?2021年的最后2个月，立个flag，要把Spring Security和Spring Security OAuth2的应用及主流程源码研究透彻！
?项目中使用过Spring Security的童鞋都知道，当我们没有单独自定义登录页时，Spring Security自己在初始化的时候会帮我们配置一个默认的登录页，之前一直疑问默认登录页是怎么配置的，今晚特地找了源码跟一下。
springboot项目依赖
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<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-security</artifactId> </dependency> |
在项目中随意编写一个接口，然后进行访问
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@GetMapping ( "/" ) public String hello() { return "hello, spring security" ; } |
在tomcat默认端口8080，localhost:8080 下访问该接口，spring security会帮我们将路径重定向到默认的登录页
?那么这个默认页是怎么来的呢？
原来Spring Security有一个默认的WebSecurityConfigurerAdapter，发现其中有一个init方法，于是在这个方法打了断点，在应用启动的时候进行跟踪。
?跟踪getHttp()方法，this.disableDefaults变量默认为false，意味着将会执行 applyDefaultConfiguration(this.http); 方法。查看 applyDefaultConfiguration 方法
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public void init(WebSecurity web) throws Exception { // 首先配置security要拦截的哪些http请求 HttpSecurity http = getHttp(); web.addSecurityFilterChainBuilder(http).postBuildAction(() -> { FilterSecurityInterceptor securityInterceptor = http.getSharedObject(FilterSecurityInterceptor. class ); web.securityInterceptor(securityInterceptor); }); }
protected final HttpSecurity getHttp() throws Exception { if ( this .http != null ) { return this .http; } AuthenticationEventPublisher eventPublisher = getAuthenticationEventPublisher(); this .localConfigureAuthenticationBldr.authenticationEventPublisher(eventPublisher); AuthenticationManager authenticationManager = authenticationManager(); this .authenticationBuilder.parentAuthenticationManager(authenticationManager); Map<Class<?>, Object> sharedObjects = createSharedObjects(); this .http = new HttpSecurity( this .objectPostProcessor, this .authenticationBuilder, sharedObjects); if (! this .disableDefaults) { // 默认的配置将会走这个分支 applyDefaultConfiguration( this .http); ClassLoader classLoader = this .context.getClassLoader(); List<AbstractHttpConfigurer> defaultHttpConfigurers = SpringFactoriesLoader .loadFactories(AbstractHttpConfigurer. class , classLoader); for (AbstractHttpConfigurer configurer : defaultHttpConfigurers) { this .http.apply(configurer); } } configure( this .http); return this .http; } |
查看 applyDefaultConfiguration(this.http) 方法，发现http对象new了一个 DefaultLoginPageConfigurer 对象属性，
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private void applyDefaultConfiguration(HttpSecurity http) throws Exception { http.csrf(); http.addFilter( new WebAsyncManagerIntegrationFilter()); http.exceptionHandling(); http.headers(); http.sessionManagement(); http.securityContext(); http.requestCache(); http.anonymous(); http.servletApi(); http.apply( new DefaultLoginPageConfigurer<>()); http.logout(); } |
?查看 DefaultLoginPageConfigurer 类定义，发现它在初始化的同时，它也初始化了自己的2个私有成员变量，分别是 DefaultLoginPageGeneratingFilter 默认登录页面生成Filter, DefaultLogoutPageGeneratingFilter 默认登录页面Filter, 名字起得很好，见名知意，我们马山知道这2个类的含义。
?查看 DefaultLoginPageGeneratingFilter 的类成员变量，发现定义了一系列跟登录有关的成员变量，包括登录、登录等路径，默认的登录页面路径是 "/login"
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public class DefaultLoginPageGeneratingFilter extends GenericFilterBean {
public static final String DEFAULT_LOGIN_PAGE_URL = "/login" ;
public static final String ERROR_PARAMETER_NAME = "error" ;
private String loginPageUrl;
private String logoutSuccessUrl;
private String failureUrl;
private boolean formLoginEnabled; ..... |
?再结合类名思考，发现是个Filter类，那么它们应该都会重新Filter的 doFilter(ServletRequest request, ServletResponse response, FilterChain chain) 方法，我们查看一下 DefaultLoginPageConfigurer 类的``doFilter 方法，果然，在 doFilter`方法中发现了生成默认登录页面的方法。
