UsernamePasswordAutheticationFilter源码解读和实践

UsernamePasswordAuthenticationFilter的目录

一、概述（重点）
二、标红小步骤解读
- 2.1 步骤1（标红1）
- - 2.1.1 AbstractAuthenticationProcessingFilter
  - 2.1.2 UsernamePasswordAuthenticationFilter
- 2.3 步骤2 和步骤3（标红2 和标红3）
- - 2.3.1 解读
  - 2.3.2 总结
- 2.4 步骤4（标红4）
- - 2.4.1 AbstractUserDetailsAuthenticationProvider
  - 2.4.2 DaoAuthenticationProvider
  - 2.4.3 总结 UserDetailsService & UserCache
三、说完源码，开始做实践
- 3.1 身份验证后置处理
- 3.2 前后端分离项目的登录配置
四、总结

如果你对SecurityFilterChain之前的过程存在疑惑，那么可以去研究一下下面两个内容，其实懂不懂下下面两个内容都不会影响你阅读本篇文章。

DelegatingFilterProxy
FilterProxyChain & SecurityFilterChain

下面会更新上面两个内容，可以关注一下 Spring源码研究导航

一、概述（重点）

第一步，主要对整个UsernamePasswordAutheticationFilter有一个全面的认知，这样读源码才事半功倍。下面会通过小章节对每一个标红的步骤进行解读。

在这里插入图片描述

二、标红小步骤解读

2.1 步骤1（标红1）

看一下UsernamePasswordAuthenticationFilter的继承图，还是相当复杂的，不过大多数都跟Spring有关，我们只需要关注AbstractAuthenticationProcessingFilter抽象类和Filter接口就差不多了。

2.1.1 AbstractAuthenticationProcessingFilter

先看AbstractAuthenticationProcessingFilter的doFilter方法，继承了Filter方法之后Servlet会执行doFilter，所以直接看doFiter方法就可以了。

public abstract class AbstractAuthenticationProcessingFilter extends GenericFilterBeanimplements ApplicationEventPublisherAware, MessageSourceAware {...@Overridepublic void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)throws IOException, ServletException {doFilter((HttpServletRequest) request, (HttpServletResponse) response, chain);}// doFilter逻辑主要有三个// 1. 通过attemptAuthentication对用户身份进行验证// 2. 身份验证成功之后执行successfulAuthentication// 3. 身份验证失败执行unsuccessfulAuthenticationprivate void doFilter(HttpServletRequest request, HttpServletResponse response, FilterChain chain)throws IOException, ServletException {// 判断请求是否符合过滤器的要求。// 使用RequestMatcher判断，判断的条件跟URL和请求方法有关。if (!requiresAuthentication(request, response)) {chain.doFilter(request, response);return;}try {// attemptAuthentication是子类UsernamePasswordAuthenticationFilter实现的。// 这个方法跟用户身份验证有关。Authentication authenticationResult = attemptAuthentication(request, response);if (authenticationResult == null) {return;}this.sessionStrategy.onAuthentication(authenticationResult, request, response);if (this.continueChainBeforeSuccessfulAuthentication) {chain.doFilter(request, response);}// 身份验证成功，successfulAuthentication(request, response, chain, authenticationResult);}catch (InternalAuthenticationServiceException failed) {this.logger.error("An internal error occurred while trying to authenticate the user.", failed);unsuccessfulAuthentication(request, response, failed);}catch (AuthenticationException ex) {unsuccessfulAuthentication(request, response, ex);}}...
}

身份验证成功之后的回调。

public class SavedRequestAwareAuthenticationSuccessHandler extends SimpleUrlAuthenticationSuccessHandler {protected final Log logger = LogFactory.getLog(this.getClass());private RequestCache requestCache = new HttpSessionRequestCache();// 负责重定向回原来的页面，下面有详细的解释。protected void successfulAuthentication(HttpServletRequest request, HttpServletResponse response, FilterChain chain,Authentication authResult) throws IOException, ServletException {// 保存认证成功之后的用户信息SecurityContext context = SecurityContextHolder.createEmptyContext();context.setAuthentication(authResult);SecurityContextHolder.setContext(context);this.securityContextRepository.saveContext(context, request, response);if (this.logger.isDebugEnabled()) {this.logger.debug(LogMessage.format("Set SecurityContextHolder to %s", authResult));}// 这个母鸡this.rememberMeServices.loginSuccess(request, response, authResult);if (this.eventPublisher != null) {this.eventPublisher.publishEvent(new InteractiveAuthenticationSuccessEvent(authResult, this.getClass()));}// 重定向到原始的访问地址，就比如：// 你访问localhost:8080/user，由于你没有认证，所以后端会让浏览器重定向到身份认证的页面http://localhost:8080/login// 你在http://localhost:8080/login网址通过了认证之后，后端会让浏览器重定向回localhost:8080/userthis.successHandler.onAuthenticationSuccess(request, response, authResult);}public void setRequestCache(RequestCache requestCache) {this.requestCache = requestCache;}}

