org.eclipse.jetty.servlets.GzipFilter Maven / Gradle / Ivy
//
// ========================================================================
// Copyright (c) 1995-2013 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.util.HashSet;
import java.util.Locale;
import java.util.Set;
import java.util.StringTokenizer;
import java.util.regex.Pattern;
import java.util.zip.Deflater;
import java.util.zip.DeflaterOutputStream;
import java.util.zip.GZIPOutputStream;
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.ServletResponseWrapper;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServletResponseWrapper;
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.CompressedResponseWrapper;
import org.eclipse.jetty.http.gzip.AbstractCompressedStream;
import org.eclipse.jetty.util.StringUtil;
import org.eclipse.jetty.util.log.Log;
import org.eclipse.jetty.util.log.Logger;
/* ------------------------------------------------------------ */
/** GZIP Filter
* This filter will gzip or deflate the content of a response if:
* - The filter is mapped to a matching path
* - accept-encoding header is set to either gzip, deflate or a combination of those
* - The response status code is >=200 and <300
*
- The content length is unknown or more than the
minGzipSize initParameter or the minGzipSize is 0(default)
* - The content-type is in the comma separated list of mimeTypes set in the
mimeTypes initParameter or
* if no mimeTypes are defined the content-type is not "application/gzip"
* - No content-encoding is specified by the resource
*
*
*
* If both gzip and deflate are specified in the accept-encoding header, then gzip will be used.
*
*
* 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.
*
*
* This filter extends {@link UserAgentFilter} and if the the initParameter excludedAgents
* is set to a comma separated list of user agents, then these agents will be excluded from gzip content.
*
* Init Parameters:
*
* bufferSize The output buffer size. Defaults to 8192. Be careful as values <= 0 will lead to an
* {@link IllegalArgumentException}.
* See: {@link java.util.zip.GZIPOutputStream#GZIPOutputStream(java.io.OutputStream, int)}
* and: {@link java.util.zip.DeflaterOutputStream#DeflaterOutputStream(java.io.OutputStream, Deflater, int)}
*
* minGzipSize Content will only be compressed if content length is either unknown or greater
* than minGzipSize.
*
* deflateCompressionLevel The compression level used for deflate compression. (0-9).
* See: {@link java.util.zip.Deflater#Deflater(int, boolean)}
*
* deflateNoWrap The noWrap setting for deflate compression. Defaults to true. (true/false)
* See: {@link java.util.zip.Deflater#Deflater(int, boolean)}
*
* mimeTypes Comma separated list of mime types to compress. See description above.
*
* excludedAgents Comma separated list of user agents to exclude from compression. Does a
* {@link String#contains(CharSequence)} to check if the excluded agent occurs
* in the user-agent header. If it does -> no compression
*
* excludeAgentPatterns Same as excludedAgents, but accepts regex patterns for more complex matching.
*
* excludePaths Comma separated list of paths to exclude from compression.
* Does a {@link String#startsWith(String)} comparison to check if the path matches.
* If it does match -> no compression. To match subpaths use excludePathPatterns
* instead.
*
* excludePathPatterns Same as excludePath, but accepts regex patterns for more complex matching.
*
* vary Set to the value of the Vary header sent with responses that could be compressed. By default it is
* set to 'Vary: Accept-Encoding, User-Agent' since IE6 is excluded by default from the excludedAgents.
* If user-agents are not to be excluded, then this can be set to 'Vary: Accept-Encoding'. Note also
* that shared caches may cache copies of a resource that is varied by User-Agent - one per variation of
* the User-Agent, unless the cache does some normalization of the UA string.
