001/*
002 * (C) Copyright 2006-2016 Nuxeo SA (http://nuxeo.com/) and others.
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 */
017package org.nuxeo.ecm.platform.preview.adapter.base;
018
019import java.io.File;
020import java.io.IOException;
021import java.io.InputStream;
022import java.util.List;
023
024import org.apache.commons.codec.digest.DigestUtils;
025import org.apache.commons.logging.Log;
026import org.apache.commons.logging.LogFactory;
027
028import org.nuxeo.ecm.core.api.Blob;
029import org.nuxeo.ecm.core.api.blobholder.BlobHolder;
030import org.nuxeo.ecm.core.api.blobholder.DocumentBlobHolder;
031import org.nuxeo.ecm.core.convert.api.ConversionException;
032import org.nuxeo.ecm.core.convert.api.ConversionService;
033import org.nuxeo.ecm.platform.mimetype.MimetypeDetectionException;
034import org.nuxeo.ecm.platform.mimetype.MimetypeNotFoundException;
035import org.nuxeo.ecm.platform.mimetype.interfaces.MimetypeRegistry;
036import org.nuxeo.ecm.platform.preview.adapter.MimeTypePreviewer;
037import org.nuxeo.ecm.platform.preview.adapter.PreviewAdapterManager;
038import org.nuxeo.ecm.platform.preview.api.NothingToPreviewException;
039import org.nuxeo.ecm.platform.preview.api.PreviewException;
040import org.nuxeo.runtime.api.Framework;
041import org.nuxeo.runtime.services.config.ConfigurationService;
042
043/**
044 * Base class for preview based on "on the fly" HTML transformers
045 *
046 * @author tiry
047 */
048public class ConverterBasedHtmlPreviewAdapter extends AbstractHtmlPreviewAdapter {
049
050    private static final Log log = LogFactory.getLog(ConverterBasedHtmlPreviewAdapter.class);
051
052    protected String defaultFieldXPath;
053
054    protected MimetypeRegistry mimeTypeService;
055
056    /**
057     * @since 8.10
058     */
059    protected static final String ALLOW_ZIP_PREVIEW = "nuxeo.preview.zip.enabled";
060
061    public ConversionService getConversionService() {
062        return Framework.getService(ConversionService.class);
063    }
064
065    @Override
066    protected PreviewAdapterManager getPreviewManager() {
067        return Framework.getService(PreviewAdapterManager.class);
068    }
069
070    protected static String getMimeType(Blob blob) {
071        if (blob == null) {
072            return null;
073        }
074
075        String srcMT = blob.getMimeType();
076        if (srcMT == null || srcMT.startsWith("application/octet-stream")) {
077            // call MT Service
078            try {
079                MimetypeRegistry mtr = Framework.getService(MimetypeRegistry.class);
080                srcMT = mtr.getMimetypeFromFilenameAndBlobWithDefault(blob.getFilename(), blob,
081                        "application/octet-stream");
082                log.debug("mime type service returned " + srcMT);
083            } catch (MimetypeDetectionException e) {
084                log.warn("error while calling Mimetype service", e);
085            }
086        }
087        return srcMT;
088    }
089
090    protected String getMimeType(String xpath) {
091        BlobHolder blobHolder2preview = getBlobHolder2preview(xpath);
092        Blob blob = getBlob2preview(blobHolder2preview);
093        return getMimeType(blob);
094    }
095
096    protected String getDefaultPreviewFieldXPath() {
097        return defaultFieldXPath;
098    }
099
100    public void setDefaultPreviewFieldXPath(String xPath) {
101        defaultFieldXPath = xPath;
102    }
103
104    @Override
105    public List<Blob> getPreviewBlobs() throws PreviewException {
106        return getPreviewBlobs(getDefaultPreviewFieldXPath());
107    }
108
109    @Override
110    public boolean hasPreview(String xpath) {
111        String srcMT = getMimeType(xpath);
112        if ("application/zip".equals(srcMT)
113                && !Framework.getService(ConfigurationService.class).isBooleanPropertyTrue(ALLOW_ZIP_PREVIEW)) {
114            return false;
115        }
116        MimeTypePreviewer mtPreviewer = getPreviewManager().getPreviewer(srcMT);
117        return mtPreviewer != null || getConversionService().getConverterName(srcMT, "text/html") != null;
118    }
119
120    @Override
121    public List<Blob> getPreviewBlobs(String xpath) throws PreviewException {
122        BlobHolder blobHolder2preview = getBlobHolder2preview(xpath);
123        Blob blob2Preview = getBlob2preview(blobHolder2preview);
