CAS学习之RESTFUL API使用（1）

CAS环境搭建完成之后，由于项目中需要模拟CAS登陆并获取相应的TICKET，专门学习了一下RESTFUL API的使用。
以下例子代码实现的功能是模拟登陆CAS，生成ST为各个集成了CAS的应用使用。

将RESTFUL API的调用封装到了一个类中：

package com.feiquan16.cas.util;
import java.io.IOException;
import java.util.StringTokenizer;
import java.util.logging.Logger;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.NameValuePair;
import org.apache.commons.httpclient.methods.PostMethod;
/**
* An example Java client to authenticate against CAS using REST services.
* Please ensure you have followed the necessary setup found on the <a
* href="http://www.ja-sig.org/wiki/display/CASUM/RESTful+API">wiki</a>.
*
* @author <a href="mailto:jieryn@gmail.com">jesse lauren farinacci</a>
* @since 3.4.2
*/
public final class CASUtility {
private static final Logger LOG = Logger.getLogger(CASUtility.class.getName());
public static PropertiesReader pr = null;
private CASUtility() {
// static-only access
}
public static String getTicket(final HttpServletRequest request,
final HttpServletResponse response, final String server,
final String username, final String password, final String service) {
notNull(server, "server must not be null");
notNull(username, "username must not be null");
notNull(password, "password must not be null");
notNull(service, "service must not be null");
return getServiceTicket(request, response, server, getTicketGrantingTicket(response, server, username, password), service);
}
private static String getServiceTicket(final HttpServletRequest request,
final HttpServletResponse res, final String server,
final String ticketGrantingTicket, final String service) {
if (ticketGrantingTicket == null)
return null;
res.setHeader("P3P","CP=CAO PSA OUR");

String broswer = "";
try {
String agent = request.getHeader("User-Agent");
StringTokenizer st = new StringTokenizer(agent,";");
st.nextToken();
broswer = st.nextToken();
LOG.info("User's Browser is "+broswer);
}catch(Exception e) {
LOG.info("Fail to get User's Browser Type.");
}

LOG.info("ticketGrantingTicket : " + ticketGrantingTicket);
Cookie c1 = new Cookie("CASTGC", ticketGrantingTicket);

pr = PropertiesReader.getInstance("");
String domain = pr.getPropertiy("cas.server.domain");
if (broswer != null && broswer.trim().startsWith("MSIE")){
c1.setDomain(domain);
c1.setPath("/");
} else {
c1.setDomain(domain);
c1.setPath("/cas/");
}
res.addCookie(c1);
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:
LOG.warning("Invalid response code (" + post.getStatusCode() + ") from CAS server!");
LOG.info("Response (1k): " + response.substring(0, Math.min(1024, response.length())));
break;
}
} catch (final IOException e) {
LOG.warning(e.getMessage());
} finally {
post.releaseConnection();
}
return null;
}
public static String getTicketGrantingTicket(final HttpServletResponse res,
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 201: {
final Matcher matcher = Pattern.compile(".*action=\".*/(.*?)\".*").matcher(response);
if (matcher.matches())
return matcher.group(1);
LOG.warning("Successful ticket granting request, but no ticket found!");
LOG.info("Response (1k): " + response.substring(0, Math.min(1024, response.length())));
break;
}
default:
LOG.warning("Invalid response code (" + post.getStatusCode() + ") from CAS server!");
LOG.info("Response (1k): " + response.substring(0, Math.min(1024, response.length())));
break;
}
}
catch (final IOException e) {
LOG.warning(e.getMessage());
}
finally {
post.releaseConnection();
}
return null;
}
private static void notNull(final Object object, final String message) {
if (object == null)
throw new IllegalArgumentException(message);
}
}

然后新建了一个servlet去调用上门这个类生成TICKET。

package com.feiquan16.cas.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.feiquan16.cas.util.CASUtility;
import com.feiquan16.cas.util.PropertiesReader;
public class CASTicketServlet extends HttpServlet {

/**
*
*/
private static final long serialVersionUID = 1L;
public static PropertiesReader pr = null;
public void doGet(HttpServletRequest request,HttpServletResponse response)throws ServletException, IOException{
PrintWriter writer = response.getWriter();
response.setContentType("text/html");

pr = PropertiesReader.getInstance("");
System.out.println("----------");
String server = pr.getPropertiy("cas.service.url");

String username = "b";request.getParameter("username");

String password = "b";request.getParameter("ObSSOCookie");
String service = "http://andrew.biz.com:9080/HRDemo";request.getParameter("service");

response.setHeader("P3P","CP=CAO PSA OUR");
System.out.println("----------");
String ticket = CASUtility.getTicket(request,response, server, username, password, service);

System.out.println(ticket);

response.sendRedirect(service);
writer.print(ticket);
}

public void doPost(HttpServletRequest request,HttpServletResponse response)throws ServletException, IOException{
this.doGet(request, response);
}

}

上面代码39行，将会跳转到应用HRDemo，这个HRDemo是被CAS保护的。

注意要模拟该场景至少需要2个web应用和一个cas服务端。这2个web应用中模拟生成ticket的应用不需要被CAS保护。另外，这个2个web应用需要在同一域中。

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