001// Copyright 2009, 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.internal.gzip;
016
017import org.apache.tapestry5.SymbolConstants;
018import org.apache.tapestry5.ioc.annotations.Symbol;
019import org.apache.tapestry5.services.HttpServletRequestFilter;
020import org.apache.tapestry5.services.HttpServletRequestHandler;
021import org.apache.tapestry5.services.ResponseCompressionAnalyzer;
022import org.apache.tapestry5.services.assets.CompressionAnalyzer;
023
024import javax.servlet.http.HttpServletRequest;
025import javax.servlet.http.HttpServletResponse;
026import java.io.IOException;
027
028/**
029 * Filter that adds GZIP compression to the response, if the client supports it.
030 */
031public class GZipFilter implements HttpServletRequestFilter
032{
033    private final int cutover;
034
035    private final ResponseCompressionAnalyzer responseAnalyzer;
036
037    private final CompressionAnalyzer compressionAnalyzer;
038
039    public GZipFilter(
040            @Symbol(SymbolConstants.MIN_GZIP_SIZE)
041            int cutover,
042
043            ResponseCompressionAnalyzer responseAnalyzer,
044
045            CompressionAnalyzer compressionAnalyzer)
046    {
047        this.cutover = cutover;
048        this.responseAnalyzer = responseAnalyzer;
049        this.compressionAnalyzer = compressionAnalyzer;
050    }
051
052    public boolean service(HttpServletRequest request, HttpServletResponse response, HttpServletRequestHandler handler)
053            throws IOException
054    {
055        HttpServletResponse newResponse = responseAnalyzer.isGZipSupported()
056                ? new GZIPEnabledResponse(response, request, cutover, compressionAnalyzer)
057                : response;
058
059        return handler.service(request, newResponse);
060    }
061}