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    
015    package org.apache.tapestry5.internal.services;
016    
017    import org.apache.tapestry5.SymbolConstants;
018    import org.apache.tapestry5.internal.TapestryInternalUtils;
019    import org.apache.tapestry5.ioc.annotations.Symbol;
020    import org.apache.tapestry5.services.ResponseCompressionAnalyzer;
021    import org.apache.tapestry5.services.assets.CompressionAnalyzer;
022    
023    import javax.servlet.http.HttpServletRequest;
024    import java.util.Collection;
025    
026    public class ResponseCompressionAnalyzerImpl implements ResponseCompressionAnalyzer
027    {
028        private final HttpServletRequest request;
029    
030        private final boolean gzipCompressionEnabled;
031    
032        private final CompressionAnalyzer analyzer;
033    
034        // configuration is left here for partial compatibility with end-user modules that contribute a value; they
035        // should contribute to CompressionAnalyzer instead.
036        public ResponseCompressionAnalyzerImpl(HttpServletRequest request, CompressionAnalyzer analyzer, @Deprecated
037        Collection<String> configuration, @Symbol(SymbolConstants.GZIP_COMPRESSION_ENABLED)
038        boolean gzipCompressionEnabled)
039        {
040            this.request = request;
041            this.analyzer = analyzer;
042            this.gzipCompressionEnabled = gzipCompressionEnabled;
043        }
044    
045        public boolean isGZipSupported()
046        {
047            if (!gzipCompressionEnabled)
048            {
049                return false;
050            }
051    
052            // TAP5-1880:
053            if (request.getProtocol() == "HTTP/1.0")
054            {
055                return false;
056            }
057    
058            String supportedEncodings = request.getHeader("Accept-Encoding");
059    
060            if (supportedEncodings == null)
061            {
062                return false;
063            }
064    
065            for (String encoding : TapestryInternalUtils.splitAtCommas(supportedEncodings))
066            {
067                if (encoding.equalsIgnoreCase("gzip"))
068                {
069                    return true;
070                }
071            }
072    
073            return false;
074        }
075    
076        public boolean isCompressable(String contentType)
077        {
078            return analyzer.isCompressable(contentType);
079        }
080    }