概述
与Spring、Spring MVC、Spring Boot一样,Spring Security里也有很多Handler接口、可以分为两大类,一类是普通的XxxHandler
(见名知意),另一类是对应的ServerXxxHandler
(RequestRejectedHandler除外)。
以AuthenticationSuccessHandler为例,Spring Security中用于处理认证成功事件的接口。通常与基于Servlet API的应用程序一起使用,如Spring MVC应用程序。当用户成功认证后,接口的实现类负责处理接下来的操作,如重定向到其他页面、生成认证成功的日志等。主要实现类是SavedRequestAwareAuthenticationSuccessHandler,它会将用户重定向到之前被拦截的原始请求地址。
而对应的ServerAuthenticationSuccessHandler,在Spring Security 5引入的新接口,用于处理WebFlux中的认证成功事件。WebFlux是Spring Framework 5中引入的反应式编程模型,用于构建响应式的、非阻塞的、事件驱动的应用程序。该接口的实现类负责发送响应给客户端,例如返回 JSON 格式的认证成功消息。
Spring Security里定义的Handler接口具体如下:
- AuthenticationSuccessHandler
- AuthenticationFailureHandler
- LogoutHandler
- LogoutSuccessHandler
- AccessDeniedHandler
- CsrfTokenRequestHandler
- RequestRejectedHandler
- ServerAuthenticationSuccessHandler
- ServerAuthenticationFailureHandler
- ServerLogoutHandler
- ServerLogoutSuccessHandler
- ServerAccessDeniedHandler
- ServerCsrfTokenRequestHandler
AuthenticationSuccessHandler
AuthenticationSuccessHandler接口用来设置验证成功后的处理动作,源码如下:
public interface AuthenticationSuccessHandler {
default void onAuthenticationSuccess(HttpServletRequest request, HttpServletResponse response, FilterChain chain, Authentication authentication) throws IOException, ServletException {
this.onAuthenticationSuccess(request, response, authentication);
chain.doFilter(request, response);
}
void onAuthenticationSuccess(HttpServletRequest request, HttpServletResponse response, Authentication authentication) throws IOException, ServletException;
}
有两个同名onAuthenticationSuccess方法:default方法,用于处理特定的认证请求AuthenticationFilter;非default方法,则用来处理登录成功的具体事项。目前有3个实现类:
- ForwardAuthenticationSuccessHandler:实现服务端跳转
- SimpleUrlAuthenticationSuccessHandler:同时继承AbstractAuthenticationTargetUrlRequestHandler,通过其中的handle方法实现请求重定向
- SavedRequestAwareAuthenticationSuccessHandler:继承自SimpleUrlAuthenticationSuccessHandler,在其基础上增加请求缓存的功能,可以记录之前请求的地址,进而在登录成功后重定向到一开始访问的地址。
开发者也可以配置自己的SavedRequestAwareAuthenticationSuccessHandler,方法如下:
SavedRequestAwareAuthenticationSuccessHandler successHandler() {
SavedRequestAwareAuthenticationSuccessHandler handler = new SavedRequestAwareAuthenticationSuccessHandler;
handler.setDefaultTargetUrl("/index");
handler.setTargetUrlParameter("target");
return handler;
}
ForwardAuthenticationSuccessHandler的onAuthenticationSuccess方法就一行:request.getRequestDispatcher(this.forwardUrl).forward(request, response);
,即调用getRequestDispatcher方法进行服务端转发
AuthenticationFailureHandler
AuthenticationFailureHandler接口,用来设置用户验证失败后的处理动作,源码如下:
public interface AuthenticationFailureHandler {
void onAuthenticationFailure(HttpServletRequest request, HttpServletResponse response, AuthenticationException exception) throws IOException, ServletException;
}
实现类有:
- SimpleUrlAuthenticationFailureHandler:默认,如果指定failureUrl,则跳转到该URL,未指定则返回401错误代码。也可以通过配置forwardToDestination属性将重定向改为服务器端跳转
- ForwardAuthenticationFailureHandler:不管报哪种AuthenticationException,总是重定向到指定的URL
- DelegatingAuthenticationFailureHandler:代理类,可根据不同的AuthenticationException类型,设置不同的Handlers
- ExceptionMappingAuthenticationFailureHandler:可以根据不同的AuthenticationException类型,设置不同的跳转URL
- AuthenticationEntryPointFailureHandler:可通过AuthenticationEntryPoint来处理登录异常
类继承图
DelegatingAuthenticationFailureHandler处理方法handle如下:
// 维护一个map,key是具体的异常类型,value是特定的Handler
private final LinkedHashMap<Class<? extends AuthenticationException>, AuthenticationFailureHandler> handlers;
public void onAuthenticationFailure(HttpServletRequest request, HttpServletResponse response, AuthenticationException exception) throws IOException, ServletException {
for (Map.Entry<Class<? extends AuthenticationException>, AuthenticationFailureHandler> entry : this.handlers.entrySet()) {
