cas客户端流程详解(源码解析)--单点登录

博主之前一直使用了cas客户端进行用户的单点登录操作,决定进行源码分析来看cas的整个流程,以便以后出现了问题还不知道是什么原因导致的

cas主要的形式就是通过过滤器的形式来实现的,来,贴上示例配置:

 1     <listener>
 2         <listener-class>org.jasig.cas.client.session.SingleSignOutHttpSessionListener</listener-class>
 3     </listener>
 4 
 5     <filter>
 6         <filter-name>SSO Logout Filter</filter-name>
 7         <filter-class>org.jasig.cas.client.session.SingleSignOutFilter</filter-class>
 8     </filter>
 9 
10     <filter-mapping>
11         <filter-name>SSO Logout Filter</filter-name>
12         <url-pattern>/*</url-pattern>
13     </filter-mapping>
14 
15     <!-- SSO单点登录认证filter -->
16     <filter>
17         <filter-name>SSO Authentication Filter</filter-name>
18         <filter-class>org.jasig.cas.client.authentication.AuthenticationFilter</filter-class>
19         <init-param>
20             <!-- SSO服务器地址 -->
21             <param-name>SSOServerUrl</param-name>
22             <param-value>http://sso.jxeduyun.com/sso</param-value>
23         </init-param>
24         <init-param>
25             <!-- 统一登录地址 -->
26             <param-name>SSOLoginUrl</param-name>
27             <param-value>http://www.jxeduyun.com/App.ResourceCloud/Src/index.php</param-value>
28         </init-param>
29         <init-param>
30             <!-- 应用服务器地址, 域名或者[http://|https://]{ip}:{port} -->
31             <param-name>serverName</param-name>
32             <param-value>http://127.0.0.1:9000</param-value>
33         </init-param>
34         <init-param>
35             <!-- 除了openId,是否需要返回loginName以及userId等更多信息 -->
36             <param-name>needAttribute</param-name>
37             <param-value>true</param-value>
38         </init-param>
39         <init-param>
40             <!-- 可选,不需要单点登录的页面,多个页面以英文逗号分隔,支持正则表达式形式 -->
41             <!-- 例如:/abc/.*\.jsp,/.*/index\.jsp -->
42             <param-name>excludedURLs</param-name>
43             <param-value>/site2\.jsp</param-value>
44         </init-param>
45     </filter>
46 
47     <filter-mapping>
48         <filter-name>SSO Authentication Filter</filter-name>
49         <url-pattern>/TyrzLogin/*</url-pattern>
50     </filter-mapping>
51 
52     <!-- SSO ticket验证filter -->
53     <filter>
54         <filter-name>SSO Ticket Validation Filter</filter-name>
55         <filter-class>org.jasig.cas.client.validation.Cas20ProxyReceivingTicketValidationFilter</filter-class>
56         <init-param>
57             <!-- 应用服务器地址, 域名或者[http://|https://]{ip}:{port} -->
58             <param-name>serverName</param-name>
59             <param-value>http://127.0.0.1:9000</param-value>
60         </init-param>
61         <init-param>
62             <!-- 除了openId,是否需要返回loginName以及userId等更多信息 -->
63             <param-name>needAttribute</param-name>
64             <param-value>true</param-value>
65         </init-param>
66         <init-param>
67             <!-- SSO服务器地址前缀,用于生成验证地址,和SSOServerUrl保持一致 -->
68             <param-name>SSOServerUrlPrefix</param-name>
69             <param-value>http://sso.jxeduyun.com/sso</param-value>
70         </init-param>
71     </filter>
72 
73     <filter-mapping>
74         <filter-name>SSO Ticket Validation Filter</filter-name>
75         <url-pattern>/*</url-pattern>
76     </filter-mapping>
web.xml

 博主用的不是官方的cas的jar包,是第三方要求的又再次封装的jar包,不过就是属性,获取用户信息的逻辑多了点,其他的还是官方的源码,博主懒 的下载官方的jar在进行一步一步的debug看源码了。

基本配置是添加4个过滤器,请求的时候可以进行拦截进行查看,最后一个是jfinal的开发框架,类似spring,不用管,

 

 以上是jetty抓到请求时,进行获取过滤的流程,只关注cas的这四个,里面涉及到了缓存过滤器(节点类型存储)

 

全部进行路径URL匹配完之后,会获取到需要进行执行的过滤器,SSO Logout Filter->SSO Authentication Filter->SSO Ticket Validation Filter->CAS Assertion Thread Local Filter->jfinal->default

那我们就来一个一个看看,每个过滤器都做了哪些事。

SSO Logout Filter,从名字上看,应该是个退出的流程操作。来源吗附上:

