    001    // Copyright 2011 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.assets;
    016
    017    import org.apache.tapestry5.internal.TapestryInternalUtils;
    018    import org.apache.tapestry5.ioc.Resource;
    019    import org.apache.tapestry5.services.assets.*;
    020
    021    import java.io.ByteArrayOutputStream;
    022    import java.io.IOException;
    023    import java.io.InputStream;
    024    import java.util.Map;
    025
    026    public class StreamableResourceSourceImpl implements StreamableResourceSource
    027    {
    028        private final Map<String, ResourceTransformer> configuration;
    029
    030        private final ContentTypeAnalyzer contentTypeAnalyzer;
    031
    032        private final CompressionAnalyzer compressionAnalyzer;
    033
    034        private final ResourceChangeTracker resourceChangeTracker;
    035
    036        public StreamableResourceSourceImpl(Map<String, ResourceTransformer> configuration,
    037                                            ContentTypeAnalyzer contentTypeAnalyzer, CompressionAnalyzer compressionAnalyzer,
    038                                            ResourceChangeTracker resourceChangeTracker)
    039        {
    040            this.configuration = configuration;
    041            this.contentTypeAnalyzer = contentTypeAnalyzer;
    042            this.compressionAnalyzer = compressionAnalyzer;
    043            this.resourceChangeTracker = resourceChangeTracker;
    044        }
    045
    046        public StreamableResource getStreamableResource(Resource baseResource, StreamableResourceProcessing processing, ResourceDependencies dependencies)
    047                throws IOException
    048        {
    049            assert baseResource != null;
    050
    051            if (!baseResource.exists())
    052            {
    053                throw new IOException(String.format("Resource %s does not exist.", baseResource));
    054            }
    055
    056            String fileSuffix = TapestryInternalUtils.toFileSuffix(baseResource.getFile());
    057
    058            // Optionally, transform the resource. The main driver for this is to allow
    059            // for libraries like LessJS (http://lesscss.org/) or
    060            // http://jashkenas.github.com/coffee-script/
    061            ResourceTransformer rt = configuration.get(fileSuffix);
    062
    063            InputStream transformed = rt == null ? baseResource.openStream() : rt.transform(baseResource, dependencies);
    064
    065            assert transformed != null;
    066
    067            BytestreamCache bytestreamCache = readStream(transformed);
    068
    069            transformed.close();
    070
    071            String contentType = contentTypeAnalyzer.getContentType(baseResource);
    072
    073            boolean compressable = compressionAnalyzer.isCompressable(contentType);
    074
    075            long lastModified = resourceChangeTracker.trackResource(baseResource);
    076
    077            return new StreamableResourceImpl(baseResource.toString(), contentType, compressable ? CompressionStatus.COMPRESSABLE
    078                    : CompressionStatus.NOT_COMPRESSABLE, lastModified, bytestreamCache);
    079        }
    080
    081        private BytestreamCache readStream(InputStream stream) throws IOException
    082        {
    083            ByteArrayOutputStream bos = new ByteArrayOutputStream();
    084
    085            TapestryInternalUtils.copy(stream, bos);
    086
    087            stream.close();
    088
    089            return new BytestreamCache(bos);
    090        }
    091
    092    }