身份验证失败之后的回调。

public class SimpleUrlAuthenticationFailureHandler implements AuthenticationFailureHandler {...// 失败处理也分三个部分// 1. 如果没有指定失败的重定向链接，那么直接调用response.sendError// 2. 如果指定了defaultFailureUrl，forwardToDestination=true，那么就把请求转发给defaultFailureUrl，这个是内部转发，共享request。// 3. 最后就是重定向了，重定向到defaultFailureUrl。@Overridepublic void onAuthenticationFailure(HttpServletRequest request, HttpServletResponse response,AuthenticationException exception) throws IOException, ServletException {if (this.defaultFailureUrl == null) {if (this.logger.isTraceEnabled()) {this.logger.trace("Sending 401 Unauthorized error since no failure URL is set");} else {this.logger.debug("Sending 401 Unauthorized error");}response.sendError(HttpStatus.UNAUTHORIZED.value(), HttpStatus.UNAUTHORIZED.getReasonPhrase());return;}saveException(request, exception);if (this.forwardToDestination) {this.logger.debug("Forwarding to " + this.defaultFailureUrl);request.getRequestDispatcher(this.defaultFailureUrl).forward(request, response);}else {this.redirectStrategy.sendRedirect(request, response, this.defaultFailureUrl);}}...
}

2.1.2 UsernamePasswordAuthenticationFilter

这个类主要看attemptAuthentication方法。

public class UsernamePasswordAuthenticationFilter extends AbstractAuthenticationProcessingFilter {...@Overridepublic Authentication attemptAuthentication(HttpServletRequest request, HttpServletResponse response) throws AuthenticationException {if (this.postOnly && !request.getMethod().equals("POST")) {throw new AuthenticationServiceException("Authentication method not supported: " + request.getMethod());}String username = obtainUsername(request);username = (username != null) ? username.trim() : "";String password = obtainPassword(request);password = (password != null) ? password : "";UsernamePasswordAuthenticationToken authRequest = UsernamePasswordAuthenticationToken.unauthenticated(username, password);setDetails(request, authRequest);// 这里就是要进入到我们红色圆圈2了。return this.getAuthenticationManager().authenticate(authRequest);}...
}

2.3 步骤2 和步骤3（标红2 和标红3）

2.3.1 解读

通过上面的分析，可以从UsernamePasswordAuthenticationFilter的return this.getAuthenticationManager().authenticate(authRequest)代码得知，UsernamePasswordAuthenticationFilter会把身份认证的任务抛给AuthenticationManager。接下来我们对AuthenticationManager进行分析，从下图得知ProviderManager实现了AuthenticationManager接口，这里主要是理解ProviderManager实现类。

下面主要看一下ProviderManager的核心属性（providers、parent）和核心方法authenticate。

public class ProviderManager implements AuthenticationManager, MessageSourceAware, InitializingBean {// 两个核心属性private List<AuthenticationProvider> providers = Collections.emptyList();private AuthenticationManager parent;// 方法主要有两个核心的方法// 1. 首先从认证提供器（AuthenticationProvider）里边做身份验证// 2. 如果认证提供器认证失败，那就继续给上一级的认证管理器（AuthenticationManager）做认证@Overridepublic Authentication authenticate(Authentication authentication) throws AuthenticationException {Class<? extends Authentication> toTest = authentication.getClass();AuthenticationException lastException = null;AuthenticationException parentException = null;Authentication result = null;Authentication parentResult = null;int currentPosition = 0;int size = this.providers.size();// 先遍历所有的AuthenticationProvider，通过他们去做身份验证。for (AuthenticationProvider provider : getProviders()) {if (!provider.supports(toTest)) {continue;}if (logger.isTraceEnabled()) {logger.trace(LogMessage.format("Authenticating request with %s (%d/%d)",provider.getClass().getSimpleName(), ++currentPosition, size));}try {result = provider.authenticate(authentication);if (result != null) {copyDetails(authentication, result);break;}}catch (AccountStatusException | InternalAuthenticationServiceException ex) {prepareException(ex, authentication);// SEC-546: Avoid polling additional providers if auth failure is due to// invalid account statusthrow ex;}catch (AuthenticationException ex) {lastException = ex;}}// 如果所有的AuthenticationProvider的身份验证都失败了，那么去找ProviderManager父级。if (result == null && this.parent != null) {try {parentResult = this.parent.authenticate(authentication);result = parentResult;}catch (ProviderNotFoundException ex) {// ignore as we will throw below if no other exception occurred prior to// calling parent and the parent// may throw ProviderNotFound even though a provider in the child already// handled the request}catch (AuthenticationException ex) {parentException = ex;lastException = ex;}}if (result != null) {if (this.eraseCredentialsAfterAuthentication && (result instanceof CredentialsContainer)) {((CredentialsContainer) result).eraseCredentials();}if (parentResult == null) {this.eventPublisher.publishAuthenticationSuccess(result);}return result;}if (lastException == null) {lastException = new ProviderNotFoundException(this.messages.getMessage("ProviderManager.providerNotFound",new Object[] { toTest.getName() }, "No AuthenticationProvider found for {0}"));}if (parentException == null) {prepareException(lastException, authentication);}throw lastException;}}