Class<? extends AuthenticationException> handlerMappedExceptionClass = entry.getKey();
if (handlerMappedExceptionClass.isAssignableFrom(exception.getClass())) {
AuthenticationFailureHandler handler = entry.getValue();
handler.onAuthenticationFailure(request, response, exception);
return;
}
}
this.defaultHandler.onAuthenticationFailure(request, response, exception);
}
值得注意的是,Delegating,代理的意思。此实现类里维护一个Map(此Map集合支持通过构造函数的入参这种方式来实例化Handler类),然后在核心方法里对Map里的key进行遍历,与方法入参里的exception对比,比对成功则加以处理。最后使用默认的Handler加以处理。这种思想,在下面的几个Handler里,几乎都是如此。不同的是Map的key不一样,核心方法名不一样(一般都命名为handle()
),对比项不一样(有的是对比request)。不再赘述。
LogoutHandler
LogoutHandler接口,设置logout过程中必须处理动作,logout后的重定向建议使用LogoutSuccessHandler,源码如下:
public interface LogoutHandler {
void logout(HttpServletRequest request, HttpServletResponse response, Authentication authentication);
}
有如下几个实现类:
- AbstractRememberMeServices:
- CompositeLogoutHandler:
- CookieClearingLogoutHandler:清除Cookie
- CsrfLogoutHandler:通过CsrfTokenRepository清除CsrfToken
- HeaderWriterLogoutHandler:
- LogoutSuccessEventPublishingLogoutHandler:同时实现ApplicationEventPublisherAware,发布一个事件通知
- OidcBackChannelLogoutHandler:
- PersistentTokenBasedRememberMeServices
- SecurityContextLogoutHandler
- SpringSessionRememberMeServices
- TokenBasedRememberMeServices
CompositeLogoutHandler接口源码如下:
private final List<LogoutHandler> logoutHandlers;
public void logout(HttpServletRequest request, HttpServletResponse response, Authentication authentication) {
for (LogoutHandler handler : this.logoutHandlers) {
handler.logout(request, response, authentication);
}
}
分析下来,与Delegating比较类似,不同的是,维护一个List<xxxHandler>
,构造函数同样支持传入指定的List<xxxHandler>
,然后在具体的handle
方法里(此处是logout
方法)for循环遍历list,分别使用具体的Handler来一一处理。类似地,下文也有几个CompositeXxxHandler,思想与此非常相似。
LogoutSuccessHandler
LogoutSuccessHandler接口,设置logout完成后需要处理动作,在LogoutHandler后被执行,LogoutHandler完成必要的动作(该过程不应该抛异常),LogoutSuccessHandler定位是处理后续更多的步骤,如重定向等,源码如下:
public interface LogoutSuccessHandler {
void onLogoutSuccess(HttpServletRequest request, HttpServletResponse response, Authentication authentication) throws IOException, ServletException;
}
有如下几个实现类:
- SimpleUrlLogoutSuccessHandler:和上面的AuthenticationSuccessHandler非常类似,继承AbstractAuthenticationTargetUrlRequestHandler,通过其中的handle方法实现请求重定向
- DelegatingLogoutSuccessHandler:
- HttpStatusReturningLogoutSuccessHandler:设置状态码200
- ForwardLogoutSuccessHandler:通过构造函数传入的目标URL,即targetUrl参数实现转发。
AccessDeniedHandler
AccessDeniedHandler接口,用来设置访问拒绝后的处理动作,源码如下:
public interface AccessDeniedHandler {
void handle(HttpServletRequest request, HttpServletResponse response, AccessDeniedException accessDeniedException) throws IOException, ServletException;
}
有如下几个实现类:
- NoOpAccessDeniedHandler:熟悉的NoOp。空实现,不做任何处理
- AccessDeniedHandlerImpl:设置403错误码,然后转发请求,让下一个Handler来处理
- DelegatingAccessDeniedHandler:
- CompositeAccessDeniedHandler:组合模式,for循环遍历各个Handler实现类,依次调用其handle方法进行处理
- InvalidSessionAccessDeniedHandler:清除缓存
- ObservationMarkingAccessDeniedHandler:
- RequestMatcherDelegatingAccessDeniedHandler:代理模式,维护一个map映射集合。根据具体的RequestMatcher匹配对应的Handler实现类,匹配成功则加以处理。最后使用defaultHandler加以处理。
- OAuth2AccessDeniedHandler:spring-security-oauth2包里面的实现类,同时继承AbstractOAuth2SecurityExceptionHandler类,直接调用父类里的handle方法。
CsrfTokenRequestHandler
CSRF,Cross-Site Request Forgery,跨站请求伪造是一种攻击技术,攻击者利用用户在已登录的状态下发起的请求来执行非法操作。
CsrfTokenRequestHandler是Spring Security种用于处理CSRF攻击的处理程序。具体来说,浏览器向服务器发送请求时,服务器会在响应中返回一个CSRF令牌。在后续的请求中浏览器将该令牌包含在请求中,服务器会验证该令牌的有效性,从而防止CSRF攻击。
函数式接口,源码如下:
@FunctionalInterface
public interface CsrfTokenRequestHandler extends CsrfTokenRequestResolver {
