001    /*
002     * Copyright 2003-2008 the original author or authors.
003     *
004     * Licensed under the Apache License, Version 2.0 (the "License");
005     * you may not use this file except in compliance with the License.
006     * You may obtain a copy of the License at
007     *
008     *     http://www.apache.org/licenses/LICENSE-2.0
009     *
010     * Unless required by applicable law or agreed to in writing, software
011     * distributed under the License is distributed on an "AS IS" BASIS,
012     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013     * See the License for the specific language governing permissions and
014     * limitations under the License.
015     *
016     * You are receiving this code free of charge, which represents many hours of
017     * effort from other individuals and corporations.  As a responsible member 
018     * of the community, you are asked (but not required) to donate any 
019     * enhancements or improvements back to the community under a similar open 
020     * source license.  Thank you. -TMN
021     */
022    package groovyx.net.http;
023    
024    import static groovyx.net.http.ContentEncoding.Type.GZIP;
025    
026    import java.io.IOException;
027    import java.io.InputStream;
028    import java.util.zip.GZIPInputStream;
029    
030    import org.apache.http.HttpEntity;
031    import org.apache.http.entity.HttpEntityWrapper;
032    
033    /**
034     * Content encoding used to handle GZIP responses.
035     * @author <a href='mailto:tnichols@enernoc.com'>Tom Nichols</a>
036     */
037    public class GZIPEncoding extends ContentEncoding {
038    
039            /**
040             * Returns the {@link Type#GZIP} encoding string which is added to the 
041             * <code>Accept</code> header by the base class.
042             */
043            @Override
044            public String getContentEncoding() {
045                    return GZIP.toString();
046            }
047            
048            /**
049             * Wraps the raw entity in a {@link GZIPDecompressingEntity}.
050             */
051            @Override
052            public HttpEntity wrapResponseEntity( HttpEntity raw ) {
053                    return new GZIPDecompressingEntity( raw );
054            }
055            
056            /**
057             * Entity used to interpret a GZIP-encoded response
058             * @author <a href='mailto:tnichols@enernoc.com'>Tom Nichols</a>
059             */
060        protected static class GZIPDecompressingEntity extends HttpEntityWrapper {
061    
062            public GZIPDecompressingEntity(final HttpEntity entity) {
063                super(entity);
064            }
065        
066            /**
067             * returns a {@link GZIPInputStream} which wraps the original entity's
068             * content stream
069             * @see HttpEntity#getContent()
070             */
071            @Override
072            public InputStream getContent() throws IOException, IllegalStateException {
073                return new GZIPInputStream( wrappedEntity.getContent() );
074            }
075    
076            /**
077             * @return -1
078             */
079            @Override
080            public long getContentLength() {
081                // length of un-gzipped content is not known
082                return -1;
083            }
084        }
085    }