$/', $username)) {
$errors[] = new Error('username', '用户名只能是字母、数字以及下划线( _ )的组合。');
} elseif (!trim($password)) {
$errors[] = new Error('password', '密码不能为空。');
} else {
// check whether use exists or not
$dao = new UserDao();
$user = $dao->findByName($username);

if ($user) {
if (!($user->getPassword() == sha1($user->getSalt() . $password))) {
$errors[] = new Error('password', '用户名或密码错误。');
}
} else {
$errors[] = new Error('username', '用户名不存在。');
}
}
return $errors;
}
}

?>

<?php

/**
* Validation error.
*/
final class Error {

private $source;
private $message;

/**
* Create new error.
* @param mixed $source source of the error
* @param string $message error message
*/
function __construct($source, $message) {
$this->source = $source;
$this->message = $message;
}

/**
* Get source of the error.
* @return mixed source of the error
*/
public function getSource() {
return $this->source;
}

/**
* Get error message.
* @return string error message
*/
public function getMessage() {
return $this->message;
}

}

?>

$username = null;
$password = null;

$msg = "";

if (isset($_POST['username']) && isset($_POST['password'])) {
$username = addslashes(trim(stripslashes($_POST ['username'])));
$password = addslashes(trim(stripslashes($_POST ['password'])));
// validate
$errors = LoginValidator::validate($username, $password);

if (empty($errors)) {
// save the latest ip or login time into database, then processing page forwarding
$dao = new UserDao();
$user = $dao->findByName($username);
$last_login_ip = Utils::getIpAddress();
$user->setLastLoginIp($last_login_ip);
$now = new DateTime();
$user->setLastLoginTime($now);
$dao->save($user);
UserLogin::setUserInfo($user);
Flash::addFlash('登录成功！');
Utils::redirect('welcome');
}

foreach ($errors as $e) {
$msg .= $e->getMessage()."<br>";
}