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    
015    package org.apache.tapestry5.internal.gzip;
016    
017    import org.apache.tapestry5.SymbolConstants;
018    import org.apache.tapestry5.ioc.annotations.Symbol;
019    import org.apache.tapestry5.services.HttpServletRequestFilter;
020    import org.apache.tapestry5.services.HttpServletRequestHandler;
021    import org.apache.tapestry5.services.ResponseCompressionAnalyzer;
022    
023    import javax.servlet.http.HttpServletRequest;
024    import javax.servlet.http.HttpServletResponse;
025    import java.io.IOException;
026    
027    /**
028     * Filter that adds GZIP compression to the response, if the client supports it.
029     */
030    public 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    }