Spring Security源码分析七：Spring Security 记住我

有这样一个场景——有个用户初访并登录了你的网站，然而第二天他又来了，却必须再次登录。于是就有了“记住我”这样的功能来方便用户使用，然而有一件不言自明的事情，那就是这种认证状态的”旷日持久“早已超出了用户原本所需要的使用范围。这意味着，他们可以关闭浏览器，然后再关闭电脑，下周或者下个月，乃至更久以后再回来，只要这间隔时间不要太离谱，该网站总会知道谁是谁，并一如既往的为他们提供所有相同的功能和服务——与许久前他们离开的时候别无二致。

记住我基本原理

1. 用户认证成功之后调用 RemeberMeService 根据用户名名生成 Token 由 TokenRepository 写入到数据库，同时也将 Token 写入到浏览器的 Cookie 中
2. 重启服务之后，用户再次登入系统会由 RememberMeAuthenticationFilter 拦截，从 Cookie 中读取 Token 信息,与 persistent_logins 表匹配判断是否使用记住我功能。最中由 UserDetailsService 查询用户信息

记住我实现

1. 创建 persistent_logins 表

create table persistent_logins (username varchar(64) not null, series varchar(64) primary key, token varchar(64) not null, last_used timestamp not null);

2. 登陆页面添加记住我复选款（name必须是remeber-me）

<input name="remember-me" type="checkbox"> 下次自动登录

3. 配置 MerryyouSecurityConfig

http.
......
                .and()
                .rememberMe()
                .tokenRepository(persistentTokenRepository())//设置操作表的Repository
                .tokenValiditySeconds(securityProperties.getRememberMeSeconds())//设置记住我的时间
                .userDetailsService(userDetailsService)//设置userDetailsService
                .and()
	......

效果如下

源码分析

首次登录

AbstractAuthenticationProcessingFilter#successfulAuthentication

protected void successfulAuthentication(HttpServletRequest request,
			HttpServletResponse response, FilterChain chain, Authentication authResult)
			throws IOException, ServletException {

		if (logger.isDebugEnabled()) {
			logger.debug("Authentication success. Updating SecurityContextHolder to contain: "
					+ authResult);
		}
		//# 1.将已认证过的Authentication放入到SecurityContext中
		SecurityContextHolder.getContext().setAuthentication(authResult);
		//# 2.登录成功调用rememberMeServices
		rememberMeServices.loginSuccess(request, response, authResult);

		// Fire event
		if (this.eventPublisher != null) {
			eventPublisher.publishEvent(new InteractiveAuthenticationSuccessEvent(
					authResult, this.getClass()));
		}

		successHandler.onAuthenticationSuccess(request, response, authResult);
	}

1. 将已认证过的Authentication放入到SecurityContext中
2. 登录成功调用rememberMeServices

AbstractRememberMeServices#loginSuccess

private String parameter = DEFAULT_PARAMETER;//remember-me

public final void loginSuccess(HttpServletRequest request,
			HttpServletResponse response, Authentication successfulAuthentication) {
		// #1.判断是否勾选记住我
		if (!rememberMeRequested(request, parameter)) {
			logger.debug("Remember-me login not requested.");
			return;
		}

		onLoginSuccess(request, response, successfulAuthentication);
	}

1. 判断是否勾选记住我

PersistentTokenBasedRememberMeServices#onLoginSuccess

protected void onLoginSuccess(HttpServletRequest request,
			HttpServletResponse response, Authentication successfulAuthentication) {
		//#1.获取用户名
		String username = successfulAuthentication.getName();

		logger.debug("Creating new persistent login for user " + username);
		//#2.创建Token
		PersistentRememberMeToken persistentToken = new PersistentRememberMeToken(
				username, generateSeriesData(), generateTokenData(), new Date());
		try {
			//#3.存储都数据库
			tokenRepository.createNewToken(persistentToken);
			//#4.写入到浏览器的Cookie中
			addCookie(persistentToken, request, response);
		}
		catch (Exception e) {
			logger.error("Failed to save persistent token ", e);
		}
	}

1. 获取用户名
2. 创建Token
3. 存储都数据库
4. 写入到浏览器的Cookie中

二次登录Remember-me

RememberMeAuthenticationFilter#doFilter

public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain)
			throws IOException, ServletException {
		HttpServletRequest request = (HttpServletRequest) req;
		HttpServletResponse response = (HttpServletResponse) res;
		//#1.判断SecurityContext中没有Authentication
		if (SecurityContextHolder.getContext().getAuthentication() == null) {
			//#2.从Cookie查询用户信息返回RememberMeAuthenticationToken
			Authentication rememberMeAuth = rememberMeServices.autoLogin(request,
					response);

			if (rememberMeAuth != null) {
				// Attempt authenticaton via AuthenticationManager
				try {
					//#3.如果不为空则由authenticationManager认证
					rememberMeAuth = authenticationManager.authenticate(rememberMeAuth);

					// Store to SecurityContextHolder
					SecurityContextHolder.getContext().setAuthentication(rememberMeAuth);

					onSuccessfulAuthentication(request, response, rememberMeAuth);
......

1. 判断SecurityContext中没有Authentication
2. 从Cookie查询用户信息返回RememberMeAuthenticationToken
3. 如果不为空则由authenticationManager认证

AbstractRememberMeServices#autoLogin

public final Authentication autoLogin(HttpServletRequest request,
			HttpServletResponse response) {
			//#1.获取Cookie
		String rememberMeCookie = extractRememberMeCookie(request);

		if (rememberMeCookie == null) {
			return null;
		}

		logger.debug("Remember-me cookie detected");

		if (rememberMeCookie.length() == 0) {
			logger.debug("Cookie was empty");
			cancelCookie(request, response);
			return null;
		}

		UserDetails user = null;

		try {
			//#2.解析Cookie
			String[] cookieTokens = decodeCookie(rememberMeCookie);
			//#3.获取用户凭证
			user = processAutoLoginCookie(cookieTokens, request, response);
			//#4.检查用户凭证
			userDetailsChecker.check(user);

			logger.debug("Remember-me cookie accepted");
			//#5.返回Authentication
			return createSuccessfulAuthentication(request, user);
		}
		catch (CookieTheftException cte) {
			cancelCookie(request, response);
			throw cte;
		}
		catch (UsernameNotFoundException noUser) {
			logger.debug("Remember-me login was valid but corresponding user not found.",
					noUser);
		}
		catch (InvalidCookieException invalidCookie) {
			logger.debug("Invalid remember-me cookie: " + invalidCookie.getMessage());
		}
		catch (AccountStatusException statusInvalid) {
			logger.debug("Invalid UserDetails: " + statusInvalid.getMessage());
		}
		catch (RememberMeAuthenticationException e) {
			logger.debug(e.getMessage());
		}

		cancelCookie(request, response);
		return null;
	}

1. 获取Cookie
2. 解析Cookie
3. 获取用户凭证
4. 检查用户凭证