package de.intevation.flys.client.server;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.apache.log4j.Logger;

import de.intevation.flys.client.server.auth.User;


/** ServletFilter used for GGInA authentification and certain authorisation. */
public class GGInAFilter implements Filter {

    /** Private logger. */
    private static Logger logger = Logger.getLogger(GGInAFilter.class);

    private boolean deactivate = false;


    /**
     * Initialize.
     *
     * Read FilterConfig parameter deactivate
     */
    @Override
    public void init(FilterConfig config)
    throws ServletException
    {
        String deactivate = config.getInitParameter("deactivate");
        if (deactivate != null && deactivate.equalsIgnoreCase("true")) {
            this.deactivate = true;
        }

    }


    /**
     * Called when filter in chain invoked.
     * @param req request to servlet
     * @param resp response of servlet
     * @param chain the filter chain
     */
    @Override
    public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain)
    throws IOException, ServletException
    {
        if (this.deactivate) {
            logger.debug("GGinAFilter is deactivated");
            chain.doFilter(req, resp);
            return;
        }

        HttpServletRequest sreq = (HttpServletRequest) req;

        String requesturi = sreq.getRequestURI();

        logger.debug("Request for: " + requesturi);

        // Allow access to login pages
        // TODO Maybe replace with Filter <url-pattern>
        if (requesturi.equals("/login.jsp") || requesturi.equals("/flys/login")
                || requesturi.equals("/FLYS.css")) {
            logger.debug("Request for login " + requesturi);
            chain.doFilter(req, resp);
            return;
        }

        HttpSession session = sreq.getSession();

        String uri = requesturi;
        if (sreq.getQueryString() != null) {
            uri = uri + "?" + sreq.getQueryString();
        }
        session.setAttribute("requesturi", uri);

        User user = (User)session.getAttribute("user");
        if (user == null) {
            logger.debug("No user in session: " + requesturi);
            this.redirect(resp);
            return;
        }
        if (user.hasExpired()) {
            logger.debug("User ticket has expired: " + requesturi);
            this.redirect(resp);
            return;
        }

        logger.debug("GGInAFilter.doFilter");
        chain.doFilter(req, resp);
        return;
    }

    private void redirect(ServletResponse resp) throws IOException {
        logger.debug("Redirect to login");
        ((HttpServletResponse) resp).sendRedirect("/login.jsp");
    }


    /**
     * Do nothing at destruction.
     */
    @Override
    public void destroy() {
    }
}
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