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
015package org.apache.tapestry5.internal.services.assets;
016
017import org.apache.tapestry5.internal.TapestryInternalUtils;
018import org.apache.tapestry5.ioc.Resource;
019import org.apache.tapestry5.services.assets.*;
020
021import java.io.ByteArrayOutputStream;
022import java.io.IOException;
023import java.io.InputStream;
024import java.util.Map;
025
026public 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}