teichmann@5835: package org.dive4elements.river.client.server.filter;
bjoern@4423: 
bjoern@4423: import java.io.IOException;
bjoern@4423: import java.util.Date;
bjoern@4423: 
bjoern@4423: import javax.servlet.Filter;
bjoern@4423: import javax.servlet.FilterChain;
bjoern@4423: import javax.servlet.FilterConfig;
bjoern@4423: import javax.servlet.ServletException;
bjoern@4423: import javax.servlet.ServletRequest;
bjoern@4423: import javax.servlet.ServletResponse;
bjoern@4423: import javax.servlet.http.HttpServletRequest;
bjoern@4423: import javax.servlet.http.HttpServletResponse;
bjoern@4423: 
bjoern@4423: import org.apache.log4j.Logger;
bjoern@4423: 
bjoern@4423: /** ServletFilter to avoid caching for GWTs *.nocache.* files. */
bjoern@4423: public class NoCacheFilter implements Filter {
bjoern@4423: 
bjoern@4423:     private static final long DAY = 86400000L;
bjoern@4423: 
bjoern@4423:     private static final String NO_CACHE = ".nocache.";
bjoern@4423: 
bjoern@4423:     private static Logger log = Logger.getLogger(NoCacheFilter.class);
bjoern@4423: 
bjoern@4423:     /**
bjoern@4423:      * Initialize.
bjoern@4423:      */
bjoern@4423:     @Override
bjoern@4423:     public void init(FilterConfig config)
bjoern@4423:     throws ServletException
bjoern@4423:     {
bjoern@4423:     }
bjoern@4423: 
bjoern@4423: 
bjoern@4423:     /**
bjoern@4423:      * Called when filter in chain invoked.
bjoern@4423:      * @param req request to servlet
bjoern@4423:      * @param resp response of servlet
bjoern@4423:      * @param chain the filter chain
bjoern@4423:      */
bjoern@4423:     @Override
bjoern@4423:     public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain)
bjoern@4423:     throws IOException, ServletException
bjoern@4423:     {
bjoern@4423:         HttpServletRequest httpreq = (HttpServletRequest)req;
bjoern@4423:         String uri = httpreq.getRequestURI();
bjoern@4423: 
bjoern@4423:         if (uri.contains(NO_CACHE)) {
bjoern@4423:             log.debug("Set no-cache for " + uri);
bjoern@4423: 
bjoern@4423:             Date now = new Date();
bjoern@4423:             HttpServletResponse httpresp = (HttpServletResponse)resp;
bjoern@4423:             httpresp.setDateHeader("Date", now.getTime());
bjoern@4423:             httpresp.setDateHeader("Expires", now.getTime() - DAY);
bjoern@4423:             httpresp.setHeader("Pragma", "no-cache");
bjoern@4423:             httpresp.setHeader("Cache-control",
bjoern@4423:                     "no-cache, no-store, must-revalidate");
bjoern@4423:         }
bjoern@4423: 
bjoern@4423:         chain.doFilter(req, resp);
bjoern@4423:     }
bjoern@4423: 
bjoern@4423: 
bjoern@4423:     /**
bjoern@4423:      * Do nothing at destruction.
bjoern@4423:      */
bjoern@4423:     @Override
bjoern@4423:     public void destroy() {
bjoern@4423:     }
bjoern@4423: }
bjoern@4423: // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :