一、前言
最近负责支付宝小程序后端项目设计，这里主要分享一下用户会话、接口鉴权的设计。参考过微信小程序后端的设计，会话需要依靠redis。相关的开发人员和我说依靠Redis并不是很靠谱，redis在业务高峰期不稳定，容易出现问题，总会出现用户会话丢失、超时的问题。之前听过JWT相关的设计，决定尝试一下。
二、什么是JWT
JSON Web Token（JWT）是一个开放标准（RFC 7519），它定义了一种紧凑且独立的方式，用于在各方之间作为JSON对象安全地传输信息。此信息可以通过数字签名进行验证和信任。JWT可以使用秘密（使用HMAC算法）或使用RSA或ECDSA的公钥/私钥对进行签名。虽然JWT可以加密以在各方之间提供保密，但我们将专注于签名令牌。签名令牌可以验证其中包含的声明的完整性，而加密令牌则隐藏其他方的声明。当使用公钥/私钥对签名令牌时，签名还证明只有持有私钥的一方是签署它的一方。
更多参考：Introduction to JSON Web Tokens
三、JWT优势
JWT支持多种方式的信息加密，验证时并不需要依赖缓存。支持存储用户非敏感信息、超时、刷新等操作，JWT由前端在用户发送请求时自动放入header中，可以有效避免CSRF攻击，用来维护服务端和用户会话再好也不过了。
四、JWT工具类
public class JwtUtils {
/**
* 创建token
*
* @param claim claim中为userId
* @param secret 创建token密钥
* @return token
*/
public static String createToken(Map claim, String secret) {
long expirationDate = AlipayServiceAppletConstants.EXPIRATION_DATE;
LocalDateTime nowTime = LocalDateTime.now();
return Jwts.builder().setClaims(claim)
.setSubject("AlipayApplet") //设置token主题
.setIssuedAt(localDateTimeToDate(nowTime)) //设置token发布时间
.setExpiration(getExpirationDate(nowTime, expirationDate)) // 设置token过期时间
.signWith(SignatureAlgorithm.HS512, secret)
.compact();
}
/**
* 将LocalDateTime转换为Date
*
* @param localDateTime
* @return Date
*/
public static Date localDateTimeToDate(LocalDateTime localDateTime) {
ZoneId zoneId = ZoneId.systemDefault();
ZonedDateTime zdt = localDateTime.atZone(zoneId);
return Date.from(zdt.toInstant());
}
/**
* 获取token过期的时间
*
* @param createTime token创建时间
* @param calendarInterval token有效时间间隔
* @return
*/
public static Date getExpirationDate(LocalDateTime createTime, long calendarInterval) {
LocalDateTime expirationDate = createTime.plus(calendarInterval, ChronoUnit.MINUTES);
return localDateTimeToDate(expirationDate);
}
/**
* JWT 解析token是否正确
*
* @param token
* @return
* @throws Exception
*/
public static Claims parseToken(String token) throws ExpiredJwtException {
Claims claims = Jwts.parser()
.setSigningKey(AlipayServiceAppletConstants.ALIPAY_APPLET_SECRET)
.parseClaimsJws(token)
.getBody();
return claims;
}
/**
* token 刷新：
* 1.小于TIME_OUT直接通过；
* 2.大于TIME_OUT 小于FORBID_REFRES_HTIME需要刷新；
* 3.超过FORBID_REFRES_HTIME 直接返回禁用刷新；
*
* @param oldToken
* @return
*/
public static String refresh(String oldToken) {
long tokenDurationTime = AlipayServiceAppletConstants.EXPIRATION_DATE;//token持续时间/分钟
long tokenRefreshDurationTime = AlipayServiceAppletConstants.ALIPAY_APPLET_FORBID_REFRES_HTIME;//token允许刷新时间/分钟
try {
getExpirationDate(oldToken);
} catch (ExpiredJwtException e) {
try {
long expirationTime = TimeUnit.MINUTES.convert(e.getClaims().getExpiration().toInstant().getEpochSecond(), TimeUnit.SECONDS);
long nowTime = TimeUnit.MINUTES.convert(Instant.now().getEpochSecond(), TimeUnit.SECONDS);
long tokenTimeout = nowTime - expirationTime;
/*2.大于TIME_OUT 小于FORBID_REFRES_HTIME需要刷新*/
if (tokenTimeout >= tokenDurationTime && tokenTimeout <= tokenRefreshDurationTime) {
