proxyticketreceptor.java

cas 客户端文件

/*
 *  Copyright (c) 2000-2003 Yale University. All rights reserved.
 *
 *  THIS SOFTWARE IS PROVIDED "AS IS," AND ANY EXPRESS OR IMPLIED
 *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE EXPRESSLY
 *  DISCLAIMED. IN NO EVENT SHALL YALE UNIVERSITY OR ITS EMPLOYEES BE
 *  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED, THE COSTS OF
 *  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA OR
 *  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 *  SOFTWARE, EVEN IF ADVISED IN ADVANCE OF THE POSSIBILITY OF SUCH
 *  DAMAGE.
 *
 *  Redistribution and use of this software in source or binary forms,
 *  with or without modification, are permitted, provided that the
 *  following conditions are met:
 *
 *  1. Any redistribution must include the above copyright notice and
 *  disclaimer and this list of conditions in any related documentation
 *  and, if feasible, in the redistributed software.
 *
 *  2. Any redistribution must include the acknowledgment, "This product
 *  includes software developed by Yale University," in any related
 *  documentation and, if feasible, in the redistributed software.
 *
 *  3. The names "Yale" and "Yale University" must not be used to endorse
 *  or promote products derived from this software.
 */

package edu.yale.its.tp.cas.proxy;

import java.io.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
import edu.yale.its.tp.cas.util.SecureURL;

/**
 * Receives and keeps track fo PGTs and serial PGT identifiers (IOUs) sent
 * by CAS in response to a ServiceValidate request.
 */
public class ProxyTicketReceptor extends HttpServlet {

	//*********************************************************************
	// Constants

	private static final String PGT_IOU_PARAM = "pgtIou";
	private static final String PGT_ID_PARAM = "pgtId";

	//*********************************************************************
	// Private state

	private static Map pgt;
	private static String casProxyUrl;

	//*********************************************************************
	// Initialization 

	public void init(ServletConfig config) throws ServletException {
		super.init(config);
		synchronized (ProxyTicketReceptor.class) {
			if (pgt == null)
				pgt = new HashMap();

			// retrieve the URL for CAS
			if (casProxyUrl == null) {
				ServletContext app = config.getServletContext();
				casProxyUrl =
					(String) app.getInitParameter("edu.yale.its.tp.cas.proxyUrl");
				if (casProxyUrl == null)
					throw new ServletException("need edu.yale.its.tp.cas.proxyUrl");
			}
		}
	}

	//*********************************************************************
	// Request handling

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

	public void doGet(HttpServletRequest request, HttpServletResponse response)
		throws ServletException, IOException {
		String pgtId = request.getParameter(PGT_ID_PARAM);
		String pgtIou = request.getParameter(PGT_IOU_PARAM);
		if (pgtId != null && pgtIou != null) {
			synchronized (pgt) {
				pgt.put(pgtIou, pgtId);
			}
		}
		PrintWriter out = response.getWriter();
		out.println(
			"<casClient:proxySuccess "
				+ "xmlns:casClient=\"http://www.yale.edu/tp/casClient\"/>");
		out.flush();
	}

	//*********************************************************************
	// Interface to package members

	// NOTE: PUBLIC FOR THE MOMENT

	/**
	 * Retrieves a proxy ticket using the PGT that corresponds to the given
	 * PGT IOU.
	 */
	public static String getProxyTicket(String pgtIou, String target)
		throws IOException {
		synchronized (ProxyTicketReceptor.class) {
			// ensure state is sensible
			if (casProxyUrl == null || pgt == null)
				throw new IllegalStateException("getProxyTicket() only works after servlet has been initialized");
		}

		// retrieve PGT
		String pgtId = null;
		synchronized (pgt) {
			pgtId = (String) pgt.get(pgtIou);
		}
		if (pgtId == null)
			return null;

		// retrieve an XML response from CAS's "Proxy" actuator
		String url = casProxyUrl + "?pgt=" + pgtId + "&targetService=" + target;
		String response = SecureURL.retrieve(url);

		// parse this response (use a lightweight approach for now)
		if (response.indexOf("<cas:proxySuccess>") != -1
			&& response.indexOf("<cas:proxyTicket>") != -1) {
			int startIndex =
				response.indexOf("<cas:proxyTicket>") + "<cas:proxyTicket>".length();
			int endIndex = response.indexOf("</cas:proxyTicket>");
			return response.substring(startIndex, endIndex);
		} else {
			// generic failure
			return null;
		}
	}
}