CAS SSO对手机应用支持的一种思路
我们知道，CAS SSO是一种WEB SSO，对针对WEB应用的单点登录解决方案。随着移动互联网应用崛起，通常应用群不仅包括WEB应用，常常也包含手机原生应用、桌面应用等C/S架构应用。如何让这些应用也纳入CAS认证服务器的管辖范围，统一认证、统一调度，是我们需要解决的问题。
手机和桌面应用访问CAS，我们不能直接使用CAS提供的web api。不过CAS提供了一个插件，叫CAS Restlet Integration，该插件提供了CAS API的Restful接口，这个接口可以被程序级调用，这样就给我们手机应用认证带来一种思路。首先，手机应用可以程序方式CAS认证服务器，获得TGT和ST，然后访问配置好CAS Client的应用Server，Server与CAS进行通信验证ST的有效性，如果有效即登录成功。登出处理比较简单，直接访问CAS API删除TGT即可，CAS会通知删除所有登录过应用的登录信息。
对 CAS Server，我们要安装Restlet Integration插件，
以CAS Server 3.4.5为例（CAS Server的基本配置参见 CAS Server 部署基本步骤），首先下载CAS Restlet Integration插件包及其依赖包（http://mvnrepository.com/artifact/org.jasig.cas/cas-server-integration-restlet/3.4.5），所需包名列表如下：
cas-server-integration-restlet-3.4.5.jar
cglib-nodep-2.1_3.jar
com.noelios.restlet.ext.servlet-1.1.1.jar
com.noelios.restlet.ext.spring-1.1.1.jar
com.noelios.restlet-1.1.1.jar
org.restlet.ext.spring-1.1.1.jar
org.restlet-1.1.1.jar
然后在web.xml中加入:
<!-- for restful api --><servlet> <servlet-name>restlet</servlet-name> <servlet-class>com.noelios.restlet.ext.spring.RestletFrameworkServlet</servlet-class> <load-on-startup>1</load-on-startup></servlet> <servlet-mapping> <servlet-name>restlet</servlet-name> <url-pattern>/v1/*</url-pattern></servlet-mapping>
程序获取TGT,ST和Logout，我们可以参考官方的例子：
/* 获取tgt和st的API接口是 /v1/tickets */private String getTicketGrantingTicket(final String server,final String username, final String password) {final HttpClient client = new HttpClient();final PostMethod post = new PostMethod(server);post.setRequestBody(new NameValuePair[] {new NameValuePair("username", username),new NameValuePair("password", password) });try {client.executeMethod(post);final String response = post.getResponseBodyAsString();switch (post.getStatusCode()) {case 200:return response;default:break;}} catch (Exception e) { } finally {post.releaseConnection();}return null;}@SuppressWarnings("unchecked")private String getServiceTicket(final String server,final String ticketGrantingTicket, final String service) {if (ticketGrantingTicket == null) return null;final HttpClient client = new HttpClient();final PostMethod post = new PostMethod(server + "/"+ ticketGrantingTicket);post.setRequestBody(new NameValuePair[] { new NameValuePair("service",service) });try {client.executeMethod(post);final String response = post.getResponseBodyAsString();switch (post.getStatusCode()) {case 200: return response;default:break;}} catch (Exception e) {} finally {post.releaseConnection();}return null;}
/* 删除tgt的API接口是 /v1/tickets/<tgt> ,delete方法 */public String logout(String tgt) {String result = "success";final HttpClient client = new HttpClient(); final DeleteMethod delete = new DeleteMethod(server + "/" + tgt); try { client.executeMethod(delete); final String response = delete.getResponseBodyAsString(); switch (delete.getStatusCode()) { case 200: break; default: result = "error";break; } } catch (IOException e) { result = "error";}finally{ delete.releaseConnection(); } return result;}