001// Copyright 2009, 2010, 2012 The Apache Software Foundation
002//
003// Licensed under the Apache License, Version 2.0 (the "License");
004// you may not use this file except in compliance with the License.
005// You may obtain a copy of the License at
006//
007// http://www.apache.org/licenses/LICENSE-2.0
008//
009// Unless required by applicable law or agreed to in writing, software
010// distributed under the License is distributed on an "AS IS" BASIS,
011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012// See the License for the specific language governing permissions and
013// limitations under the License.
014
015package org.apache.tapestry5.http.internal.gzip;
016
017import java.io.IOException;
018
019import javax.servlet.ServletOutputStream;
020import javax.servlet.http.HttpServletRequest;
021import javax.servlet.http.HttpServletResponse;
022import javax.servlet.http.HttpServletResponseWrapper;
023
024import org.apache.tapestry5.http.TapestryHttpConstants;
025import org.apache.tapestry5.http.services.CompressionAnalyzer;
026
027public class GZIPEnabledResponse extends HttpServletResponseWrapper
028{
029    private final int cutover;
030
031    private final HttpServletRequest request;
032
033    private final HttpServletResponse response;
034
035    private final CompressionAnalyzer analyzer;
036
037    private boolean contentLengthSet = false;
038
039    public GZIPEnabledResponse(HttpServletResponse response, HttpServletRequest request, int cutover,
040                               CompressionAnalyzer analyzer)
041    {
042        super(response);
043
044        this.request = request;
045        this.response = response;
046        this.cutover = cutover;
047        this.analyzer = analyzer;
048    }
049
050    public void setContentLength(int len)
051    {
052        super.setContentLength(len);
053
054        contentLengthSet = true;
055    }
056
057    @Override
058    public ServletOutputStream getOutputStream() throws IOException
059    {
060        if (contentLengthSet || isCompressionDisabled())
061            return super.getOutputStream();
062
063        String contentType = getContentType();
064
065        return new BufferedGZipOutputStream(contentType, response, cutover, analyzer);
066    }
067
068    private boolean isCompressionDisabled()
069    {
070        return request.getAttribute(TapestryHttpConstants.SUPPRESS_COMPRESSION) != null;
071    }
072}