[原]cas-client单点登录客户端拦截请求和忽略/排除不需要拦截的请求URL的问题

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eguid 6月 22, 2017
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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。


<div>
    作者:eguid_1 发表于 2017/06/22 23:43:59 [原文链接](https://blog.csdn.net/eguid_1/article/details/73611781) https://blog.csdn.net/eguid_1/article/details/73611781                    </div>
<div>
    阅读:3912 评论:5 [查看评论](https://blog.csdn.net/eguid_1/article/details/73611781#comments)                    </div>

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本文链接:https://blog.eguid.cc/2017/06/22/原-cas-client单点登录客户端拦截请求和忽略-排除不需要拦截的请求URL的问题/