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// ========================================================================
// Copyright (c) 2007-2009 Mort Bay Consulting Pty. Ltd.
// ------------------------------------------------------------------------
// All rights reserved. This program and the accompanying materials
// are made available under the terms of the Eclipse Public License v1.0
// and Apache License v2.0 which accompanies this distribution.
// The Eclipse Public License is available at
// http://www.eclipse.org/legal/epl-v10.html
// The Apache License v2.0 is available at
// http://www.opensource.org/licenses/apache2.0.php
// You may elect to redistribute this code under either of these licenses.
// ========================================================================
package org.eclipse.jetty.servlets;
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 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.eclipse.jetty.continuation.Continuation;
import org.eclipse.jetty.continuation.ContinuationListener;
import org.eclipse.jetty.continuation.ContinuationSupport;
import org.eclipse.jetty.http.HttpMethods;
import org.eclipse.jetty.http.gzip.GzipResponseWrapper;
import org.eclipse.jetty.util.log.Log;
/* ------------------------------------------------------------ */
/** 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.eclipse.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>
*
*/
public class GzipFilter extends UserAgentFilter
{
protected Set<String> _mimeTypes;
protected int _bufferSize=8192;
protected int _minGzipSize=256;
protected Set<String> _excluded;
/* ------------------------------------------------------------ */
/**
* @see org.eclipse.jetty.servlets.UserAgentFilter#init(javax.servlet.FilterConfig)
*/
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<String>();
StringTokenizer tok = new StringTokenizer(tmp,",",false);
while (tok.hasMoreTokens())
_mimeTypes.add(tok.nextToken());
}
tmp=filterConfig.getInitParameter("excludedAgents");
if (tmp!=null)
{
_excluded=new HashSet<String>();
StringTokenizer tok = new StringTokenizer(tmp,",",false);
while (tok.hasMoreTokens())
_excluded.add(tok.nextToken());
}
}
/* ------------------------------------------------------------ */
/**
* @see org.eclipse.jetty.servlets.UserAgentFilter#destroy()
*/
public void destroy()
{
}
/* ------------------------------------------------------------ */
/**
* @see org.eclipse.jetty.servlets.UserAgentFilter#doFilter(javax.servlet.ServletRequest, javax.servlet.ServletResponse, javax.servlet.FilterChain)
*/
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")
&& !HttpMethods.HEAD.equalsIgnoreCase(request.getMethod()))
{
if (_excluded!=null)
{
String ua=getUserAgent(request);
if (_excluded.contains(ua))
{
super.doFilter(request,response,chain);
return;
}
}
final GzipResponseWrapper wrappedResponse=newGzipResponseWrapper(request,response);
boolean exceptional=true;
try
{
super.doFilter(request,wrappedResponse,chain);
exceptional=false;
}
finally
{
Continuation continuation = ContinuationSupport.getContinuation(request);
if (continuation.isSuspended() && continuation.isResponseWrapped())
{
continuation.addContinuationListener(new ContinuationListener()
{
public void onComplete(Continuation continuation)
{
try
{
wrappedResponse.finish();
}
catch(IOException e)
{
Log.warn(e);
}
}
public void onTimeout(Continuation continuation)
{}
});
}
else if (exceptional && !response.isCommitted())
{
wrappedResponse.resetBuffer();
wrappedResponse.noGzip();
}
else
wrappedResponse.finish();
}
}
else
{
super.doFilter(request,response,chain);
}
}
/**
* Allows derived implementations to replace ResponseWrapper implementation.
*
* @param request the request
* @param response the response
* @return the gzip response wrapper
*/
protected GzipResponseWrapper newGzipResponseWrapper(HttpServletRequest request, HttpServletResponse response)
{
return new GzipResponseWrapper(request, response)
{
{
_mimeTypes = GzipFilter.this._mimeTypes;
_bufferSize = GzipFilter.this._bufferSize;
_minGzipSize = GzipFilter.this._minGzipSize;
}
@Override
protected PrintWriter newWriter(OutputStream out,String encoding) throws UnsupportedEncodingException
{
return GzipFilter.this.newWriter(out,encoding);
}
};
}
/**
* Allows derived implementations to replace PrintWriter implementation.
*
* @param out the out
* @param encoding the encoding
* @return the prints the writer
* @throws UnsupportedEncodingException
*/
protected PrintWriter newWriter(OutputStream out,String encoding) throws UnsupportedEncodingException
{
return encoding==null?new PrintWriter(out):new PrintWriter(new OutputStreamWriter(out,encoding));
}
}
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