void handle(HttpServletRequest request, HttpServletResponse response, Supplier<CsrfToken> csrfToken);
default String resolveCsrfTokenValue(HttpServletRequest request, CsrfToken csrfToken) {
Assert.notNull(request, "request cannot be null");
Assert.notNull(csrfToken, "csrfToken cannot be null");
String actualToken = request.getHeader(csrfToken.getHeaderName());
if (actualToken == null) {
actualToken = request.getParameter(csrfToken.getParameterName());
}
return actualToken;
}
}
实现类包括:
- CsrfTokenRequestAttributeHandler
- XorCsrfTokenRequestAttributeHandler:执行异或xor运算
RequestRejectedHandler
位于org.springframework.security.web.firewall
包路径下,可知与防火墙策略相关,用于处理请求被拒绝的场景。当请求因为安全策略而被拒绝时,其实现类负责向用户发送相应的错误信息或执行其他定制的行为。
源码如下:
public interface RequestRejectedHandler {
void handle(HttpServletRequest request, HttpServletResponse response, RequestRejectedException requestRejectedException) throws IOException, ServletException;
}
实现类包括:
- DefaultRequestRejectedHandler:不做处理,抛出异常
- HttpStatusRequestRejectedHandler:通过
response.sendError(this.httpError);
发送错误响应状态码,默认400,支持构造方法传参 - ObservationMarkingRequestRejectedHandler:
- CompositeRequestRejectedHandler:组合模式,for循环遍历列表里的所有实现类,一一加以处理。
ObservationMarkingRequestRejectedHandler的handle方法如下:
private final ObservationRegistry registry;
public void handle(HttpServletRequest request, HttpServletResponse response, RequestRejectedException exception) throws IOException, ServletException {
Observation observation = this.registry.getCurrentObservation();
if (observation != null) {
observation.error(exception);
}
}
有点复杂。
ServerAuthenticationSuccessHandler
与AuthenticationSuccessHandler接口定义几乎一致,不同的是,只有一个非default方法,
HttpServletRequest request, HttpServletResponse response
两个参数变成一个参数WebFilterExchange webFilterExchange
,返回参数void
也变成响应式的Mono<Void>
public interface ServerAuthenticationSuccessHandler {
Mono<Void> onAuthenticationSuccess(WebFilterExchange webFilterExchange, Authentication authentication);
}
实现类:
- DelegatingServerAuthenticationSuccessHandler
- RedirectServerAuthenticationSuccessHandler
- WebFilterChainServerAuthenticationSuccessHandler
ServerAuthenticationFailureHandler
同上面的ServerAuthenticationSuccessHandler非常类似。实现类:
- RedirectServerAuthenticationFailureHandler
- ServerAuthenticationEntryPointFailureHandler
ServerLogoutHandler
与上面的非常相似,实现类:
- CsrfServerLogoutHandler
- DelegatingServerLogoutHandler
- HeaderWriterServerLogoutHandler
- OidcBackChannelServerLogoutHandler
- SecurityContextServerLogoutHandler
- WebSessionServerLogoutHandler:将WebFilterExchange里保存的WebSession做失效处理:
exchange.getExchange().getSession().flatMap(WebSession::invalidate);
ServerLogoutSuccessHandler
源码比较简单,实现类:
- HttpStatusReturningServerLogoutSuccessHandler
- RedirectServerLogoutSuccessHandler
ServerAccessDeniedHandler
ServerAccessDeniedHandler接口源码如下:
public interface ServerAccessDeniedHandler {
Mono<Void> handle(ServerWebExchange exchange, AccessDeniedException denied);
}
实现类:
- HttpStatusServerAccessDeniedHandler
- ServerWebExchangeDelegatingServerAccessDeniedHandler
ServerCsrfTokenRequestHandler
接口定义如下:
@FunctionalInterface
public interface ServerCsrfTokenRequestHandler extends ServerCsrfTokenRequestResolver {
void handle(ServerWebExchange exchange, Mono<CsrfToken> csrfToken);
default Mono<String> resolveCsrfTokenValue(ServerWebExchange exchange, CsrfToken csrfToken) {
Assert.notNull(exchange, "exchange cannot be null");
Assert.notNull(csrfToken, "csrfToken cannot be null");
return exchange.getFormData().flatMap((data) -> {
return Mono.justOrEmpty((String)data.getFirst(csrfToken.getParameterName()));
}).switchIfEmpty(Mono.justOrEmpty(exchange.getRequest().getHeaders().getFirst(csrfToken.getHeaderName())));
}
}
`