*
*/
public class GzipFilter extends UserAgentFilter
{
private static final Logger LOG = Log.getLogger(GzipFilter.class);
public final static String GZIP="gzip";
public final static String ETAG_GZIP="--gzip\"";
public final static String DEFLATE="deflate";
public final static String ETAG_DEFLATE="--deflate\"";
public final static String ETAG="o.e.j.s.GzipFilter.ETag";
protected ServletContext _context;
protected Set _mimeTypes;
protected int _bufferSize=8192;
protected int _minGzipSize=256;
protected int _deflateCompressionLevel=Deflater.DEFAULT_COMPRESSION;
protected boolean _deflateNoWrap = true;
protected Set _excludedAgents;
protected Set _excludedAgentPatterns;
protected Set _excludedPaths;
protected Set _excludedPathPatterns;
protected String _vary="Accept-Encoding, User-Agent";
private static final int STATE_SEPARATOR = 0;
private static final int STATE_Q = 1;
private static final int STATE_QVALUE = 2;
private static final int STATE_DEFAULT = 3;
/* ------------------------------------------------------------ */
/**
* @see org.eclipse.jetty.servlets.UserAgentFilter#init(javax.servlet.FilterConfig)
*/
@Override
public void init(FilterConfig filterConfig) throws ServletException
{
super.init(filterConfig);
_context=filterConfig.getServletContext();
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("deflateCompressionLevel");
if (tmp!=null)
_deflateCompressionLevel=Integer.parseInt(tmp);
tmp=filterConfig.getInitParameter("deflateNoWrap");
if (tmp!=null)
_deflateNoWrap=Boolean.parseBoolean(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)
{
_excludedAgents=new HashSet();
StringTokenizer tok = new StringTokenizer(tmp,",",false);
while (tok.hasMoreTokens())
_excludedAgents.add(tok.nextToken());
}
tmp=filterConfig.getInitParameter("excludeAgentPatterns");
if (tmp!=null)
{
_excludedAgentPatterns=new HashSet();
StringTokenizer tok = new StringTokenizer(tmp,",",false);
while (tok.hasMoreTokens())
_excludedAgentPatterns.add(Pattern.compile(tok.nextToken()));
}
tmp=filterConfig.getInitParameter("excludePaths");
if (tmp!=null)
{
_excludedPaths=new HashSet();
StringTokenizer tok = new StringTokenizer(tmp,",",false);
while (tok.hasMoreTokens())
_excludedPaths.add(tok.nextToken());
}
tmp=filterConfig.getInitParameter("excludePathPatterns");
if (tmp!=null)
{
_excludedPathPatterns=new HashSet();
StringTokenizer tok = new StringTokenizer(tmp,",",false);
while (tok.hasMoreTokens())
_excludedPathPatterns.add(Pattern.compile(tok.nextToken()));
}
tmp=filterConfig.getInitParameter("vary");
if (tmp!=null)
_vary=tmp;
}
/* ------------------------------------------------------------ */
/**
* @see org.eclipse.jetty.servlets.UserAgentFilter#destroy()
*/
@Override
public void destroy()
{
}
/* ------------------------------------------------------------ */
/**
* @see org.eclipse.jetty.servlets.UserAgentFilter#doFilter(javax.servlet.ServletRequest, javax.servlet.ServletResponse, javax.servlet.FilterChain)
*/
@Override
public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain)
throws IOException, ServletException
{
HttpServletRequest request=(HttpServletRequest)req;
HttpServletResponse response=(HttpServletResponse)res;
// If not a GET or an Excluded URI - no Vary because no matter what client, this URI is always excluded
String requestURI = request.getRequestURI();
if (!HttpMethods.GET.equalsIgnoreCase(request.getMethod()) || isExcludedPath(requestURI))
{
super.doFilter(request,response,chain);
return;
}
// Exclude non compressible mime-types known from URI extension. - no Vary because no matter what client, this URI is always excluded
if (_mimeTypes!=null && _mimeTypes.size()>0)
{
String mimeType = _context.getMimeType(request.getRequestURI());
if (mimeType!=null && !_mimeTypes.contains(mimeType))
{
// handle normally without setting vary header
super.doFilter(request,response,chain);
return;
}
}
// Excluded User-Agents
String ua = getUserAgent(request);
boolean ua_excluded=ua!=null&&isExcludedAgent(ua);
// Acceptable compression type
String compressionType = ua_excluded?null:selectCompression(request.getHeader("accept-encoding"));
// Special handling for etags
String etag = request.getHeader("If-None-Match");
if (etag!=null)
{
int dd=etag.indexOf("--");
if (dd>0)
request.setAttribute(ETAG,etag.substring(0,dd)+(etag.endsWith("\"")?"\"":""));
}
CompressedResponseWrapper wrappedResponse = createWrappedResponse(request,response,compressionType);
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 ContinuationListenerWaitingForWrappedResponseToFinish(wrappedResponse));
}
else if (exceptional && !response.isCommitted())
{
wrappedResponse.resetBuffer();
wrappedResponse.noCompression();
}
else
wrappedResponse.finish();
}
}
/* ------------------------------------------------------------ */
private String selectCompression(String encodingHeader)
{
// TODO, this could be a little more robust.
// prefer gzip over deflate
String compression = null;
if (encodingHeader!=null)
{
String[] encodings = getEncodings(encodingHeader);
if (encodings != null)
{
for (int i=0; i< encodings.length; i++)
{
if (encodings[i].toLowerCase(Locale.ENGLISH).contains(GZIP))
{
if (isEncodingAcceptable(encodings[i]))
{
compression = GZIP;
break; //prefer Gzip over deflate
}
}
if (encodings[i].toLowerCase(Locale.ENGLISH).contains(DEFLATE))
{
if (isEncodingAcceptable(encodings[i]))
{
compression = DEFLATE; //Keep checking in case gzip is acceptable
}
}
}
}
}
return compression;
}
private String[] getEncodings (String encodingHeader)
{
if (encodingHeader == null)
return null;
return encodingHeader.split(",");
}
private boolean isEncodingAcceptable(String encoding)
{
int state = STATE_DEFAULT;
int qvalueIdx = -1;
for (int i=0;i