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.http.internal.gzip;
016
017import java.io.IOException;
018
019import javax.servlet.http.HttpServletRequest;
020import javax.servlet.http.HttpServletResponse;
021
022import org.apache.tapestry5.http.TapestryHttpSymbolConstants;
023import org.apache.tapestry5.http.services.CompressionAnalyzer;
024import org.apache.tapestry5.http.services.HttpServletRequestFilter;
025import org.apache.tapestry5.http.services.HttpServletRequestHandler;
026import org.apache.tapestry5.http.services.ResponseCompressionAnalyzer;
027import org.apache.tapestry5.ioc.annotations.Symbol;
028
029/**
030 * Filter that adds GZIP compression to the response, if the client supports it.
031 */
032public class GZipFilter implements HttpServletRequestFilter
033{
034    private final int cutover;
035
036    private final ResponseCompressionAnalyzer responseAnalyzer;
037
038    private final CompressionAnalyzer compressionAnalyzer;
039
040    public GZipFilter(
041            @Symbol(TapestryHttpSymbolConstants.MIN_GZIP_SIZE)
042            int cutover,
043
044            ResponseCompressionAnalyzer responseAnalyzer,
045
046            CompressionAnalyzer compressionAnalyzer)
047    {
048        this.cutover = cutover;
049        this.responseAnalyzer = responseAnalyzer;
050        this.compressionAnalyzer = compressionAnalyzer;
051    }
052
053    public boolean service(HttpServletRequest request, HttpServletResponse response, HttpServletRequestHandler handler)
054            throws IOException
055    {
056        HttpServletResponse newResponse = responseAnalyzer.isGZipSupported()
057                ? new GZIPEnabledResponse(response, request, cutover, compressionAnalyzer)
058                : response;
059
060        return handler.service(request, newResponse);
061    }
062}