AudioTextExtractor.java

/**
 *  OpenKM, Open Document Management System (http://www.openkm.com)
 *  Copyright (c) 2006-2011  Paco Avila & Josep Llort
 *
 *  No bytes were intentionally harmed during the development of this application.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *  
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

package com.openkm.extractor;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import java.io.StringReader;
import java.util.Iterator;

import org.apache.commons.io.IOUtils;
import org.apache.jackrabbit.extractor.AbstractTextExtractor;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import entagged.audioformats.AudioFile;
import entagged.audioformats.AudioFileIO;
import entagged.audioformats.Tag;
import entagged.audioformats.exceptions.CannotReadException;
import entagged.audioformats.mp3.util.id3frames.TextId3Frame;
import entagged.audioformats.ogg.util.OggTagField;

/**
 * Text extractor for audio documents.
 * Use java metadata extraction library from 
 * http://entagged.sourceforge.net/
 */
public class AudioTextExtractor extends AbstractTextExtractor {

    /**
     * Logger instance.
     */
    private static final Logger log = LoggerFactory.getLogger(AudioTextExtractor.class);

    /**
     * Creates a new <code>AudioTextExtractor</code> instance.
     */
    public AudioTextExtractor() {
        super(new String[]{"audio/mpeg", "audio/x-ogg"});
    }
    
    //-------------------------------------------------------< TextExtractor >

    /**
     * {@inheritDoc}
     */ 
	@SuppressWarnings("unchecked")
	public Reader extractText(InputStream stream, String type, String encoding) throws IOException {
    	File tmpFile = null;
    	
    	try {
    		if (type.equals("audio/mpeg")) {
    			tmpFile = File.createTempFile("okm", ".mp3");
    		} else if (type.equals("audio/x-ogg")) {
    			tmpFile = File.createTempFile("okm", ".ogg");
    		}
    		
    		FileOutputStream fos = new FileOutputStream(tmpFile);
    		IOUtils.copy(stream, fos);
    		fos.close();

    		StringBuffer sb = new StringBuffer();
    		AudioFile af = AudioFileIO.read(tmpFile);
    		Tag tag = af.getTag();
    		    		
    		for (Iterator<Object> it = tag.getFields(); it.hasNext() ;) { 
    			Object o = it.next();
    			
    			if (o instanceof TextId3Frame) {
    				TextId3Frame tf = (TextId3Frame) o;
    				sb.append("[ID3] ");
    				sb.append(tf.getId());
    				sb.append("=");
    				sb.append(tf.getContent());
    				sb.append("\n");
    			} else if (o instanceof OggTagField) {
    				OggTagField tf = (OggTagField) o;
    				sb.append("[OGG] ");
    				sb.append(tf.getId());
    				sb.append("=");
    				sb.append(tf.getContent());
    				sb.append("\n");
    			}
    		}
    		
    		log.debug("TEXT: "+sb.toString());
            return new StringReader(sb.toString());
		} catch (CannotReadException e) {
            log.warn("Failed to extract tag information", e);
            return new StringReader("");
		} finally {
			stream.close();
			tmpFile.delete();
        }
    }
}