gzipfilter.java

是离开的肌肤了卡机是离开的就富利卡及是了的开发及拉考试及的福利科技阿斯利康的肌肤莱卡及时的离开福建阿斯顿发

//========================================================================
//Copyright 2007 Mort Bay Consulting Pty. Ltd.
//------------------------------------------------------------------------
//Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
//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 org.mortbay.servlet;

import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.util.HashSet;
import java.util.Set;
import java.util.StringTokenizer;
import java.util.zip.GZIPOutputStream;

import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServletResponseWrapper;

import org.mortbay.util.ByteArrayOutputStream2;
import org.mortbay.util.StringUtil;

/* ------------------------------------------------------------ */
/** GZIP Filter
 * This filter will gzip the content of a response iff: <ul>
 * <li>The filter is mapped to a matching path</li>
 * <li>The response status code is >=200 and <300
 * <li>The content length is unknown or more than the <code>minGzipSize</code> initParameter or the minGzipSize is 0(default)</li>
 * <li>The content-type is in the coma separated list of mimeTypes set in the <code>mimeTypes</code> initParameter or
 * if no mimeTypes are defined the content-type is not "application/gzip"</li>
 * <li>No content-encoding is specified by the resource</li>
 * </ul>
 * 
 * <p>
 * Compressing the content can greatly improve the network bandwidth usage, but at a cost of memory and
 * CPU cycles.   If this filter is mapped for static content, then use of efficient direct NIO may be 
 * prevented, thus use of the gzip mechanism of the {@link org.mortbay.jetty.servlet.DefaultServlet} is 
 * advised instead.
 * </p>
 * <p>
 * This filter extends {@link UserAgentFilter} and if the the initParameter <code>excludedAgents</code> 
 * is set to a comma separated list of user agents, then these agents will be excluded from gzip content.
 * </p>
 *  
 * @author gregw
 *
 */
public class GzipFilter extends UserAgentFilter
{
    protected Set _mimeTypes;
    protected int _bufferSize=8192;
    protected int _minGzipSize=0;
    protected Set _excluded;
    
    public void init(FilterConfig filterConfig) throws ServletException
    {
        super.init(filterConfig);
        
        String tmp=filterConfig.getInitParameter("bufferSize");
        if (tmp!=null)
            _bufferSize=Integer.parseInt(tmp);

        tmp=filterConfig.getInitParameter("minGzipSize");
        if (tmp!=null)
            _minGzipSize=Integer.parseInt(tmp);
        
        tmp=filterConfig.getInitParameter("mimeTypes");
        if (tmp!=null)
        {
            _mimeTypes=new HashSet();
            StringTokenizer tok = new StringTokenizer(tmp,",",false);
            while (tok.hasMoreTokens())
                _mimeTypes.add(tok.nextToken());
        }
        
        tmp=filterConfig.getInitParameter("excludedAgents");
        if (tmp!=null)
        {
            _excluded=new HashSet();
            StringTokenizer tok = new StringTokenizer(tmp,",",false);
            while (tok.hasMoreTokens())
                _excluded.add(tok.nextToken());
        }
    }

    public void destroy()
    {
    }

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

        String ae = request.getHeader("accept-encoding");
        if (ae != null && ae.indexOf("gzip")>=0 && !response.containsHeader("Content-Encoding"))
        {
            if (_excluded!=null)
            {
                String ua=getUserAgent(request);
                if (_excluded.contains(ua))
                {
                    super.doFilter(request,response,chain);
                    return;
                }
            }

            GZIPResponseWrapper wrappedResponse=newGZIPResponseWrapper(request,response);
            
            boolean exceptional=true;
            try
            {
                super.doFilter(request,wrappedResponse,chain);
                exceptional=false;
            }
            finally
            {
                if (exceptional && !response.isCommitted())
                {
                    wrappedResponse.resetBuffer();
                    wrappedResponse.noGzip();
                }
                else
                    wrappedResponse.finish();
            }
        }
        else
        {
            super.doFilter(request,response,chain);
        }
    }
    
    protected GZIPResponseWrapper newGZIPResponseWrapper(HttpServletRequest request, HttpServletResponse response)
    {
        return new GZIPResponseWrapper(request,response);
    }


    public class GZIPResponseWrapper extends HttpServletResponseWrapper
    {
        HttpServletRequest _request;
        boolean _noGzip;
        PrintWriter _writer;
        GzipStream _gzStream;
        long _contentLength=-1;

        public GZIPResponseWrapper(HttpServletRequest request, HttpServletResponse response)
        {
            super(response);
            _request=request;
        }

        public void setContentType(String ct)
        {
            super.setContentType(ct);
            int colon=ct.indexOf(";");
            if (colon>0)
                ct=ct.substring(0,colon);

            if ((_gzStream==null || _gzStream._out==null) && 
                (_mimeTypes==null && "application/gzip".equalsIgnoreCase(ct) ||
                 _mimeTypes!=null && !_mimeTypes.contains(StringUtil.asciiToLowerCase(ct))))
            {
                noGzip();
            }
        }

        
        public void setStatus(int sc, String sm)
        {
            super.setStatus(sc,sm);
            if (sc<200||sc>=300)
                noGzip();
        }

        public void setStatus(int sc)
        {
            super.setStatus(sc);
            if (sc<200||sc>=300)
                noGzip();
        }

        public void setContentLength(int length)
        {
            _contentLength=length;
            if (_gzStream!=null)
                _gzStream.setContentLength(length);
        }
        
        public void addHeader(String name, String value)
        {
            if ("content-length".equalsIgnoreCase(name))
            {
                _contentLength=Long.parseLong(value);
                if (_gzStream!=null)
                    _gzStream.setContentLength(_contentLength);
            }
            else if ("content-type".equalsIgnoreCase(name))
            {   
                setContentType(value);
            }
            else if ("content-encoding".equalsIgnoreCase(name))
            {   
                super.addHeader(name,value);
                if (!isCommitted())
                {
                    noGzip();
                }
            }
            else
                super.addHeader(name,value);
        }
        
        public void setHeader(String name, String value)
        {
            if ("content-length".equalsIgnoreCase(name))
            {
                _contentLength=Long.parseLong(value);
                if (_gzStream!=null)
                    _gzStream.setContentLength(_contentLength);
            }
            else if ("content-type".equalsIgnoreCase(name))
            {   
                setContentType(value);
            }
            else if ("content-encoding".equalsIgnoreCase(name))
            {   
                super.setHeader(name,value);
                if (!isCommitted())
                {
                    noGzip();
                }
            }
            else
                super.setHeader(name,value);
        }

        public void setIntHeader(String name, int value)
        {
            if ("content-length".equalsIgnoreCase(name))
            {
                _contentLength=value;
                if (_gzStream!=null)
                    _gzStream.setContentLength(_contentLength);
            }
            else
                super.setIntHeader(name,value);
        }

        public void flushBuffer() throws IOException
        {
            if (_writer!=null)
                _writer.flush();
            if (_gzStream!=null)
                _gzStream.finish();
            else
                getResponse().flushBuffer();
        }

        public void reset()
        {
            super.reset();
            if (_gzStream!=null)
                _gzStream.resetBuffer();
            _writer=null;
            _gzStream=null;
            _noGzip=false;