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/*
* CompressionFilter.java
* $Header: /home/cvs/jakarta-tomcat-4.0/webapps/examples/WEB-INF/classes/compressionFilters/CompressionFilter.java,v 1.8 2002/07/16 17:19:13 amyroh Exp $
* $Revision: 1.8 $
* $Date: 2002/07/16 17:19:13 $
*
* ====================================================================
*
* The Apache Software License, Version 1.1
*
* Copyright (c) 1999 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowlegement:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowlegement may appear in the software itself,
* if and wherever such third-party acknowlegements normally appear.
*
* 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
* Foundation" must not be used to endorse or promote products derived
* from this software without prior written permission. For written
* permission, please contact
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*
* 5. Products derived from this software may not be called "Apache"
* nor may "Apache" appear in their names without prior written
* permission of the Apache Group.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
* [Additional notices, if required by prior licensing conditions]
*
*/
package jaoso.framework.web.filter.compression;
import java.io.IOException;
import java.util.Enumeration;
import javax.servlet.Filter;
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;
/**
* Implementation of <code>javax.servlet.Filter</code> used to compress
* the ServletResponse if it is bigger than a threshold.
*
* @author Amy Roh
* @author Dmitri Valdin
* @version $Revision: 1.8 $, $Date: 2002/07/16 17:19:13 $
*/
public class CompressionFilter implements Filter{
/**
* The filter configuration object we are associated with. If this value
* is null, this filter instance is not currently configured.
*/
private FilterConfig config = null;
/**
* Minimal reasonable threshold
*/
private int minThreshold = 128;
/**
* The threshold number to compress
*/
protected int compressionThreshold;
/**
* Debug level for this filter
*/
private int debug = 0;
/**
* Place this filter into service.
*
* @param filterConfig The filter configuration object
*/
public void init(FilterConfig filterConfig) {
config = filterConfig;
if (filterConfig != null) {
String value = filterConfig.getInitParameter("debug");
if (value!=null) {
debug = Integer.parseInt(value);
} else {
debug = 0;
}
String str = filterConfig.getInitParameter("compressionThreshold");
if (str!=null) {
compressionThreshold = Integer.parseInt(str);
if (compressionThreshold != 0 && compressionThreshold < minThreshold) {
if (debug > 0) {
System.out.println("compressionThreshold should be either 0 - no compression or >= " + minThreshold);
System.out.println("compressionThreshold set to " + minThreshold);
}
compressionThreshold = minThreshold;
}
} else {
compressionThreshold = 0;
}
} else {
compressionThreshold = 0;
}
}
/**
* Take this filter out of service.
*/
public void destroy() {
this.config = null;
}
/**
* The <code>doFilter</code> method of the Filter is called by the container
* each time a request/response pair is passed through the chain due
* to a client request for a resource at the end of the chain.
* The FilterChain passed into this method allows the Filter to pass on the
* request and response to the next entity in the chain.<p>
* This method first examines the request to check whether the client support
* compression. <br>
* It simply just pass the request and response if there is no support for
* compression.<br>
* If the compression support is available, it creates a
* CompressionServletResponseWrapper object which compresses the content and
* modifies the header if the content length is big enough.
* It then invokes the next entity in the chain using the FilterChain object
* (<code>chain.doFilter()</code>), <br>
**/
public void doFilter ( ServletRequest request, ServletResponse response,
FilterChain chain ) throws IOException, ServletException {
if (debug > 0) {
System.out.println("@doFilter");
}
if (compressionThreshold == 0) {
if (debug > 0) {
System.out.println("doFilter gets called, but compressionTreshold is set to 0 - no compression");
}
chain.doFilter(request, response);
return;
}
boolean supportCompression = false;
if (request instanceof HttpServletRequest) {
if (debug > 1) {
System.out.println("requestURI = " + ((HttpServletRequest)request).getRequestURI());
}
// Are we allowed to compress ?
String s = (String) ((HttpServletRequest)request).getParameter("gzip");
if ("false".equals(s)) {
if (debug > 0) {
System.out.println("got parameter gzip=false --> don't compress, just chain filter");
}
chain.doFilter(request, response);
return;
}
Enumeration e =
((HttpServletRequest)request).getHeaders("Accept-Encoding");
while (e.hasMoreElements()) {
String name = (String)e.n
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