124
125        String srcMT = getMimeType(xpath);
126        log.debug("Source type for HTML preview =" + srcMT);
127        MimeTypePreviewer mtPreviewer = getPreviewManager().getPreviewer(srcMT);
128        if (mtPreviewer != null) {
129            return mtPreviewer.getPreview(blob2Preview, adaptedDoc);
130        }
131
132        String converterName = getConversionService().getConverterName(srcMT, "text/html");
133        if (converterName == null) {
134            log.debug("No dedicated converter found, using generic");
135            converterName = "any2html";
136        }
137
138        BlobHolder result;
139        try {
140            result = getConversionService().convert(converterName, blobHolder2preview, null);
141            setMimeType(result);
142            setDigest(result);
143            return result.getBlobs();
144        } catch (ConversionException e) {
145            throw new PreviewException(e.getMessage(), e);
146        }
147    }
148
149    /**
150     * @since 5.7.3
151     */
152    private Blob getBlob2preview(BlobHolder blobHolder2preview) throws PreviewException {
153        Blob blob2Preview = blobHolder2preview.getBlob();
154        if (blob2Preview == null) {
155            throw new NothingToPreviewException("Can not preview a document without blob");
156        } else {
157            return blob2Preview;
158        }
159    }
160
161    /**
162     * Returns a blob holder suitable for a preview.
163     *
164     * @since 5.7.3
165     */
166    private BlobHolder getBlobHolder2preview(String xpath) {
167        if ((xpath == null) || ("default".equals(xpath))) {
168            return adaptedDoc.getAdapter(BlobHolder.class);
169        } else {
170            return new DocumentBlobHolder(adaptedDoc, xpath);
171        }
172    }
173
174    protected void setMimeType(BlobHolder result) {
175        for (Blob blob : result.getBlobs()) {
176            if ((blob.getMimeType() == null || blob.getMimeType().startsWith("application/octet-stream"))
177                    && blob.getFilename().endsWith("html")) {
178                String mimeTpye = getMimeType(blob);
179                blob.setMimeType(mimeTpye);
180            }
181        }
182    }
183
184    protected void setDigest(BlobHolder result) {
185        for (Blob blob : result.getBlobs()) {
186            if (blob.getDigest() == null) {
187                try (InputStream stream = blob.getStream()) {
188                    String digest = DigestUtils.md5Hex(stream);
189                    blob.setDigest(digest);
190                } catch (IOException e) {
191                    log.warn("Unable to compute digest of blob.", e);
192                }
193            }
194        }
195    }
196
197    public String getMimeType(File file) throws ConversionException {
198        try {
199            return getMimeTypeService().getMimetypeFromFile(file);
200        } catch (ConversionException e) {
201            throw new ConversionException("Could not get MimeTypeRegistry");
202        } catch (MimetypeNotFoundException e) {
203            return "application/octet-stream";
204        } catch (MimetypeDetectionException e) {
205            return "application/octet-stream";
206        }
207    }
208
209    public MimetypeRegistry getMimeTypeService() throws ConversionException {
210        if (mimeTypeService == null) {
211            mimeTypeService = Framework.getService(MimetypeRegistry.class);
212        }
213        return mimeTypeService;
214    }
215
216    @Override
217    public void cleanup() {
218
219    }
220
221    @Override
222    public boolean cachable() {
223        return true;
224    }
225
226    @Override
227    public boolean hasBlobToPreview() throws PreviewException {
228        String xpath = getDefaultPreviewFieldXPath();
229        Blob blob2Preview;
230        try {
231            blob2Preview = getBlob2preview(getBlobHolder2preview(xpath));
232        } catch (NothingToPreviewException e) {
233            return false;
234        }
235        String srcMT = getMimeType(xpath);
236        if ("application/zip".equals(srcMT)
237                && !Framework.getService(ConfigurationService.class).isBooleanPropertyTrue(ALLOW_ZIP_PREVIEW)) {
238            return false;
239        }
240        return blob2Preview != null;
241    }
242
243}