/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache 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.apache.org/licenses/LICENSE-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.apache.pdfbox.lucene;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;
import java.io.StringWriter;
import java.util.Calendar;
import java.net.URL;
import java.net.URLConnection;
import java.util.Date;
import org.apache.lucene.document.DateTools;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDDocumentInformation;
import org.apache.pdfbox.exceptions.CryptographyException;
import org.apache.pdfbox.exceptions.InvalidPasswordException;
import org.apache.pdfbox.util.PDFTextStripper;
/**
* This class is used to create a document for the lucene search engine.
* This should easily plug into the IndexHTML or IndexFiles that comes with
* the lucene project. This class will populate the following fields.
* <table>
* <tr>
* <th>Lucene Field Name</th>
* <th>Description</th>
* </tr>
* <tr>
* <td>path</td>
* <td>File system path if loaded from a file</td>
* </tr>
* <tr>
* <td>url</td>
* <td>URL to PDF document</td>
* </tr>
* <tr>
* <td>contents</td>
* <td>Entire contents of PDF document, indexed but not stored</td>
* </tr>
* <tr>
* <td>summary</td>
* <td>First 500 characters of content</td>
* </tr>
* <tr>
* <td>modified</td>
* <td>The modified date/time according to the url or path</td>
* </tr>
* <tr>
* <td>uid</td>
* <td>A unique identifier for the Lucene document.</td>
* </tr>
* <tr>
* <td>CreationDate</td>
* <td>From PDF meta-data if available</td>
* </tr>
* <tr>
* <td>Creator</td>
* <td>From PDF meta-data if available</td>
* </tr>
* <tr>
* <td>Keywords</td>
* <td>From PDF meta-data if available</td>
* </tr>
* <tr>
* <td>ModificationDate</td>
* <td>From PDF meta-data if available</td>
* </tr>
* <tr>
* <td>Producer</td>
* <td>From PDF meta-data if available</td>
* </tr>
* <tr>
* <td>Subject</td>
* <td>From PDF meta-data if available</td>
* </tr>
* <tr>
* <td>Trapped</td>
* <td>From PDF meta-data if available</td>
* </tr>
* </table>
*
* @author <a href="mailto:ben@benlitchfield.com">Ben Litchfield</a>
* @version $Revision: 1.23 $
*/
public class LucenePDFDocument
{
private static final char FILE_SEPARATOR = System.getProperty("file.separator").charAt(0);
// given caveat of increased search times when using
//MICROSECOND, only use SECOND by default
private DateTools.Resolution dateTimeResolution = DateTools.Resolution.SECOND;
private PDFTextStripper stripper = null;
/**
* Constructor.
*/
public LucenePDFDocument()
{
}
/**
* Set the text stripper that will be used during extraction.
*
* @param aStripper The new pdf text stripper.
*/
public void setTextStripper( PDFTextStripper aStripper )
{
stripper = aStripper;
}
/**
* Get the Lucene data time resolution.
*
* @return current date/time resolution
*/
public DateTools.Resolution getDateTimeResolution()
{
return dateTimeResolution;
}
/**
* Set the Lucene data time resolution.
