PlutoResourceFilter.java

/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2012, Red Hat, Inc., and individual contributors
 * as indicated by the @author tags. See the copyright.txt file in the
 * distribution for a full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.jboss.portletbridge.test;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URL;
import java.util.Calendar;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class PlutoResourceFilter implements Filter {

    private ServletContext servletContext;

    private final static Calendar LAST_MODIFIED = Calendar.getInstance();

    public void destroy() {
    }

    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException,
            ServletException {
        if (request instanceof HttpServletRequest && response instanceof HttpServletResponse) {
            HttpServletRequest httpServletRequest = (HttpServletRequest) request;
            HttpServletResponse httpServletResponse = (HttpServletResponse) response;
            String resource = httpServletRequest.getServletPath();
            if (resource == null) {
                resource = httpServletRequest.getPathInfo();
            }
            URL resourceUrl = servletContext.getResource(resource);
            if (resourceUrl == null) {
                // Serve resource from classpath
                resourceUrl = Thread.currentThread().getContextClassLoader().getResource(resource);
                if (resourceUrl == null && resource.startsWith("/")) {
                    resourceUrl = Thread.currentThread().getContextClassLoader().getResource(resource.substring(1));
                }
                if (resourceUrl == null) {
                    chain.doFilter(request, response);
                } else {
                    Calendar cal = Calendar.getInstance();

                    // check for if-modified-since, prior to any other headers
                    long ifModifiedSince = 0;
                    try {
                        ifModifiedSince = httpServletRequest.getDateHeader("If-Modified-Since");
                    } catch (Exception e) {

                    }
                    long lastModifiedMillis = LAST_MODIFIED.getTimeInMillis();
                    long now = cal.getTimeInMillis();
                    cal.add(Calendar.DAY_OF_MONTH, 1);
                    long expires = cal.getTimeInMillis();

                    if (ifModifiedSince > 0 && ifModifiedSince <= lastModifiedMillis) {
                        // not modified, content is not sent - only basic
                        // headers and status SC_NOT_MODIFIED
                        httpServletResponse.setDateHeader("Expires", expires);
                        httpServletResponse.setStatus(HttpServletResponse.SC_NOT_MODIFIED);
                    } else {
                        httpServletResponse.setDateHeader("Date", now);
                        httpServletResponse.setDateHeader("Expires", expires);
                        httpServletResponse.setDateHeader("Retry-After", expires);
                        httpServletResponse.setHeader("Cache-Control", "public");
                        httpServletResponse.setDateHeader("Last-Modified", lastModifiedMillis);
                        InputStream stream = resourceUrl.openStream();
                        OutputStream out = response.getOutputStream();
                        try {
                            int read = stream.read();
                            while (read != -1) {
                                out.write(read);
                                read = stream.read();
                            }
                        } finally {
                            stream.close();
                        }
                    }
                }
            } else {
                chain.doFilter(request, response);
            }
        } else {
            chain.doFilter(request, response);
        }
    }

    public void init(FilterConfig filterconfig) throws ServletException {
        this.servletContext = filterconfig.getServletContext();
    }

}