/*==========================================================================*\
| $Id: SmartGZIPOutputStream.java,v 1.1 2011/05/13 19:46:57 aallowat Exp $
|*-------------------------------------------------------------------------*|
| Copyright (C) 2011 Virginia Tech
|
| This file is part of Web-CAT.
|
| Web-CAT is free software; you can redistribute it and/or modify
| it under the terms of the GNU Affero General Public License as published
| by the Free Software Foundation; either version 3 of the License, or
| (at your option) any later version.
|
| Web-CAT is distributed in the hope that it will be useful,
| but WITHOUT ANY WARRANTY; without even the implied warranty of
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
| GNU General Public License for more details.
|
| You should have received a copy of the GNU Affero General Public License
| along with Web-CAT; if not, see <http://www.gnu.org/licenses/>.
\*==========================================================================*/
package org.webcat.core.http;
import java.io.IOException;
import java.io.OutputStream;
import java.util.zip.GZIPOutputStream;
import org.eclipse.jgit.util.HttpSupport;
import org.eclipse.jgit.util.TemporaryBuffer;
import org.webcat.core.NSMutableDataOutputStream;
import com.webobjects.appserver.WORequest;
import com.webobjects.appserver.WOResponse;
//-------------------------------------------------------------------------
/**
* An output stream that automatically GZIPs its content before appending it
* to a response if the request supports GZIP encoding.
*
* @author Tony Allevato
* @author Last changed by $Author: aallowat $
* @version $Revision: 1.1 $, $Date: 2011/05/13 19:46:57 $
*/
public class SmartGZIPOutputStream extends TemporaryBuffer
{
//~ Constructors ..........................................................
// ----------------------------------------------------------
/**
* Creates a new {@code SmartGZIPOutputStream} for the specified request
* and response.
*
* @param request the request
* @param response the response
*/
public SmartGZIPOutputStream(WORequest request, WOResponse response)
{
super(LIMIT);
this.request = request;
this.response = response;
this.outputStream = new NSMutableDataOutputStream();
}
//~ Methods ...............................................................
// ----------------------------------------------------------
@Override
protected OutputStream overflow() throws IOException
{
startedOutput = true;
return outputStream;
}
// ----------------------------------------------------------
@Override
public void close() throws IOException
{
super.close();
if (!startedOutput)
{
TemporaryBuffer out = this;
if (out.length() > 256 && RequestUtils.acceptsGZIPEncoding(request))
{
TemporaryBuffer gzbuf = new TemporaryBuffer.Heap(LIMIT);
try
{
GZIPOutputStream gzip = new GZIPOutputStream(gzbuf);
out.writeTo(gzip, null);
gzip.close();
if (gzbuf.length() < out.length())
{
out = gzbuf;
response.setHeader(HttpSupport.ENCODING_GZIP,
HttpSupport.HDR_CONTENT_ENCODING);
}
}
catch (IOException e)
{
// Likely caused by overflowing the buffer, meaning the
// data would be larger if compressed. Discard compressed
// copy and use the original.
}
}
out.writeTo(outputStream, null);
outputStream.flush();
}
// Finally, append whatever was dumped into our stream to the response
// content.
outputStream.close();
response.appendContentData(outputStream.data());
}
//~ Static/instance variables .............................................
private static final int LIMIT = 32 * 1024;
private WORequest request;
private WOResponse response;
private NSMutableDataOutputStream outputStream;
private boolean startedOutput;
}