*
* @param resolution set new date/time resolution
*/
public void setDateTimeResolution( DateTools.Resolution resolution )
{
dateTimeResolution = resolution;
}
//
// compatibility methods for lucene-1.9+
//
private String timeToString( long time )
{
return DateTools.timeToString( time, dateTimeResolution );
}
private void addKeywordField( Document document, String name, String value )
{
if ( value != null )
{
document.add( new Field( name, value, Field.Store.YES, Field.Index.NOT_ANALYZED ) );
}
}
private void addTextField( Document document, String name, Reader value )
{
if ( value != null )
{
document.add( new Field( name, value ) );
}
}
private void addTextField( Document document, String name, String value )
{
if ( value != null )
{
document.add( new Field( name, value, Field.Store.YES, Field.Index.ANALYZED ) );
}
}
private void addTextField( Document document, String name, Date value )
{
if ( value != null )
{
addTextField( document, name, DateTools.dateToString( value, dateTimeResolution ) );
}
}
private void addTextField( Document document, String name, Calendar value )
{
if ( value != null )
{
addTextField( document, name, value.getTime() );
}
}
private static void addUnindexedField( Document document, String name, String value )
{
if ( value != null )
{
document.add( new Field( name, value, Field.Store.YES, Field.Index.NO ) );
}
}
private void addUnstoredKeywordField( Document document, String name, String value )
{
if ( value != null )
{
document.add( new Field( name, value, Field.Store.NO, Field.Index.NOT_ANALYZED ) );
}
}
/**
* Convert the PDF stream to a lucene document.
*
* @param is The input stream.
* @return The input stream converted to a lucene document.
* @throws IOException If there is an error converting the PDF.
*/
public Document convertDocument( InputStream is ) throws IOException
{
Document document = new Document();
addContent( document, is, "<inputstream>" );
return document;
}
/**
* This will take a reference to a PDF document and create a lucene document.
*
* @param file A reference to a PDF document.
* @return The converted lucene document.
*
* @throws IOException If there is an exception while converting the document.
*/
public Document convertDocument( File file ) throws IOException
{
Document document = new Document();
// Add the url as a field named "url". Use an UnIndexed field, so
// that the url is just stored with the document, but is not searchable.
addUnindexedField( document, "path", file.getPath() );
addUnindexedField( document, "url", file.getPath().replace(FILE_SEPARATOR, '/') );
// Add the last modified date of the file a field named "modified". Use a
// Keyword field, so that it's searchable, but so that no attempt is made
// to tokenize the field into words.
addKeywordField( document, "modified", timeToString( file.lastModified() ) );
String uid = file.getPath().replace(FILE_SEPARATOR,'\u0000')
+ "\u0000"
+ timeToString( file.lastModified() );
// Add the uid as a field, so that index can be incrementally maintained.
// This field is not stored with document, it is indexed, but it is not
// tokenized prior to indexing.
addUnstoredKeywordField( document, "uid", uid );
FileInputStream input = null;
try
{
input = new FileInputStream( file );
addContent( document, input, file.getPath() );
}
finally
{
if( input != null )
{
input.close();
}
}
// return the document
return document;
}
/**
* Convert the document from a PDF to a lucene document.
*
* @param url A url to a PDF document.
* @return The PDF converted to a lucene document.
* @throws IOException If there is an error while converting the document.
*/
public Document convertDocument( URL url ) throws IOException
{
Document document = new Document();
URLConnection connection = url.openConnection();
connection.connect();
// Add the url as a field named "url". Use an UnIndexed field, so
// that the url is just stored with the document, but is not searchable.
addUnindexedField( document, "url", url.toExternalForm() );
// Add the last modified date of the file a field named "modified". Use a
// Keyword field, so that it's searchable, but so that no attempt is made
// to tokenize the field into words.
addKeywordField( document, "modified", timeToString(connection.getLastModified() ) );
String uid = url.toExternalForm().replace(FILE_SEPARATOR, '\u0000')
+ "\u0000"
+ timeToString( connection.getLastModified() );
// Add the uid as a field, so that index can be incrementally maintained.
// This field is not stored with document, it is indexed, but it is not
// tokenized prior to indexing.
addUnstoredKeywordField( document, "uid", uid );
InputStream input = null;
try
{
input = connection.getInputStream();
addContent( document, input,url.toExternalForm() );
}
finally
{
if( input != null )
{
input.close();
}
}
// return the document
return document;
}
/**
* This will get a lucene document from a PDF file.
*
* @param is The stream to read the PDF from.
*
* @return The lucene document.
*
* @throws IOException If there is an error parsing or indexing the document.
