[TIKA-679] Proposal for PRT Parser

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Component/s: mime, parser
• Labels: CAD Mime Parser Prt Tika
• Assignee: Unassigned
• Reporter: Troy Witthoeft
• Created: 22/Jun/11 16:44
• Updated: 08/Nov/11 18:17
• Resolved: 08/Nov/11 18:17

Description

It would be nice if Tika had support for prt CAD files.
A preliminary prt text extractor has been created.
Any assistance further developing this code is appreciated.

PRTParser.java

package org.apache.tika.parser.prt;

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.UnsupportedEncodingException;
import java.nio.charset.Charset;
import java.util.Collections;
import java.util.Set;

import org.apache.poi.util.IOUtils;
import org.apache.tika.exception.TikaException;
import org.apache.tika.metadata.Metadata;
import org.apache.tika.mime.MediaType;
import org.apache.tika.parser.ParseContext;
import org.apache.tika.parser.Parser;
import org.apache.tika.sax.XHTMLContentHandler;
import org.xml.sax.ContentHandler;
import org.xml.sax.SAXException;

/**
 * Description: PRT (CAD Drawing) parser. This is a very basic parser.   
 * Searches for specific byte prefix, and outputs text from note entities.
 * Does not support special characters.
 */
 

public class PRTParser implements Parser {

    private static final Set<MediaType> SUPPORTED_TYPES = Collections.singleton(MediaType.application("prt"));
    public static final String PRT_MIME_TYPE = "application/prt";
        	
    public Set<MediaType> getSupportedTypes(ParseContext context) {
        return SUPPORTED_TYPES;
        }
		
    public void parse(
		InputStream stream, ContentHandler handler,
		Metadata metadata, ParseContext context)
		throws IOException, SAXException, TikaException {
		XHTMLContentHandler xhtml = new XHTMLContentHandler(handler, metadata);
		
		int[] prefix = new int[] {227, 63};  				//Looking for a prefix set of bytes {E3, 3F} 
		int pos = 0;										//position inside the prefix
		int read;
		while( (read = stream.read()) > -1) {					// stream.read() moves to the next byte, and returns an integer value of the byte.  a value of -1 signals the EOF
			if(read == prefix[pos]) {								// is the last byte read the same as the first byte in the prefix?
				pos++;													
					if(pos == prefix.length) {								//Are we at the last position of the prefix?
						stream.skip(11);										// skip the 11 bytes of the prefix which can vary.
						int lengthbyte = stream.read();							// Set the next byte equal to the length of text in the user input field, see PRT schema
						stream.skip(1);											
						byte[] text = new byte[lengthbyte];						// a new byte array called text is created.  It should contain an array of integer values of the user inputted text.
						IOUtils.readFully(stream, text);						
						String str = new String(text, 0, text.length, "Cp437");	// Cp437 turn it into a string, but does not remove null termination, assumes it's found to be MS-DOS Encoding
						str = str.replace("\u03C6","\u00D8");					// Note: Substitute CP437's lowercase "phi" for Nordic "O with slash" to represent diameter symbol. 
						metadata.add("Content",str);
						xhtml.startElement("p");	
						xhtml.characters(str);
						xhtml.endElement("p");
						pos = 0; 							
					}
			} 
			else {
				//Did not find the prefix. Reset the position counter.
				pos = 0;
			}
		}
	//Reached the end of file
	//System.out.println("Finished searching the file");	
	}


		
	/**
    * @deprecated This method will be removed in Apache Tika 1.0.
    */
    public void parse(
                   InputStream stream, ContentHandler handler, Metadata metadata)
                   throws IOException, SAXException, TikaException {
                parse(stream, handler, metadata, new ParseContext());
    }
}