S2OJ/web/app/models/Auth.php

<?php

class Auth {
	public static function check() {
		global $myUser;

		return $myUser !== null;
	}

	public static function id() {
		global $myUser;

		if ($myUser === null) {
			return null;
		}

		return $myUser['username'];
	}

	public static function user() {
		global $myUser;

		return $myUser;
	}

	public static function property($name) {
		global $myUser;

		if (!$myUser) {
			return false;
		}

		return $myUser[$name];
	}

	public static function login($username) {
		if (!validateUsername($username)) {
			return;
		}

		$_SESSION['username'] = $username;

		$remember_token = DB::selectSingle([
			"select remember_token from user_info",
			"where", ["username" => $username]
		]);

		if ($remember_token == '') {
			$remember_token = uojRandString(60);
			DB::update([
				"update user_info",
				"set", ["remember_token" => $remember_token],
				"where", ["username" => $username]
			]);
		}

		$_SESSION['last_login'] = time();
		$_SESSION['remember_token'] = $remember_token;

		$expire = time() + 60 * 60 * 24 * 7;
		Cookie::safeSet('uoj_username', $username, $expire, '/', array('httponly' => true));
		Cookie::safeSet('uoj_remember_token', $remember_token, $expire, '/', array('httponly' => true));

		DB::update([
			"update user_info",
			"set", ["last_login_time" => UOJTime::$time_now_str],
			"where", ["username" => $username]
		]);

		session_regenerate_id(true);
	}

	public static function logout() {
		session_unset();

		Cookie::unsetVar(session_name(), '/');
		Cookie::safeUnset('uoj_username', '/');
		Cookie::safeUnset('uoj_remember_token', '/');

		DB::update([
			"update user_info",
			"set", ["remember_token" => ''],
			"where", ["username" => Auth::id()]
		]);
	}

	private static function initMyUser() {
		global $myUser;
		$myUser = null;

		Cookie::safeCheck('uoj_username', '/');
		Cookie::safeCheck('uoj_remember_token', '/');

		if (isset($_SESSION['username'])) {
			if (!validateUsername($_SESSION['username'])) {
				return;
			}

			$myUser = UOJUser::query($_SESSION['username']);

			// 当 remember_token 不同时，注销登录
			if ($_SESSION['remember_token'] !== $myUser['remember_token']) {
				$myUser = null;
				return;
			}

			return;
		}

		$remember_token = Cookie::safeGet('uoj_remember_token', '/');
		if ($remember_token != null) {
			$username = Cookie::safeGet('uoj_username', '/');

			if (!validateUsername($username)) {
				return;
			}

			$myUser = UOJUser::query($username);

			if ($myUser['remember_token'] !== $remember_token) {
				$myUser = null;
				return;
			}

			$_SESSION['username'] = $myUser['username'];
			$_SESSION['remember_token'] = $myUser['remember_token'];

			return;
		}
	}

	public static function init() {
		global $myUser;

		Auth::initMyUser();
		if ($myUser && UOJUser::getAccountStatus($myUser) != 'ok') {
			$myUser = null;
		}

		if ($myUser) {
			if (!isset($_SESSION['last_login'])) {
				$_SESSION['last_login'] = strtotime($myUser['last_login_time']);
			}

			$myUser = UOJUser::updateVisitHistory($myUser, [
				'remote_addr' => UOJContext::remoteAddr(),
				'http_x_forwarded_for' => UOJContext::httpXForwardedFor(),
				'http_user_agent' => UOJContext::httpUserAgent()
			]);

			$_SESSION['last_visited'] = time();
		}
	}
}