前言:今天在网上无意间看到cas单点登录排除请求的问题,发现很多人在讨论如何通过改写AuthenticationFilter类来实现忽略/排除请求URL的功能;突发奇想搜了一下,还真蛮多人都是这么干的,原谅我是个耿直的boy,当时我笑的饭都喷出来了,只需要一个配置的问题,被你们搞的这么麻烦;虽然很想回复他们“你们这帮人用别人的东西都不看源码的吗?”,转念一想,这也要怪作者不给力,文档里压根没有提到这个配置,在这里用少量篇幅讲解如何配置排除不需要拦截的请求URL,后面用大量篇幅介绍我是如何从源码中得知这个配置的,希望对大家有用!做好自己!--eguid始终坚持原创的开源技术文章分享,博客园与本博客保持同步更新。欢迎大家加群一起交流:608423839
1、cas-client单点登录配置
http://blog.csdn.net/eguid_1/article/details/51278622,cas-client完整配置。
没有实现忽略/排除请求URL的cas-client登录验证过滤器
<filter> <filter-name>casAuthenticationFilter</filter-name> <filter-class>org.jasig.cas.client.authentication.AuthenticationFilter</filter-class> <init-param> <param-name>casServerLoginUrl</param-name> <param-value>https://cas.eguid.cc/cas-server/</param-value> </init-param> <init-param> <param-name>serverName</param-name> <param-value>http://client.eguid.cc/</param-value> </init-param> </filter> <filter-mapping> <filter-name>casAuthenticationFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping>
这个配置依然是可用的,当然我们要实现忽略/排除请求URL的功能,那么我们该怎么做呢?
2、忽略/排除多个请求URL
<filter> <filter-name>casAuthenticationFilter</filter-name> <filter-class>org.jasig.cas.client.authentication.AuthenticationFilter</filter-class> <init-param> <param-name>casServerLoginUrl</param-name> <param-value>http://cas.eguid.cc/cas-server/</param-value> </init-param> <init-param> <param-name>serverName</param-name> <param-value>http://cilent.eguid.cc/</param-value> </init-param> <init-param> <description>不拦截的请求(做好自己!--eguid)</description> <param-name>ignorePattern</param-name> <param-value>/js/*|/img/*|/view/*|/css/*</param-value> </init-param> </filter> <filter-mapping> <filter-name>casAuthenticationFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping>
如上所见,我们排除了四个请求URL(必须是正则表达式形式,下面会讲为什么要这么配置)
3、cas-client默认登录验证过滤器源码解析
看源码,一定要带着目的去看;我们的目的就是找AuthenticationFilter这个cas-client默认登录验证过滤器是否具有排除登录请求URL的功能。
(1)打开cas-client项目源码
打开github上的cas-client项目,可以把项目导到本地或者直接在github上找到org.jasig.cas.client.authentication.AuthenticationFilter.java这个类。
(2)登录验证过滤器AuthenticationFilter的doFilter
既然是个过滤器,就直接找到该类的doFilter方法
public final void doFilter(final ServletRequest servletRequest, final ServletResponse servletResponse, final FilterChain filterChain) throws IOException, ServletException { <!--做好自己!eguid原创--> final HttpServletRequest request = (HttpServletRequest) servletRequest; final HttpServletResponse response = (HttpServletResponse) servletResponse; if (isRequestUrlExcluded(request)) { logger.debug("Request is ignored."); filterChain.doFilter(request, response); return; } final HttpSession session = request.getSession(false); final Assertion assertion = session != null ? (Assertion) session.getAttribute(CONST_CAS_ASSERTION) : null; if (assertion != null) { filterChain.doFilter(request, response); return; } final String serviceUrl = constructServiceUrl(request, response); final String ticket = retrieveTicketFromRequest(request); final boolean wasGatewayed = this.gateway && this.gatewayStorage.hasGatewayedAlready(request, serviceUrl); if (CommonUtils.isNotBlank(ticket) || wasGatewayed) { filterChain.doFilter(request, response); return; } final String modifiedServiceUrl; logger.debug("no ticket and no assertion found"); if (this.gateway) { logger.debug("setting gateway attribute in session"); modifiedServiceUrl = this.gatewayStorage.storeGatewayInformation(request, serviceUrl); } else { modifiedServiceUrl = serviceUrl; } logger.debug("Constructed service url: {}", modifiedServiceUrl); final String urlToRedirectTo = CommonUtils.constructRedirectUrl(this.casServerLoginUrl, getProtocol().getServiceParameterName(), modifiedServiceUrl, this.renew, this.gateway); logger.debug("redirecting to \"{}\"", urlToRedirectTo); this.authenticationRedirectStrategy.redirect(request, response, urlToRedirectTo); }
