SanslanContentDigester.java

/**********************************************************************************
 * $URL: https://source.sakaiproject.org/svn/search/trunk/search-impl/impl/src/java/org/sakaiproject/search/component/adapter/contenthosting/SanslanContentDigester.java $
 * $Id: SanslanContentDigester.java 105078 2012-02-24 23:00:38Z ottenhoff@longsight.com $
 ***********************************************************************************
 *
 * Copyright (c) 2003, 2004, 2005, 2006, 2007, 2008, 2009 The Sakai Foundation
 *
 * Licensed under the Educational Community License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *       http://www.opensource.org/licenses/ECL-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 **********************************************************************************/
package org.sakaiproject.search.component.adapter.contenthosting;


import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import java.io.StringReader;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.sanselan.ImageReadException;
import org.apache.sanselan.Sanselan;
import org.apache.sanselan.common.IImageMetadata;
import org.apache.sanselan.formats.jpeg.JpegImageMetadata;
import org.apache.sanselan.formats.tiff.TiffField;
import org.apache.sanselan.formats.tiff.TiffImageMetadata;
import org.apache.sanselan.formats.tiff.constants.TagInfo;
import org.apache.sanselan.formats.tiff.constants.TiffConstants;
import org.sakaiproject.content.api.ContentResource;
import org.sakaiproject.entity.api.ResourceProperties;
import org.sakaiproject.exception.ServerOverloadException;

public class SanslanContentDigester extends BaseContentDigester {
	private static Log log = LogFactory.getLog(TikaContentDigester.class);
	
	public String getContent(ContentResource contentResource) {
		log.debug("digesting: " + contentResource.getId());
		
		InputStream contentStream = null;
		IImageMetadata metadata = null;

		try {
			contentStream = contentResource.streamContent();
			ResourceProperties resourceProperties = contentResource.getProperties();
			String fileName = resourceProperties.getProperty(resourceProperties.getNamePropDisplayName());
			try {
				metadata = Sanselan.getMetadata(contentStream, fileName);
				StringBuffer sb = new StringBuffer();
				if (metadata instanceof JpegImageMetadata) {
					JpegImageMetadata jpegMetadata = (JpegImageMetadata) metadata;
					sb.append(getFieldValue(jpegMetadata, TiffConstants.EXIF_TAG_MAKE));
					sb.append(getFieldValue(jpegMetadata, TiffConstants.EXIF_TAG_MODEL));
					sb.append(getFieldValue(jpegMetadata, TiffConstants.EXIF_TAG_ARTIST));
					sb.append(getFieldValue(jpegMetadata, TiffConstants.EXIF_TAG_USER_COMMENT));
					//get the GPS info 
					//TODO this should go in its own field in the index
					TiffImageMetadata exifMetadata = jpegMetadata.getExif();
					if (exifMetadata != null) {
						try {
							TiffImageMetadata.GPSInfo gpsInfo = exifMetadata.getGPS();
							if (null != gpsInfo) {
								double longitude = gpsInfo.getLongitudeAsDegreesEast();
								double latitude = gpsInfo.getLatitudeAsDegreesNorth();
								sb.append("GPS Description: " + gpsInfo + "\n");
								sb.append("GPS Longitude: " + longitude + "\n");
								sb.append("GPS Latitude: " + latitude + "\n");
							}
						} catch (ImageReadException e) {
							e.printStackTrace();
						}

					}	
				}
				log.debug("got metadata: " + sb.toString());
				return sb.toString();
			} catch (ImageReadException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		} catch (ServerOverloadException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
		
		return null;
	}

	private String getFieldValue(JpegImageMetadata metadata,
			TagInfo tagInfo) {
			TiffField field = metadata.findEXIFValue(tagInfo);
            if (field == null) {
               return "";
            } else {
                return(tagInfo.name + ": " +
                    field.getValueDescription() + "\n");
            }

	}

	public Reader getContentReader(ContentResource contentResource) {
		
		return new StringReader(this.getContent(contentResource));
	}

}