001// Copyright 2009 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;
022
023import javax.servlet.http.HttpServletRequest;
024import javax.servlet.http.HttpServletResponse;
025import java.io.IOException;
026
027/**
028 * Filter that adds GZIP compression to the response, if the client supports it.
029 */
030public class GZipFilter implements HttpServletRequestFilter
031{
032    private final int cutover;
033
034    private final ResponseCompressionAnalyzer analyzer;
035
036    public GZipFilter(
037            @Symbol(SymbolConstants.MIN_GZIP_SIZE)
038            int cutover,
039
040            ResponseCompressionAnalyzer analyzer)
041    {
042        this.cutover = cutover;
043        this.analyzer = analyzer;
044    }
045
046    public boolean service(HttpServletRequest request, HttpServletResponse response, HttpServletRequestHandler handler)
047            throws IOException
048    {
049        HttpServletResponse newResponse = analyzer.isGZipSupported()
050                                          ? new GZIPEnabledResponse(response, request, cutover, analyzer)
051                                          : response;
052
053        return handler.service(request, newResponse);
054    }
055}