 1 public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
 2         HttpServletRequest request = (HttpServletRequest)servletRequest;
 3         HttpServletResponse response = (HttpServletResponse)servletResponse;
 4         //查看请求中是否带有ticket参数
 5         if (!handler.isTokenRequest(request) && !CommonUtils.isNotBlank(request.getParameter("ticket"))) {
 6             //如果没有的ticket参数,查看是否是退出请求
 7             if (handler.isLogoutRequest(request)) {
 8                 if (this.sessionMappingStorage != null && !this.sessionMappingStorage.getClass().equals(HashMapBackedSessionMappingStorage.class)) {
 9                     //是退出请求,直接销毁session,直接return,不会在执行其他过滤器
10                     handler.destroySession(request, response);
11                     return;
12                 }
13             this.log.trace("Ignoring URI " + request.getRequestURI());
14         } else {
15             handler.recordSession(request);
16         }
17         ///继续执行下一个执行器
18         filterChain.doFilter(servletRequest, servletResponse);
19     }   
AuthenticationFilter,该过滤器主要做法:
 1 public final void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
 2         String requestedUrl = ((HttpServletRequest)servletRequest).getServletPath();
 3         boolean isExcludedUrl = false;
 4         //这里会获取到xml中的排除需要过滤的URL配置
 5         if (this.excludedRequestUrlPatterns != null && this.excludedRequestUrlPatterns.length > 0) {
 6             Pattern[] arr$ = this.excludedRequestUrlPatterns;
 7             int len$ = arr$.length;
 8 
 9             for(int i$ = 0; i$ < len$; ++i$) {
10                 Pattern p = arr$[i$];
11                 if (isExcludedUrl = p.matcher(requestedUrl).matches()) {
12                     break;
13                 }
14             }
15         }
16 
17         HttpServletRequest request = (HttpServletRequest)servletRequest;
18         HttpServletResponse response = (HttpServletResponse)servletResponse;
19         //如果当前URL是被排除,不需要校验cas单点登录的话,直接跳过当前过滤器,进行下一步
20         if (this.isIgnoreSSO() && isExcludedUrl) {
21             filterChain.doFilter(request, response);
22         } else {
23             //如果当前不被排除在外,查看白名单URL,也可以直接跳过该过滤器
24             boolean isWhiteUrl = false;
25             if (this.whiteRequestUrlPatterns != null && this.whiteRequestUrlPatterns.length > 0) {
26                 Pattern[] arr$ = this.whiteRequestUrlPatterns;
27                 int len$ = arr$.length;
28 
29                 for(int i$ = 0; i$ < len$; ++i$) {
30                     Pattern p = arr$[i$];
31                     if (isWhiteUrl = p.matcher(requestedUrl).matches()) {
32                         break;
33                     }
34                 }
35             }
36 
37             if (isWhiteUrl) {
38                 filterChain.doFilter(request, response);
39             } else {
40                 //如果都没匹配上,说明该URL是需要进行校验查看的
41                 HttpSession session = request.getSession(false);
42                 //从session中取出改属性值,查看当前session是否已经认证过了。如果认证过了了,可以跳过该过滤器
43                 Assertion assertion = session != null ? (Assertion)session.getAttribute("_const_cas_assertion_") : null;
44                 //第一次请求的时候,改对象一定为null,因为没人登录过
45                 if (assertion != null) {
46                     filterChain.doFilter(request, response);
47                 } else {
48                     String serviceUrl = this.constructServiceUrl(request, response);
49                     String ticket = CommonUtils.safeGetParameter(request, this.getArtifactParameterName());
50                     //查看是否session中有_const_cas_gateway_该属性值,第一次登录也没有
51                     boolean wasGatewayed = this.gatewayStorage.hasGatewayedAlready(request, serviceUrl);
52                     //如果都没有
53                     if (!CommonUtils.isNotBlank(ticket) && !wasGatewayed) {
54                         String encodedService;
55                         //查看是否是cas服务器return回调我们的这个接口请求,该属性值在下面,也就是第一次登录的时候,设置的
56                         if (request.getSession().getAttribute("casreturn") != null) {
57                             request.getSession().removeAttribute("casreturn");
58                             if (isExcludedUrl) {
59                                 filterChain.doFilter(request, response);
60                             } else {
61                                 encodedService = Base64.encodeBase64String(serviceUrl.getBytes());
62                                 encodedService = encodedService.replaceAll("[\\s*\t\n\r]", "");
63                                 if (!this.SSOLoginUrl.startsWith("https://") && !this.SSOLoginUrl.startsWith("http://")) {
64                                     this.SSOLoginUrl = this.getServerName() + (this.getServerName().endsWith("/") ? "" : "/") + this.SSOLoginUrl;
65                                 }
66                                 //-------------@这里----------------------
67                                 //一直以为是所有校验都没有参数后,在下面才是跳转到登录页,,没想到,直接回调了,并没有让用户去登陆,而是在这里才去调用登录页
68                                 //让用户去登陆。大坑
69                                 response.sendRedirect(CommonUtils.joinUrl(this.SSOLoginUrl, "nextpage=" + encodedService));
70                             }
71                         } else {
72                             //第一次登录的时候是这里,他会将你xml中的cas服务器地址拼接成login登录地址,我们当前请求的URL编码之后,会被cas登录成功后回调使用
73                             encodedService = this.SSOServerUrl + "/login?service=" + URLEncoder.encode(serviceUrl, "UTF-8") + "&redirect=true";
74                             //并且设置cas服务器回调标识
75                             request.getSession().setAttribute("casreturn", true);
76                             //第一次登录的时候,只能到这里了,因为ticket参数,或则session中_const_cas_assertion_属性都没有,只能去cas服务器请求登录,
77                             //这里有个坑,,没想到在这里没有直接出现登录页,而是调用cas服务器地址后,直接返回来了,而且会在@那里再去调用登录地址
78                             response.sendRedirect(encodedService);
79                             //其他的事情后续就不要再debug了,已经跟我们cas没有啥关系了,博主,debug了半天越看越懵,才发现是服务在做其他的事情,
80                             // 我们的登录页面早就已经出现了
81                         }
82                     } else {
83                         filterChain.doFilter(request, response);
84                     }
85                 }
86             }
87         }
88     }