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private void doFilter(HttpServletRequest request, HttpServletResponse response, FilterChain chain) throws IOException, ServletException { // 判断当前的请求是否被认证通过 boolean loginError = isErrorPage(request); boolean logoutSuccess = isLogoutSuccess(request); if (isLoginUrlRequest(request) || loginError || logoutSuccess) { // 当前请求认证失败的话，将会执行这个分支 String loginPageHtml = generateLoginPageHtml(request, loginError, logoutSuccess); response.setContentType( "text/html;charset=UTF-8" ); response.setContentLength(loginPageHtml.getBytes(StandardCharsets.UTF_8).length); response.getWriter().write(loginPageHtml); return ; } chain.doFilter(request, response); }
private String generateLoginPageHtml(HttpServletRequest request, boolean loginError, boolean logoutSuccess) { String errorMsg = "Invalid credentials" ; if (loginError) { HttpSession session = request.getSession( false ); if (session != null ) { AuthenticationException ex = (AuthenticationException) session .getAttribute(WebAttributes.AUTHENTICATION_EXCEPTION); errorMsg = (ex != null ) ? ex.getMessage() : "Invalid credentials" ; } } String contextPath = request.getContextPath(); StringBuilder sb = new StringBuilder(); sb.append( "<!DOCTYPE html>\n" ); sb.append( "<html lang=\"en\">\n" ); sb.append( " <head>\n" ); sb.append( " <meta charset=\"utf-8\">\n" ); sb.append( " <meta name=\"viewport\" content=\"width=device-width, initial-scale=1, shrink-to-fit=no\">\n" ); sb.append( " <meta name=\"description\" content=\"\">\n" ); sb.append( " <meta name=\"author\" content=\"\">\n" ); sb.append( " <title>Please sign in</title>\n" ); sb.append( " <link href=\"https://maxcdn.bootstrapcdn测试数据/bootstrap/4.0.0-beta/css/bootstrap.min.css\" " + "rel=\"stylesheet\" integrity=\"sha384-/Y6pD6FV/Vv2HJnA6t+vslU6fwYXjCFtcEpHbNJ0lyAFsXTsjBbfaDjzALeQsN6M\" crossorigin=\"anonymous\">\n" ); sb.append( " <link href=\"https://getbootstrap测试数据/docs/4.0/examples/signin/signin.css\" " + "rel=\"stylesheet\" crossorigin=\"anonymous\"/>\n" ); sb.append( " </head>\n" ); sb.append( " <body>\n" ); sb.append( " <div class=\"container\">\n" ); if ( this .formLoginEnabled) { sb.append( " <form class=\"form-signin\" method=\"post\" action=\"" + contextPath + this .authenticationUrl + "\">\n" ); sb.append( " <h2 class=\"form-signin-heading\">Please sign in</h2>\n" ); sb.append(createError(loginError, errorMsg) + createLogoutSuccess(logoutSuccess) + " <p>\n" ); sb.append( " <label for=\"username\" class=\"sr-only\">Username</label>\n" ); sb.append( " <input type=\"text\" id=\"username\" name=\"" + this .usernameParameter + "\" class=\"form-control\" placeholder=\"Username\" required autofocus>\n" ); sb.append( " </p>\n" ); sb.append( " <p>\n" ); sb.append( " <label for=\"password\" class=\"sr-only\">Password</label>\n" ); sb.append( " <input type=\"password\" id=\"password\" name=\"" + this .passwordParameter + "\" class=\"form-control\" placeholder=\"Password\" required>\n" ); sb.append( " </p>\n" ); sb.append(createRememberMe( this .rememberMeParameter) + renderHiddenInputs(request)); sb.append( " <button class=\"btn btn-lg btn-primary btn-block\" type=\"submit\">Sign in</button>\n" ); sb.append( " </form>\n" ); } if ( this .openIdEnabled) { sb.append( " <form name=\"oidf\" class=\"form-signin\" method=\"post\" action=\"" + contextPath + this .openIDauthenticationUrl + "\">\n" ); sb.append( " <h2 class=\"form-signin-heading\">Login with OpenID Identity</h2>\n" ); ...... return sb.toString(); } |
?我们发现 generateLoginPageHtml(HttpServletRequest request, boolean loginError, boolean logoutSuccess) 这个方法中使用了最原始的Servlet写html页面的方法，将登录页的html代码写到字符串中写出到前端展示。到这里，我们就大体知道默认登录页面及登出页面是怎么生成的了。
?默认登录页到这里就结束了，有兴趣的可以关注下，接下来会继续写springsecurity的自定义表单认证、授权、会话等内容剖析。距离2022年只剩54天!
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原文链接：https://HdhCmsTestcnblogs测试数据/process-h/p/15522267.html
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