return createToken(e.getClaims(), AlipayServiceAppletConstants.ALIPAY_APPLET_SECRET);
}
} catch (Exception ex) {
throw new RuntimeException("会话刷新异常...", ex);
}
}
/*3.超过FORBID_REFRES_HTIME 直接返回禁用刷新*/
throw new RuntimeException("会话不允许刷新...");
}
public static Date getExpirationDate(String token) throws ExpiredJwtException {
Claims claims = parseToken(token);
Date expiration = claims.getExpiration();
return expiration;
}
public static String resolveUserId() {
Assert.notNull(SecurityContextHolder.getContext().getAuthentication(), "授权信息不能为NULL.");
Map<String, Object> userDetail = (Map<String, Object>) SecurityContextHolder.getContext().getAuthentication().getDetails();
String userId = (String) userDetail.get("userId");
return userId;
}
}
JWT工具类主要功能：token生成、token刷新、token解析、根据token中的用户标识提取用户信息。
五、Spring Security相关知识预热
这个类定义了spring security内置的filter的优先级
final class FilterComparator implements Comparator<Filter>, Serializable {
private static final int STEP = 100;
private Map<String, Integer> filterToOrder = new HashMap<String, Integer>();
FilterComparator() {
int order = 100;
put(ChannelProcessingFilter.class, order);
order += STEP;
put(ConcurrentSessionFilter.class, order);
order += STEP;
put(WebAsyncManagerIntegrationFilter.class, order);
order += STEP;
put(SecurityContextPersistenceFilter.class, order);
order += STEP;
put(HeaderWriterFilter.class, order);
order += STEP;
put(CorsFilter.class, order);
order += STEP;
put(CsrfFilter.class, order);
order += STEP;
put(LogoutFilter.class, order);
order += STEP;
put(X509AuthenticationFilter.class, order);
order += STEP;
put(AbstractPreAuthenticatedProcessingFilter.class, order);
order += STEP;
filterToOrder.put("org.springframework.security.cas.web.CasAuthenticationFilter",
order);
order += STEP;
put(UsernamePasswordAuthenticationFilter.class, order);
order += STEP;
put(ConcurrentSessionFilter.class, order);
order += STEP;
filterToOrder.put(
"org.springframework.security.openid.OpenIDAuthenticationFilter", order);
order += STEP;
put(DefaultLoginPageGeneratingFilter.class, order);
order += STEP;
put(ConcurrentSessionFilter.class, order);
order += STEP;
put(DigestAuthenticationFilter.class, order);
order += STEP;
put(BasicAuthenticationFilter.class, order);
order += STEP;
put(RequestCacheAwareFilter.class, order);
order += STEP;
put(SecurityContextHolderAwareRequestFilter.class, order);
order += STEP;
put(JaasApiIntegrationFilter.class, order);
order += STEP;
put(RememberMeAuthenticationFilter.class, order);
order += STEP;
put(AnonymousAuthenticationFilter.class, order);
order += STEP;
put(SessionManagementFilter.class, order);
order += STEP;
put(ExceptionTranslationFilter.class, order);
order += STEP;
put(FilterSecurityInterceptor.class, order);
order += STEP;
put(SwitchUserFilter.class, order);
}
//......