上面的还有一个坑,就是,在用户登录成功后,回调我们的地址,第一次并不会带给我们ticket参数,而且还会走

ncodedService = this.SSOServerUrl + "/login?service=" + URLEncoder.encode(serviceUrl, "UTF-8") + "&redirect=true";
这个逻辑,并且附上casreturn属性,然后,cas服务器这回才会把ticket参数返回给我们的接口,剩下的就是下一个过滤器的事情了,慢慢来:

好了,这次有ticket了,我们来看下一个过滤器SSO Ticket Validation Filter

 1 public final void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
 2         //这里做了点事,是否为代理,博主没用这个,默认代理为null,返回true
 3         if (this.preFilter(servletRequest, servletResponse, filterChain)) {
 4             HttpServletRequest request = (HttpServletRequest)servletRequest;
 5             HttpServletResponse response = (HttpServletResponse)servletResponse;
 6             //获取ticket请求参数
 7             String ticket = CommonUtils.safeGetParameter(request, this.getArtifactParameterName());
 8             //到这里了,分为三种情况,
 9             //有ticket,因为你已经登录了,cas服务器登录成功返回给你了,接下来进行校验
10             //无ticket,可能你没有配置第一个过滤器,溜进来了
11             //无ticket,ticket已经校验成功后跳转回来了,用户属性已经设置到session中了,所以这次请求没有ticket了,不用去校验
12             if (CommonUtils.isNotBlank(ticket)) {
13                 if (this.log.isDebugEnabled()) {
14                     this.log.debug("Attempting to validate ticket: " + ticket);
15                 }
16 
17                 try {
18                     //开始ticket票据校验,这才是这个ticket过滤器真正要做的
19                     //constructServiceUrl这个方法不用管,就是拼接一下URL路径,把我的APPID啥的拼接上去
20                     //validate做了挺多事,请看下一个类注释,这里先过去(大概逻辑就是去cas服务器验证ticket)
21                     Assertion assertion = this.ticketValidator.validate(ticket, this.constructServiceUrl(request, response));
22                     if (this.log.isDebugEnabled()) {
23                         this.log.debug("Successfully authenticated user: " + assertion.getPrincipal().getName());
24                     }
25                     //看到这里没有,就是在第一个过滤器进行校验的参数,如果ticket验证成功,就会往request,及session设置属性,该属性就是_const_cas_assertion_
26                     //该属性值则是一个用户信息map
27                     request.setAttribute("_const_cas_assertion_", assertion);
28                     if (this.useSession) {
29                         request.getSession().setAttribute("_const_cas_assertion_", assertion);
30                     }
31                     //空方法,不用管
32                     this.onSuccessfulValidation(request, response, assertion);
33                     //ticket验证成功后,在进行跳转,这次是跳到我们自己的请求地址
34                     if (this.redirectAfterValidation) {
35                         this.log.debug("Redirecting after successful ticket validation.");
36                         response.sendRedirect(this.constructServiceUrl(request, response));
37                         return;
38                     }
39                 } catch (TicketValidationException var8) {
40                     response.setStatus(403);
41                     this.log.warn(var8, var8);
42                     this.onFailedValidation(request, response);
43                     if (this.exceptionOnValidationFailure) {
44                         throw new ServletException(var8);
45                     }
46 
47                     return;
48                 }
49             }
50 
51             filterChain.doFilter(request, response);
52         }
53     }

