CAS SSO对手机应用支持的一种思路

原文地址： http://architecture3.riaos.com/?p=3095368

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;
	}