Tika--Extracting Distinct Items from a Compound Document - apache-tika

Question

Question:
Assume an email message with an attachment (assume a JPEG attachment). How do I parse (not using the Tika facade classes) the email message and return the distinct pieces--a) the email text contents and b) the email attachment?
Configuration:
Tika 1.2
Java 1.7
Details:
I have been able to properly parse email messages in basic email message formats. However, after the parsing, I need to know a) the email's text contents and b) the the contents of any attachment to the email. I will store these items in my database as essentially parent email with child attachments.
What I cannot figure out is how I can "get back" the distinct parts and know that the parent email has attachments and be able to separately store those attachments referenced to the mail. This is, I believe, essentially similar to extracting ZipFile contents.
Code Example:
private Message processDocument(String fullfilepath) {
try {
File filename = new File(fullfilepath) ;
return this.processDocument(filename) ;
} catch (NullPointerException npe) {
Message error = new Message(false) ;
error.appendErrorMessage("The file name was null.") ;
return error ;
}
}
private Message processDocument(File filename) {
InputStream stream = null;
try {
stream = new FileInputStream(filename) ;
} catch (FileNotFoundException fnfe) {
// TODO Auto-generated catch block
fnfe.printStackTrace();
System.out.println("FileNotFoundException") ;
return diag ;
}
int writelimit = -1 ;
ContentHandler texthandler = new BodyContentHandler(writelimit);
this.safehandlerbodytext = new SafeContentHandler(texthandler);
this.meta = new Metadata() ;
ParseContext context = new ParseContext() ;
AutoDetectParser autodetectparser = new AutoDetectParser() ;
try {
autodetectparser.parse(
stream,
texthandler,
meta,
context) ;
this.documenttype = meta.get("Content-Type") ;
diag.setSuccessful(true);
} catch (IOException ioe) {
// if the document stream could not be read
System.out.println("TikaTextExtractorHelper IOException " + ioe.getMessage()) ;
//FIXME -- add real handling
} catch (SAXException se) {
// if the SAX events could not be processed
System.out.println("TikaTextExtractorHelper SAXException " + se.getMessage()) ;
//FIXME -- add real handling
} catch (TikaException te) {
// if the document could not be parsed
System.out.println("TikaTextExtractorHelper TikaException " + te.getMessage()) ;
System.out.println("Exception Filename = " + filename.getName()) ;
//FIXME -- add real handling
}
}

Answer 1

When Tika hits an embedded document, it goes to the ParseContext to see if you have supplied a recursing parser. If you have, it'll use that to process any embedded resources. If you haven't, it'll skip.
So, what you probably want to do is something like:
public static class HandleEmbeddedParser extends AbstractParser {
public List<File> found = new ArrayList<File>();
Set<MediaType> getSupportedTypes(ParseContext context) {
// Return what you want to handle
HashSet<MediaType> types = new HashSet<MediaType>();
types.put(MediaType.application("pdf"));
types.put(MediaType.application("zip"));
return types;
}
void parse(
InputStream stream, ContentHandler handler,
Metadata metadata, ParseContext context
) throws IOException {
// Do something with the child documents
// eg save to disk
File f = File.createTempFile("tika","tmp");
found.add(f);
FileOutputStream fout = new FileOutputStream(f);
IOUtils.copy(stream,fout);
fout.close();
}
}
ParseContext context = new ParseContext();
context.set(Parser.class, new HandleEmbeddedParser();
parser.parse(....);