    001// Licensed under the Apache License, Version 2.0 (the "License");
    002// you may not use this file except in compliance with the License.
    003// You may obtain a copy of the License at
    004//
    005// http://www.apache.org/licenses/LICENSE-2.0
    006//
    007// Unless required by applicable law or agreed to in writing, software
    008// distributed under the License is distributed on an "AS IS" BASIS,
    009// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    010// See the License for the specific language governing permissions and
    011// limitations under the License.
    012
    013package org.apache.tapestry5.internal.services.assets;
    014
    015import org.apache.tapestry5.commons.Resource;
    016import org.apache.tapestry5.commons.util.CollectionFactory;
    017import org.apache.tapestry5.http.ContentType;
    018import org.apache.tapestry5.http.services.CompressionAnalyzer;
    019import org.apache.tapestry5.internal.TapestryInternalUtils;
    020import org.apache.tapestry5.services.assets.*;
    021
    022import java.io.ByteArrayOutputStream;
    023import java.io.IOException;
    024import java.io.InputStream;
    025import java.util.Map;
    026import java.util.Set;
    027
    028public class StreamableResourceSourceImpl implements StreamableResourceSource
    029{
    030    private final Map<String, ResourceTransformer> configuration;
    031
    032    private final ContentTypeAnalyzer contentTypeAnalyzer;
    033
    034    private final CompressionAnalyzer compressionAnalyzer;
    035
    036    private final ResourceChangeTracker resourceChangeTracker;
    037
    038    private final AssetChecksumGenerator checksumGenerator;
    039
    040    public StreamableResourceSourceImpl(Map<String, ResourceTransformer> configuration,
    041                                        ContentTypeAnalyzer contentTypeAnalyzer, CompressionAnalyzer compressionAnalyzer,
    042                                        ResourceChangeTracker resourceChangeTracker, AssetChecksumGenerator checksumGenerator)
    043    {
    044        this.configuration = configuration;
    045        this.contentTypeAnalyzer = contentTypeAnalyzer;
    046        this.compressionAnalyzer = compressionAnalyzer;
    047        this.resourceChangeTracker = resourceChangeTracker;
    048        this.checksumGenerator = checksumGenerator;
    049    }
    050
    051    public Set<String> fileExtensionsForContentType(ContentType contentType)
    052    {
    053        Set<String> result = CollectionFactory.newSet();
    054
    055        for (Map.Entry<String, ResourceTransformer> me : configuration.entrySet())
    056        {
    057            if (me.getValue().getTransformedContentType().equals(contentType))
    058            {
    059                result.add(me.getKey());
    060            }
    061        }
    062
    063        return result;
    064    }
    065
    066    public StreamableResource getStreamableResource(Resource baseResource, StreamableResourceProcessing processing, ResourceDependencies dependencies)
    067            throws IOException
    068    {
    069        assert baseResource != null;
    070
    071        if (!baseResource.exists())
    072        {
    073            throw new IOException(String.format("Resource %s does not exist.", baseResource));
    074        }
    075
    076        String fileSuffix = TapestryInternalUtils.toFileSuffix(baseResource.getFile());
    077
    078        // Optionally, transform the resource. The main driver for this is to allow
    079        // for libraries like LessJS (http://lesscss.org/) or
    080        // http://jashkenas.github.com/coffee-script/
    081        ResourceTransformer rt = configuration.get(fileSuffix);
    082
    083        InputStream transformed = rt == null ? baseResource.openStream() : rt.transform(baseResource, dependencies);
    084
    085        assert transformed != null;
    086
    087        BytestreamCache bytestreamCache = readStream(transformed);
    088
    089        transformed.close();
    090
    091        ContentType contentType = rt == null
    092                ? new ContentType(contentTypeAnalyzer.getContentType(baseResource))
    093                : rt.getTransformedContentType();
    094
    095        boolean compressable = compressionAnalyzer.isCompressable(contentType.getMimeType());
    096
    097        long lastModified = resourceChangeTracker.trackResource(baseResource);
    098
    099        return new StreamableResourceImpl(baseResource.toString(), contentType, compressable ? CompressionStatus.COMPRESSABLE
    100                : CompressionStatus.NOT_COMPRESSABLE, lastModified, bytestreamCache, checksumGenerator, null);
    101    }
    102
    103    private BytestreamCache readStream(InputStream stream) throws IOException
    104    {
    105        ByteArrayOutputStream bos = new ByteArrayOutputStream();
    106
    107        TapestryInternalUtils.copy(stream, bos);
    108
    109        stream.close();
    110
    111        return new BytestreamCache(bos);
    112    }
    113
    114}