}
Spring Security 的permitAll以及webIgnore的区别
- web ignore比较适合配置前端相关的静态资源，它是完全绕过spring security的所有filter的；
- 而permitAll，会给没有登录的用户适配一个AnonymousAuthenticationToken，设置到SecurityContextHolder，方便后面的filter可以统一处理authentication。
- 参考链接：https://segmentfault.com/a/1190000012160850
Spring Security Authentication （认证）原理
- AuthenticationManager通过委托AuthenticationProvider来实现认证；
- AuthenticationProvider会调用UserDetailsService拿到UserDetails对象并封装最终的 Authentication 对象放到SecurityContextHolder中；
- SecurityContextHolder 是 Spring Security 最基础的对象，用于存储应用程序当前安全上下文的详细信息，这些信息后续会被用于授权；
参考链接：https://www.jianshu.com/p/e8e0e366184e
六、SpringSecurity基本配置
@Configuration
public class AlipayAppletSecurityConfig extends WebSecurityConfigurerAdapter { @Override
public void configure(WebSecurity web) {
web.ignoring().antMatchers("/alipay-applet/login");
web.ignoring().antMatchers("/alipay-applet/ag");
web.ignoring().regexMatchers("^(?!(/alipay-applet)).*$");
} @Override
protected void configure(AuthenticationManagerBuilder auth) {
auth.authenticationProvider(new TokenAuthenticationProvider(new SecurityProviderManager()));
} @Override
protected void configure(HttpSecurity http) throws Exception {
//禁用缓存
http.headers().cacheControl();
http.csrf().disable()
.authorizeRequests()
.antMatchers("/alipay-applet/**").authenticated()
.and()
.formLogin().disable() //不要UsernamePasswordAuthenticationFilter
.httpBasic().disable() //不要BasicAuthenticationFilter
.sessionManagement().sessionCreationPolicy(SessionCreationPolicy.STATELESS).and()
.securityContext().and()
.anonymous().disable()
.servletApi(); AuthenticationManager authenticationManager = authenticationManager();
TokenAuthenticationFilter filter = new TokenAuthenticationFilter(authenticationManager);
http.addFilterBefore(filter, UsernamePasswordAuthenticationFilter.class);
} @Bean
public CorsFilter corsFilter() {
//1.添加CORS配置信息
CorsConfiguration config = new CorsConfiguration();
//放行哪些原始域
config.addAllowedOrigin("*");
//是否发送Cookie信息
config.setAllowCredentials(true);
//放行哪些原始域(请求方式)
config.addAllowedMethod("*");
//放行哪些原始域(头部信息)
config.addAllowedHeader("*");
//暴漏刷新token的header
config.addExposedHeader(AlipayAppletSecurityConstants.RFRESH_TOKEN_HEADER_NAME);
//2.添加映射路径
UrlBasedCorsConfigurationSource configSource = new UrlBasedCorsConfigurationSource();
configSource.registerCorsConfiguration("/alipay-applet/**", config); //3.返回新的CorsFilter.
return new CorsFilter(configSource);
}
}
- web ignore配置：忽略非支付宝后端服务的请求、忽略用户登录的请求、忽略支付宝回调请求；
- 添加自定义AuthenticationProvider；
- 禁用缓存、不启用CSRF配置（因为是基于token认证，不用担心csrf攻击）、去掉UsernamePasswordAuthenticationFilter和BasicAuthenticationFilter、session策略为STATELESS、禁止匿名访问；
- CORS设置（针对支付宝小程序后端服务），暴露指定的response header；
- 添加自定义AuthenticationFilter
七、自定义AuthenticationFilter
class TokenAuthenticationFilter extends OncePerRequestFilter {
private static Logger LOGGER = LoggerFactory.getLogger(TokenAuthenticationFilter.class);
private final AuthenticationManager authenticationManager;
public TokenAuthenticationFilter(AuthenticationManager authenticationManager) {
this.authenticationManager = authenticationManager;
}
@Override
protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response,
FilterChain filterChain) throws ServletException {
try {
if (SecurityContextHolder.getContext().getAuthentication() != null) {
filterChain.doFilter(request, response);
//已经完成认证
return;
}
StatelessTokenAuthentication authentication = new StatelessTokenAuthentication(request, response);
Authentication authResult = authenticationManager.authenticate(authentication);
Assert.isTrue(authResult.isAuthenticated(), "Token is not authenticated!");
SecurityContextHolder.getContext().setAuthentication(authResult);
filterChain.doFilter(request, response);
} catch (Exception e) {
LOGGER.error("TokenAuthenticationFilter异常...", e);
try {
WmhcomplexmsgcenterErrorHandler.handleCore(request, response, e);
} catch (ServiceException ex) {
throw new ServletException(ex);
}
}
}
}
- 通过SecurityContextHolder.getContext().getAuthentication() != null来判断当前请求是否已经被认证；
- 构造需要认证的StatelessTokenAuthentication用户凭证信息；
- 通过AuthenticationManager 验证用户凭证并