2.3.2 总结

从ProviderManager的authenticate方法中可以总结出下图的结构，虽然有点抽象。主要表达的意思是，ProviderManager内部维护了一堆AuthenticationProvider和父级AuthenticationManager，authenticate的逻辑是先把认证交给一堆AuthenticationProvider做认证，AuthenticationProvider认证失败了才交给父级。

在这里插入图片描述

2.4 步骤4（标红4）

上面# 三、步骤2 和步骤3（标红2 和标红3）对AuthenticationProvider做了一个介绍，最终的身份认证会交给它，现在我们对它做详细的介绍。AuthenticationProvider有超级多的实现类，我们只需要关注AbstractUserDetailsAuthenticationProvider抽象类，以及抽象类的实现类DaoAuthenticationProvider。

2.4.1 AbstractUserDetailsAuthenticationProvider

因为AbstractUserDetailsAuthenticationProvider实现了AuthenticationProvider接口，所以我们直接挑authenticate来看。
下面方法主要看两个方法

查缓存，如果缓存有用户，就直接返回了。可以发现默认实现是NullUserCache，啥也不做。
做身份验证的retrieveUser方法，这是一个抽象方法，所有我们要看子类DaoAuthentiationProvider。

public abstract class AbstractUserDetailsAuthenticationProviderimplements AuthenticationProvider, InitializingBean, MessageSourceAware {private UserCache userCache = new NullUserCache();@Overridepublic Authentication authenticate(Authentication authentication) throws AuthenticationException {Assert.isInstanceOf(UsernamePasswordAuthenticationToken.class, authentication, () -> this.messages.getMessage("AbstractUserDetailsAuthenticationProvider.onlySupports", "Only UsernamePasswordAuthenticationToken is supported"));String username = determineUsername(authentication);boolean cacheWasUsed = true;// 查缓存，这里也可以进行扩展，我们可以把缓存实现成RedisUserDetails user = this.userCache.getUserFromCache(username);if (user == null) {cacheWasUsed = false;try {// 调用抽象方法user = retrieveUser(username, (UsernamePasswordAuthenticationToken) authentication);}catch (UsernameNotFoundException ex) {this.logger.debug("Failed to find user '" + username + "'");if (!this.hideUserNotFoundExceptions) {throw ex;}throw new BadCredentialsException(this.messages .getMessage("AbstractUserDetailsAuthenticationProvider.badCredentials", "Bad credentials"));}Assert.notNull(user, "retrieveUser returned null - a violation of the interface contract");}try {this.preAuthenticationChecks.check(user);additionalAuthenticationChecks(user, (UsernamePasswordAuthenticationToken) authentication);}catch (AuthenticationException ex) {if (!cacheWasUsed) {throw ex;}// There was a problem, so try again after checking// we're using latest data (i.e. not from the cache)cacheWasUsed = false;user = retrieveUser(username, (UsernamePasswordAuthenticationToken) authentication);this.preAuthenticationChecks.check(user);additionalAuthenticationChecks(user, (UsernamePasswordAuthenticationToken) authentication);}this.postAuthenticationChecks.check(user);if (!cacheWasUsed) {this.userCache.putUserInCache(user);}Object principalToReturn = user;if (this.forcePrincipalAsString) {principalToReturn = user.getUsername();}return createSuccessAuthentication(principalToReturn, authentication, user);}protected abstract UserDetails retrieveUser(String username, UsernamePasswordAuthenticationToken authentication) throws AuthenticationException;
}