里面的ticket验证逻辑在此:

 1 public Assertion validate(String ticket, String service) throws TicketValidationException {
 2         //此处是拼接好要调用的URL
 3         //http://sso.jxeduyun.com/sso/,该路径是在web.xml中改ticket过滤器进行配置的SSOServerUrlPrefix
 4         //http://sso.jxeduyun.com/sso/serviceValidate?needAttribute=true&ticket=ST-28699-qdyblKpRwc5LpLk57dRM-sso.jxeduyun.com&service=http%3A%2F%2F127.0.0.1%3A9000%2Fdsideal_yy%2FdsTyrzLogin%2FssoLogin%3FloginType%3Dweb%26from%3Dew%26appId%3D00000&appKey=00000
 5         String validationUrl = this.constructValidationUrl(ticket, service);
 6         if (this.log.isDebugEnabled()) {
 7             this.log.debug("Constructing validation url: " + validationUrl);
 8         }
 9 
10         try {
11             this.log.debug("Retrieving response from server.");
12             //这里不用看,就是发起请求调用上面的接口,查看ticket有效性
13             String serverResponse = this.retrieveResponseFromServer(new URL(validationUrl), ticket);
14             if (serverResponse == null) {
15                 throw new TicketValidationException("The CAS server returned no response.");
16             } else {
17                 if (this.log.isDebugEnabled()) {
18                     this.log.debug("Server response: " + serverResponse);
19                 }
20                 //这个不用看了,就是解析返回的cas数据,然后获取里面的用户信息,并封装成map
21                 return this.parseResponseFromServer(serverResponse);
22             }
23         } catch (MalformedURLException var5) {
24             throw new TicketValidationException(var5);
25         }
26     }

因为ticket验证成功后并没有直接到下一个过滤器,而是从新请求了一次,这次不会有ticket参数了,因为session中已经有属性了,就在前几个过滤器中进行判断,在都走一次,然后才会到下面这个过滤器

 1 public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
 2         HttpServletRequest request = (HttpServletRequest)servletRequest;
 3         HttpSession session = request.getSession(false);
 4         Assertion assertion = (Assertion)((Assertion)(session == null ? request.getAttribute("_const_cas_assertion_") : session.getAttribute("_const_cas_assertion_")));
 5 
 6         try {
 7             //该过滤器的作用就是,把用户对象从session中拿出来,放到AssertionHolder里面,从而在代码中获取对象信息的时候,
 8             //直接调用该对象即可
 9             AssertionHolder.setAssertion(assertion);
10             filterChain.doFilter(servletRequest, servletResponse);
11         } finally {
12             AssertionHolder.clear();
13         }
14 
15     }

至此,cas的登录流程全部走完,不知道大家看懂多少,花了博主大概一天的时间才把源码理解通,ticket返回示例给大家一下,还有代码调用:

 1 失败示例:
 2 <cas:serviceResponse xmlns:cas='http://www.yale.edu/tp/cas'>
 3   <cas:authenticationFailure code='INVALID_TICKET'>
 4     ticket &#039;ST-28699-qdyblKpRwc5LpLk57dRM-sso.jxeduyun.com&#039; not recognized
 5   </cas:authenticationFailure>
 6 </cas:serviceResponse>
 7 成功示例:
 8 <cas:serviceResponse xmlns:cas='http://www.yale.edu/tp/cas'>
 9   <cas:authenticationSuccess>
10     <cas:user>test</cas:user>
11             <cas:attributes>
12                     <cas:multipleId>test-test-test-test-test</cas:multipleId>
13                 
14                     <cas:userId>test</cas:userId>
15                 
16                     <cas:loginName>test</cas:loginName>
17                 
18             </cas:attributes>
19   </cas:authenticationSuccess>
20 </cas:serviceResponse>

代码调用示例:

1         Assertion assertion = AssertionHolder.getAssertion();
2         String openId = assertion.getPrincipal().getName();
3         Map<String, Object> attributes = assertion.getPrincipal().getAttributes();
4         String userId = attributes.get("userId").toString();
5         String loginName = attributes.get("loginName").toString();
6         System.out.println("openId:"+openId);
7         System.out.println("userId:"+userId);
8         System.out.println("loginName:"+loginName);

 原创不易,转载请说明出处!谢谢

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posted @ 2020-07-11 16:16  努力的小雨  阅读(155)  评论(0编辑  收藏