- 返回认证后StatelessTokenAuthentication信息，并绑定到SecurityContextHolder中；
八、自定义AuthenticationProvider
class TokenAuthenticationProvider implements AuthenticationProvider {
private final SecurityProviderManager providerManager;
public TokenAuthenticationProvider(SecurityProviderManager providerManager) {
this.providerManager = providerManager;
}
@Override
public Authentication authenticate(Authentication authentication) throws AuthenticationException {
StatelessTokenAuthentication tokenAuth = (StatelessTokenAuthentication) authentication;
StatelessTokenAuthentication.Credentials credentials = (StatelessTokenAuthentication.Credentials) tokenAuth.getCredentials();
//查找Token
HttpServletRequest request = credentials.getRequest();
try {
return providerManager.parseToken(request);
} catch (ExpiredJwtException e) {
HttpServletResponse response = credentials.getResponse();
try {
return providerManager.tryRefreshAndParseToken(request, response);
} catch (Exception ex) {
throw new InternalAuthenticationServiceException("重新鉴权出错，请重新登陆...", ex);
}
} catch (Exception e) {
throw new InternalAuthenticationServiceException("鉴权出错，请重新登陆...", e);
}
}
@Override
public boolean supports(Class<?> authentication) {
return ClassUtils.isAssignable(StatelessTokenAuthentication.class, authentication);
}
}
- 验证StatelessTokenAuthentication信息【解析JWT】；
- JWT过期，在一定时间范围内，自动刷新JWT并写入response header中；
class SecurityProviderManager {
private static Logger LOGGER = LoggerFactory.getLogger(SecurityProviderManager.class);
private static final String DEFAULT_TOKEN = "ALIPAY#APPLET_DEFAULT#TOKEN[1qa2ws3ed!@#$%^]";
private String resolveToken(HttpServletRequest request) {
String token = request.getHeader(AlipayAppletSecurityConstants.TOKEN_HEADER_NAME);
if (StringUtils.isBlank(token)) {
throw new TokenNotFoundException("找不到Token, header name is " + AlipayAppletSecurityConstants.TOKEN_HEADER_NAME);
}
return token;
}
public Authentication parseToken(HttpServletRequest request) {
String token = this.resolveToken(request);
Object userDetail;
try {
if (!(token.startsWith(DEFAULT_TOKEN) && (userDetail = parseDefaultToken(token)) != null)) {
userDetail = JwtUtils.parseToken(token);
}
} catch (ExpiredJwtException e) {
throw e;
} catch (Exception e) {
throw new IllegalStateException(String.format("token解析异常..., token=%s", token), e);
}
if (null == userDetail) {
throw new IllegalStateException("用户对象不能为null! token=" + token);
}
return new StatelessTokenAuthentication(userDetail);
}
public Authentication tryRefreshAndParseToken(HttpServletRequest request, HttpServletResponse response) {
String token = this.resolveToken(request);
String refreshToken;
try {
refreshToken = JwtUtils.refresh(token);
} catch (Exception e) {
throw new IllegalStateException("token刷新异常... token=" + token, e);
}
Object userDetail;
try {
userDetail = JwtUtils.parseToken(refreshToken);
} catch (Exception e) {
throw new IllegalStateException("token解析异常..., refresh_token=" + refreshToken, e);
}
if (null == userDetail) {
throw new IllegalStateException("用户对象不能为null! refresh_token=" + refreshToken);
}
response.addHeader(AlipayAppletSecurityConstants.RFRESH_TOKEN_HEADER_NAME, refreshToken);
return new StatelessTokenAuthentication(userDetail);
}
private static Object parseDefaultToken(String token) {
String[] session = token.split(":");
if (session.length == 2) {
LOGGER.info("alipay applet default token info is " + token);
return new HashMap<String, Object>() {
{
put("userId", session[1]);
}
};
} else {
LOGGER.error(String.format("alipay applet default token= %s 不合法", token));
}
return null;
}
}
- 解析JWT，获取用户信息；
- 刷新JWT，通知前端，保证会话不会断开；
- 默认Token侧率，避免测试接口不必要的麻烦；
九、测试结果
十、总结
这一次后端鉴权模块的设计也是属于自己的一次突破吧，前后端的联调没有出现太大的岔子。最终顺利的上线了！！！另外分享一下在阅读spring security源码时的收获：AutowireBeanFactoryObjectPostProcessor。对，没错，就是这个对象后置处理器。如果你阅读了spring security的源码，你会发现很多对象，比如WebSecurity、ProviderManager、各个安全Filter等，这些对象的创建并不是通过bean定义的形式被容器发现和注册进入spring容器的，而是直接new出来的。AutowireBeanFactoryObjectPostProcessor这个工具类可以使这些对象具有容器bean同样的生命周期，也能注入相应的依赖，从而进入准备好被使用的状态。参考Spring Security Config 5.1.2 源码解析 -- 工具类 AutowireBeanFactoryObjectPostProcessor。