(3)isRequestUrlExcluded方法
第一眼就看到了上面代码红色标识处的isRequestUrlExcluded,这个意思很直白,判断是不是需要忽略/排除的请求URL。
继续接着找到isRequestUrlExcluded这个方法的实现代码:
private boolean isRequestUrlExcluded(final HttpServletRequest request) { if (this.ignoreUrlPatternMatcherStrategyClass == null) { return false; } <!--做好自己!eguid原创--> final StringBuffer urlBuffer = request.getRequestURL(); if (request.getQueryString() != null) { urlBuffer.append("?").append(request.getQueryString()); } final String requestUri = urlBuffer.toString(); return this.ignoreUrlPatternMatcherStrategyClass.matches(requestUri); }看红色标识位置的名字,这里用到了UrlPatternMatcherStrategy这个类,意思很简单直白:‘请求url的匹配策略类’,暂时还不知道这里是正则匹配,往后看:
(4)请求URL的匹配策略类UrlPatternMatcherStrategy
private UrlPatternMatcherStrategy ignoreUrlPatternMatcherStrategyClass = null;发现该类是在初始化方法中进行初始化的:
protected void initInternal(final FilterConfig filterConfig) throws ServletException { if (!isIgnoreInitConfiguration()) { super.initInternal(filterConfig); setCasServerLoginUrl(getString(ConfigurationKeys.CAS_SERVER_LOGIN_URL)); setRenew(getBoolean(ConfigurationKeys.RENEW)); setGateway(getBoolean(ConfigurationKeys.GATEWAY)); <!--做好自己!eguid原创--> final String ignorePattern = getString(ConfigurationKeys.IGNORE_PATTERN); final String ignoreUrlPatternType = getString(ConfigurationKeys.IGNORE_URL_PATTERN_TYPE); if (ignorePattern != null) { final Class<? extends UrlPatternMatcherStrategy> ignoreUrlMatcherClass = PATTERN_MATCHER_TYPES.get(ignoreUrlPatternType); if (ignoreUrlMatcherClass != null) { this.ignoreUrlPatternMatcherStrategyClass = ReflectUtils.newInstance(ignoreUrlMatcherClass.getName()); } else { try { logger.trace("Assuming {} is a qualified class name...", ignoreUrlPatternType); this.ignoreUrlPatternMatcherStrategyClass = ReflectUtils.newInstance(ignoreUrlPatternType); } catch (final IllegalArgumentException e) { logger.error("Could not instantiate class [{}]", ignoreUrlPatternType, e); } } if (this.ignoreUrlPatternMatcherStrategyClass != null) { this.ignoreUrlPatternMatcherStrategyClass.setPattern(ignorePattern); } } final Class<? extends GatewayResolver> gatewayStorageClass = getClass(ConfigurationKeys.GATEWAY_STORAGE_CLASS); if (gatewayStorageClass != null) { setGatewayStorage(ReflectUtils.newInstance(gatewayStorageClass)); } final Class<? extends AuthenticationRedirectStrategy> authenticationRedirectStrategyClass = getClass(ConfigurationKeys.AUTHENTICATION_REDIRECT_STRATEGY_CLASS); if (authenticationRedirectStrategyClass != null) { this.authenticationRedirectStrategy = ReflectUtils.newInstance(authenticationRedirectStrategyClass); } } }虽然使用了反射,但是依然不影响我们找到根本所在,找到ConfigurationKeys这个类里面的变量究竟是什么:
ConfigurationKey<String> IGNORE_PATTERN = new ConfigurationKey<String>("ignorePattern", null); ConfigurationKey<String> IGNORE_URL_PATTERN_TYPE = new ConfigurationKey<String>("ignoreUrlPatternType", "REGEX");字面上理解这两个常量定义了忽略模式以及忽略模式类型是‘正则’,当然我们还是不确定是不是正则,那么继续往下找
final Class<? extends UrlPatternMatcherStrategy> ignoreUrlMatcherClass = PATTERN_MATCHER_TYPES.get(ignoreUrlPatternType);
我们已经通过ConfigurationKeys类知道ignoreUrlPatternType是个‘REGEX’字符串,那么
PATTERN_MATCHER_TYPES.put("REGEX", RegexUrlPatternMatcherStrategy.class);那么按照REGEX对应的值找到 RegexUrlPatternMatcherStrategy这个类:
(5)确定RegexUrlPatternMatcherStrategy类用于处理正则验证匹配
public final class RegexUrlPatternMatcherStrategy implements UrlPatternMatcherStrategy { <!--做好自己!eguid原创--> private Pattern pattern; public RegexUrlPatternMatcherStrategy() {} public RegexUrlPatternMatcherStrategy(final String pattern) { this.setPattern(pattern); } public boolean matches(final String url) { return this.pattern.matcher(url).find(); } public void setPattern(final String pattern) { this.pattern = Pattern.compile(pattern); } }该类中用到了Pattern来编译和匹配正则表达式
到这里我们终于可以确定可以用ignorePattern来忽略/排除我们不需要拦截的请求URL,当然必须满足正则表达式。