ResourceFilter.java

/* ===============================================================================
*
* Part of the InfoGlue Content Management Platform (www.infoglue.org)
*
* ===============================================================================
*
*  Copyright (C)
* 
* This program is free software; you can redistribute it and/or modify it under
* the terms of the GNU General Public License version 2, as published by the
* Free Software Foundation. See the file LICENSE.html for more information.
* 
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY, including the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
* 
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc. / 59 Temple
* Place, Suite 330 / Boston, MA 02111-1307 / USA.
*
* ===============================================================================
*/

package org.infoglue.deliver.applications.filters;

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 org.apache.log4j.Logger;
import org.infoglue.cms.util.CmsPropertyHandler;

/**
 * This filter adds expires headers on resources.
 * 
 * @author Mattias Bogeblad
 */

public class ResourceFilter implements Filter 
{
	public final static Logger logger = Logger.getLogger(ResourceFilter.class.getName());

	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException
	{
		HttpServletRequest req = (HttpServletRequest) request;
		HttpServletResponse resp = (HttpServletResponse) response;

		String requestURI = req.getRequestURI();
		if (CmsPropertyHandler.shouldTomcatGzipResources())
		{
			if (requestURI.indexOf(".png") > -1 || requestURI.indexOf(".jpg") > -1 || requestURI.indexOf(".gif") > -1)
			{
				if (logger.isTraceEnabled())
				{
					logger.trace("Found image resource. Checking for gzip support. URI: " + requestURI);
				}
				resp.setDateHeader("Expires", System.currentTimeMillis() + 365 * 24 * 60 * 60 * 1000);

				// check for the HTTP header that signifies GZIP support
				String ae = req.getHeader("accept-encoding");
				if (ae != null && ae.indexOf("gzip") != -1)
				{
					GZIPResponseWrapper wrappedResponse = new GZIPResponseWrapper(resp);
					chain.doFilter(request, wrappedResponse);
					wrappedResponse.finishResponse();
					return;
				}
			}
			else if (requestURI.indexOf(".js") > -1 || requestURI.indexOf(".css") > -1)
			{
				resp.setDateHeader("Expires", System.currentTimeMillis() + 1 * 24 * 60 * 60 * 1000);
			}
		}

		// Continue
		chain.doFilter(request, response);
	}

	public void destroy()
	{
	}

	public void init(FilterConfig arg0) throws ServletException
	{
	}
}