2.4.2 DaoAuthenticationProvider

public abstract class AbstractUserDetailsAuthenticationProvider implements AuthenticationProvider, InitializingBean, MessageSourceAware {@Overrideprotected final UserDetails retrieveUser(String username, UsernamePasswordAuthenticationToken authentication) throws AuthenticationException {prepareTimingAttackProtection();try {// 这里就是我们自己扩展的地方了，调用UserDetailsService.loadUserByUsernameUserDetails loadedUser = this.getUserDetailsService().loadUserByUsername(username);if (loadedUser == null) {throw new InternalAuthenticationServiceException("UserDetailsService returned null, which is an interface contract violation");}return loadedUser;}catch (UsernameNotFoundException ex) {mitigateAgainstTimingAttack(authentication);throw ex;}catch (InternalAuthenticationServiceException ex) {throw ex;}catch (Exception ex) {throw new InternalAuthenticationServiceException(ex.getMessage(), ex);}}
}

2.4.3 总结 UserDetailsService & UserCache

上面的AbstractUserDetailsAuthenticationProvider的authenticate方法逻辑是先查缓存（UserCache），再交给UserDetailsService。那如何自定义自己的UserDetailsService和UserCache呢？在下个大章节说。

三、说完源码，开始做实践

3.1 身份验证后置处理

主要是failureHandler.setUseForward(true)，如果设置为false就重定向，如果设置为true就是内部转发。

@EnableWebSecurity
public class SpringSecurityConfig {@Autowiredpublic void configure(AuthenticationManagerBuilder builder) throws Exception {builder.inMemoryAuthentication().passwordEncoder(new BCryptPasswordEncoder()).withUser(User.withUsername("admin").password(new BCryptPasswordEncoder().encode("123")).roles("admin"));}@Beanpublic SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {http.formLogin().failureHandler(buildAuthenticationFailureHandler()).successHandler(buildSimpleUrlAuthenticationSuccessHandler());return http.build();}// 失败后置处理SimpleUrlAuthenticationFailureHandler buildAuthenticationFailureHandler() {SimpleUrlAuthenticationFailureHandler failureHandler = new SimpleUrlAuthenticationFailureHandler();failureHandler.setUseForward(true);failureHandler.setDefaultFailureUrl("/other/login/fail");return failureHandler;}
}@RestController
@RequestMapping("/other")
public class UserController {@PostMapping("/login/fail")public AjaxResult fail() {return AjaxResult.failure("账号或密码错误！");}@PostMapping("/login/success")public AjaxResult success() {Authentication authentication = SecurityContextHolder.getContext().getAuthentication();return AjaxResult.success("登录成功！", authentication.getPrincipal());}
}

登录失败的效果

在这里插入图片描述登录成功的效果

3.2 前后端分离项目的登录配置

这个配置加上了登录的后置处理，重点在移除了自带的登录页面，设置了登录url，有的同学很懵逼，我解释一下，设置了登录url之后UsernamePasswordAuthenticationFilter会拦截/user/login做登录处理，然后就是走我们# 一、概述（重点）那个图的整个过程了

@EnableWebSecurity
public class SpringSecurityConfig {@Autowiredpublic void configure(AuthenticationManagerBuilder builder) throws Exception {builder.inMemoryAuthentication().passwordEncoder(new BCryptPasswordEncoder()).withUser(User.withUsername("admin").password(new BCryptPasswordEncoder().encode("123")).roles("admin"));}@Beanpublic SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {// 关闭自带的登录页面http.getConfigurer(DefaultLoginPageConfigurer.class).disable();http.formLogin().failureHandler(buildAuthenticationFailureHandler()).successHandler(buildSimpleUrlAuthenticationSuccessHandler())// 设置登录url.loginProcessingUrl("/user/login").and().csrf().disable();return http.build();}// 登录失败处理器SimpleUrlAuthenticationFailureHandler buildAuthenticationFailureHandler() {SimpleUrlAuthenticationFailureHandler failureHandler = new SimpleUrlAuthenticationFailureHandler();failureHandler.setUseForward(true);failureHandler.setDefaultFailureUrl("/other/login/fail");return failureHandler;}// 登录成功处理器，内部转发AuthenticationSuccessHandler buildSimpleUrlAuthenticationSuccessHandler() {return ((request, response, authentication) -> request.getRequestDispatcher("/other/login/success").forward(request, response));}
}@RestController
@RequestMapping("/other")
public class UserController {@PostMapping("/login/fail")public AjaxResult fail() {return AjaxResult.failure("账号或密码错误！");}@PostMapping("/login/success")public AjaxResult success() {Authentication authentication = SecurityContextHolder.getContext().getAuthentication();return AjaxResult.success("登录成功！", authentication.getPrincipal());}
}