autologonfilter.java

一个功能较为完善的论坛

package org.redsoft.forum.filters;

import org.redsoft.forum.dao.DAOFactory;
import org.redsoft.forum.security.SimpleCallbackHandler;
import org.redsoft.forum.ForumConstants;
import org.redsoft.forum.exception.AccountNotFoundException;

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.Cookie;
import javax.security.auth.login.LoginContext;
import javax.security.auth.login.LoginException;
import javax.security.auth.Subject;
import java.io.IOException;
import java.sql.SQLException;

/**
 * <p>Filter that perform user auto logon
 *
 * Find username in cookies,and then perform auto logon
 *
 * @@author <a href="mailto:[e-mail]">cinc</a>
 *
 * @@version $Id: AutoLogonFilter.java,v 1.1.1.1 2003/07/08 08:25:16 cinc Exp $
 */

public class AutoLogonFilter implements Filter  {
    /**
     * Perform user auto logon
     *
     * Check session for user, if available, quit
     * Otherwise, check cookie for user, if available, proform auto login
     *      and save user to session
     *
     * @param request The servlet request we are processing
     * @param result The servlet response we are creating
     * @param chain The filter chain we are processing
     *
     * @exception IOException if an input/output error occurs
     * @exception ServletException if a servlet error occurs
     */
    public void doFilter(ServletRequest request, ServletResponse response,
                         FilterChain chain)
	throws IOException, ServletException {
        HttpServletRequest hreq = (HttpServletRequest)request;

        // find user info in session
        Subject subject
            =(Subject)hreq.getSession().getAttribute( ForumConstants.USER_KEY );

        // if subject is null, user is not loged in, check cookies
        if (subject == null){
            // check cookie
            Cookie[] cookies = hreq.getCookies();
            outputCookies(cookies);
            // find user in cookies
            String userName = findUserInCookie( cookies );
            System.out.println("username = " + userName );
            // if userName is not null, perform auto logon
            if ( userName != null ){
                String password = null;
                try {
                    password = DAOFactory.getInstance().getAccountDAO().findByUserName( userName ).getPassword();
                    LoginContext lc = new LoginContext("XForumLogin", new SimpleCallbackHandler( userName, password ) );
                    lc.login();
                    subject = lc.getSubject();
                    // save user info to session
                    hreq.getSession().setAttribute( ForumConstants.USER_KEY, subject );
                    System.out.println("Save user subject to session");
                } catch (SQLException e) {
                    e.printStackTrace();
                } catch (AccountNotFoundException e) {
                    e.printStackTrace();
                } catch (LoginException e) {
                    e.printStackTrace();
                }
            }
        }
        // Pass control on to the next filter
        chain.doFilter(request, response);
    }

    /**
     * Search for user in cookies
     *
     * @param cookies   the cookies
     * @return          if found, return username, otherwise return null
     */
    private String findUserInCookie( Cookie[] cookies ){
        if (cookies == null){
            return null;
        }
        for (int i = 0; i < cookies.length; i++) {
            Cookie cookie = cookies[i];
            if (cookie.getName().equals( ForumConstants.USER_KEY )){
                return cookie.getValue();
            }
        }
        return null;
    }

    /**
     * Output all cookies, for debug
     * @param cookies
     */
    private void outputCookies( Cookie[] cookies ) {
        if (cookies != null){
            System.out.println("Cookies:---------------------");
            for (int i = 0; i < cookies.length; i++) {
                Cookie c = cookies[i];
                String name = c.getName();
                String value = c.getValue();
                System.out.println(name + " = " + value);
            }
            System.out.println("Cookies:---------------------");
        }
    }

    /**
     * Place this filter into service.
     * Read acl configuration from file
     *
     * @param filterConfig The filter configuration object
     */
    public void init(FilterConfig filterConfig) throws ServletException {
    }

    /**
     * Take this filter out of service.
     */
    public void destroy() {
    }
}