//========================================================================
//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.io.UnsupportedEncodingException;
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 comma 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");
Boolean gzip=(Boolean)request.getAttribute("GzipFilter");
if (ae != null && ae.indexOf("gzip")>=0 && !response.containsHeader("Content-Encoding") &&
(gzip==null || gzip.booleanValue()) && !"HEAD".equalsIgnoreCase(request.getMethod()))
{
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;
}
catch(RuntimeException e)
{
request.setAttribute("GzipFilter",Boolean.FALSE);
if (!response.isCommitted())
response.reset();
throw e;
}
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);
}
/*
* Allows derived implementations to replace PrintWriter implementation
*/
protected PrintWriter newWriter(OutputStream out,String encoding) throws UnsupportedEncodingException
{
return encoding==null?new PrintWriter(out):new PrintWriter(new OutputStreamWriter(out,encoding));
}
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);
if (ct!=null)
{
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 && (ct==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;
_contentLength=-1;
}
public void resetBuffer()
{
super.resetBuffer();
if (_gzStream!=null)
_gzStream.resetBuffer();
_writer=null;
_gzStream=null;
}
public void sendError(int sc, String msg) throws IOException
{
resetBuffer();
super.sendError(sc,msg);
}
public void sendError(int sc) throws IOException
{
resetBuffer();
super.sendError(sc);
}
public void sendRedirect(String location) throws IOException
{
resetBuffer();
super.sendRedirect(location);
}
public ServletOutputStream getOutputStream() throws IOException
{
if (_gzStream==null)
{
if (getResponse().isCommitted() || _noGzip)
return getResponse().getOutputStream();
_gzStream=newGzipStream(_request,(HttpServletResponse)getResponse(),_contentLength,_bufferSize,_minGzipSize);
}
else if (_writer!=null)
throw new IllegalStateException("getWriter() called");
return _gzStream;
}
public PrintWriter getWriter() throws IOException
{
if (_writer==null)
{
if (_gzStream!=null)
throw new IllegalStateException("getOutputStream() called");
if (getResponse().isCommitted() || _noGzip)
return getResponse().getWriter();
_gzStream=newGzipStream(_request,(HttpServletResponse)getResponse(),_contentLength,_bufferSize,_minGzipSize);
_writer=newWriter(_gzStream,getCharacterEncoding());
}
return _writer;
}
void noGzip()
{
_noGzip=true;
if (_gzStream!=null)
{
try
{
_gzStream.doNotGzip();
}
catch (IOException e)
{
throw new IllegalStateException();
}
}
}
void finish() throws IOException
{
if (_writer!=null && !_gzStream._closed)
_writer.flush();
if (_gzStream!=null)
_gzStream.finish();
}
protected GzipStream newGzipStream(HttpServletRequest request,HttpServletResponse response,long contentLength,int bufferSize, int minGzipSize) throws IOException
{
return new GzipStream(request,response,contentLength,bufferSize,minGzipSize);
}
}
public static class GzipStream extends ServletOutputStream
{
protected HttpServletRequest _request;
protected HttpServletResponse _response;
protected OutputStream _out;
protected ByteArrayOutputStream2 _bOut;
protected GZIPOutputStream _gzOut;
protected boolean _closed;
protected int _bufferSize;
protected int _minGzipSize;
protected long _contentLength;
public GzipStream(HttpServletRequest request,HttpServletResponse response,long contentLength,int bufferSize, int minGzipSize) throws IOException
{
_request=request;
_response=response;
_contentLength=contentLength;
_bufferSize=bufferSize;
_minGzipSize=minGzipSize;
if (minGzipSize==0)
doGzip();
}
public void resetBuffer()
{
_closed=false;
_out=null;
_bOut=null;
if (_gzOut!=null && !_response.isCommitted())
_response.setHeader("Content-Encoding",null);
_gzOut=null;
}
public void setContentLength(long length)
{
_contentLength=length;
}
public void flush() throws IOException
{
if (_out==null || _bOut!=null)
{
if (_contentLength>0 && _contentLength<_minGzipSize)
doNotGzip();
else
doGzip();
}
_out.flush();
}
public void close() throws IOException
{
if (_request.getAttribute("javax.servlet.include.request_uri")!=null)
flush();
else
{
if (_bOut!=null)
{
if (_contentLength<0)
_contentLength=_bOut.getCount();
if (_contentLength<_minGzipSize)
doNotGzip();
else
doGzip();
}
else if (_out==null)
{
doNotGzip();
}
if (_gzOut!=null)
_gzOut.finish();
_out.close();
_closed=true;
}
}
public void finish() throws IOException
{
if (!_closed)
{
if (_out==null || _bOut!=null)
{
if (_contentLength>0 && _contentLength<_minGzipSize)
doNotGzip();
else
doGzip();
}
if (_gzOut!=null)
_gzOut.finish();
}
}
public void write(int b) throws IOException
{
checkOut(1);
_out.write(b);
}
public void write(byte b[]) throws IOException
{
checkOut(b.length);
_out.write(b);
}
public void write(byte b[], int off, int len) throws IOException
{
checkOut(len);
_out.write(b,off,len);
}
protected boolean setContentEncodingGzip()
{
_response.setHeader("Content-Encoding", "gzip");
return _response.containsHeader("Content-Encoding");
}
public void doGzip() throws IOException
{
if (_gzOut==null)
{
if (_response.isCommitted())
throw new IllegalStateException();
if (setContentEncodingGzip())
{
_out=_gzOut=new GZIPOutputStream(_response.getOutputStream(),_bufferSize);
if (_bOut!=null)
{
_out.write(_bOut.getBuf(),0,_bOut.getCount());
_bOut=null;
}
}
else
doNotGzip();
}
}
public void doNotGzip() throws IOException
{
if (_gzOut!=null)
throw new IllegalStateException();
if (_out==null || _bOut!=null )
{
_out=_response.getOutputStream();
if (_contentLength>=0)
{
if(_contentLength<Integer.MAX_VALUE)
_response.setContentLength((int)_contentLength);
else
_response.setHeader("Content-Length",Long.toString(_contentLength));
}
if (_bOut!=null)
_out.write(_bOut.getBuf(),0,_bOut.getCount());
_bOut=null;
}
}
private void checkOut(int length) throws IOException
{
if (_closed)
{
new Throwable().printStackTrace();
throw new IOException("CLOSED");
}
if (_out==null)
{
if (_response.isCommitted() || (_contentLength>=0 && _contentLength<_minGzipSize))
doNotGzip();
else if (length>_minGzipSize)
doGzip();
else
_out=_bOut=new ByteArrayOutputStream2(_bufferSize);
}
else if (_bOut!=null)
{
if (_response.isCommitted() || (_contentLength>=0 && _contentLength<_minGzipSize))
doNotGzip();
else if (length>=(_bOut.getBuf().length-_bOut.getCount()))
doGzip();
}
}
}
}