zipfilter.java

CRM源码This file describes some issues that should be implemented in future and how it should be imple

/*
 * Copyright 2006-2007 Queplix Corp.
 *
 * Licensed under the Queplix Public License, Version 1.1.1 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.queplix.com/solutions/commercial-open-source/queplix-public-license/
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */

package com.queplix.core.modules.web.www;

import com.queplix.core.utils.www.AbstractFilter;
import com.queplix.core.utils.www.HSRWImpl;
import com.queplix.core.utils.www.ServletHelper;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.Enumeration;
import java.util.zip.GZIPOutputStream;

/**
 * <p>Gzip filter</p>
 * @author [ALB] Baranov Andrey
 * @version $Revision: 1.1.1.1 $ $Date: 2005/09/12 15:31:04 $
 */

public class ZipFilter
    extends AbstractFilter {

    /**
     * Make filter process
     * @param request Servlet request
     * @param response Servlet response
     * @param chain filter chain object
     * @exception IOException General input/output exception
     * @exception ServletException General servlet exception
     */
    public void doFilter( ServletRequest request,
                          ServletResponse response,
                          FilterChain chain )
        throws IOException, ServletException {

        HttpServletRequest req = ( HttpServletRequest ) request;
        HttpServletResponse res = ( HttpServletResponse ) response;

        boolean isGzip = isGZipSupported( req );
        boolean isDebugEnabled = logger.getLogger().isDebugEnabled();

        if( isDebugEnabled ) {
            logger.DEBUG( "ZipFilter" );
            logger.DEBUG( "  request from: " + req.getRequestURI() );
            logger.DEBUG( "  is gzip supported: " + isGzip );
        }

        if( isGzip ) {
            res.setHeader( "Content-Encoding", ServletHelper.CONTENT_TYPE_GZIP );
            GZIPOutputStream gzos = new GZIPOutputStream( res.getOutputStream(), HSRWImpl.BUFFER_SIZE );

            HSRWImpl hsrw = new HSRWImpl( res, gzos );
            chain.doFilter( req, hsrw );

            hsrw.flush();
            gzos.close();

        } else {
            chain.doFilter( req, res );
        }
    }

    /**
     * Detect if request supports GZipping.
     * @param req HttpServletRequest object
     * @return true of false
     */
    public static boolean isGZipSupported( HttpServletRequest req ) {
        boolean isGzip = false;

        if( req.getProtocol().equalsIgnoreCase( "HTTP/1.1" ) &&
            !req.getRemoteAddr().equals( "127.0.0.1" ) ) {
            Enumeration e = req.getHeaders( "Accept-Encoding" );
            if( e != null ) {
                while( e.hasMoreElements() ) {
                    String name = ( String ) e.nextElement();
                    if( name.indexOf( "gzip" ) >= 0 ) {
                        isGzip = true;
                        break;
                    }
                }
            }
        }

        return isGzip;

    }
}