*/
public static Document getDocument( InputStream is ) throws IOException
{
LucenePDFDocument converter = new LucenePDFDocument();
return converter.convertDocument( is );
}
/**
* This will get a lucene document from a PDF file.
*
* @param file The file to get the document for.
*
* @return The lucene document.
*
* @throws IOException If there is an error parsing or indexing the document.
*/
public static Document getDocument( File file ) throws IOException
{
LucenePDFDocument converter = new LucenePDFDocument();
return converter.convertDocument( file );
}
/**
* This will get a lucene document from a PDF file.
*
* @param url The file to get the document for.
*
* @return The lucene document.
*
* @throws IOException If there is an error parsing or indexing the document.
*/
public static Document getDocument( URL url ) throws IOException
{
LucenePDFDocument converter = new LucenePDFDocument();
return converter.convertDocument( url );
}
/**
* This will add the contents to the lucene document.
*
* @param document The document to add the contents to.
* @param is The stream to get the contents from.
* @param documentLocation The location of the document, used just for debug messages.
*
* @throws IOException If there is an error parsing the document.
*/
private void addContent( Document document, InputStream is, String documentLocation ) throws IOException
{
PDDocument pdfDocument = null;
try
{
pdfDocument = PDDocument.load( is );
if( pdfDocument.isEncrypted() )
{
//Just try using the default password and move on
pdfDocument.decrypt( "" );
}
//create a writer where to append the text content.
StringWriter writer = new StringWriter();
if( stripper == null )
{
stripper = new PDFTextStripper();
}
else
{
stripper.resetEngine();
}
stripper.writeText( pdfDocument, writer );
// Note: the buffer to string operation is costless;
// the char array value of the writer buffer and the content string
// is shared as long as the buffer content is not modified, which will
// not occur here.
String contents = writer.getBuffer().toString();
StringReader reader = new StringReader( contents );
// Add the tag-stripped contents as a Reader-valued Text field so it will
// get tokenized and indexed.
addTextField( document, "contents", reader );
PDDocumentInformation info = pdfDocument.getDocumentInformation();
if( info != null )
{
addTextField( document, "Author", info.getAuthor() );
try
{
addTextField( document, "CreationDate", info.getCreationDate() );
}
catch( IOException io )
{
//ignore, bad date but continue with indexing
}
addTextField( document, "Creator", info.getCreator() );
addTextField( document, "Keywords", info.getKeywords() );
try
{
addTextField( document, "ModificationDate", info.getModificationDate() );
}
catch( IOException io )
{
//ignore, bad date but continue with indexing
}
addTextField( document, "Producer", info.getProducer() );
addTextField( document, "Subject", info.getSubject() );
addTextField( document, "Title", info.getTitle() );
addTextField( document, "Trapped", info.getTrapped() );
}
int summarySize = Math.min( contents.length(), 500 );
String summary = contents.substring( 0, summarySize );
// Add the summary as an UnIndexed field, so that it is stored and returned
// with hit documents for display.
addUnindexedField( document, "summary", summary );
}
catch( CryptographyException e )
{
throw new IOException( "Error decrypting document(" + documentLocation + "): " + e );
}
catch( InvalidPasswordException e )
{
//they didn't suppply a password and the default of "" was wrong.
throw new IOException(
"Error: The document(" + documentLocation +
") is encrypted and will not be indexed." );
}
finally
{
if( pdfDocument != null )
{
pdfDocument.close();
}
}
}
/**
* This will test creating a document.
*
* usage: java pdfparser.searchengine.lucene.LucenePDFDocument <pdf-document>
*
* @param args command line arguments.
*
* @throws IOException If there is an error.
*/
public static void main( String[] args ) throws IOException
{
if( args.length != 1 )
{
String us = LucenePDFDocument.class.getName();
System.err.println( "usage: java " + us + " <pdf-document>" );
System.exit( 1 );
}
System.out.println( "Document=" + getDocument( new File( args[0] ) ) );
}
}