get_attachments
Extract the text from the document and recursively from all embedded PDF attachments.
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import java.io.PrintStream;
import java.io.UnsupportedEncodingException;
import com.pdflib.TET;
import com.pdflib.TETException;
/**
* Extract the text from the document and recursively from all embedded PDF
* attachments.
* <p>
* Required software: TET 3
* <p>
* Required data: PDF document
*
* @version $Id: get_attachments.java,v 1.3 2008/11/20 08:06:39 stm Exp $
*/
public class get_attachments
{
/**
* Global option list. The program expects the "resource" directory parallel
* to the "java" directory.
*/
static final String GLOBAL_OPTLIST = "searchpath={../resource/cmap "
+ "../resource/glyphlist ../input}";
/**
* Document specific option list.
*/
static final String DOC_OPTLIST = "";
/**
* Page-specific option list.
*/
static final String PAGE_OPTLIST = "granularity=page";
/**
* The encoding in which the output is sent to System.out. For running
* the example in a Windows command window, you can set this for example to
* "windows-1252" for getting Latin-1 output.
*/
private static final String OUTPUT_ENCODING =
System.getProperty("file.encoding");
/**
* For printing to System.out in the encoding specified via OUTPUT_ENCODING.
*/
private static PrintStream out;
/**
* Separator to emit after each chunk of text. This depends on the
* application's needs; for granularity=word a space character may be
* useful.
*/
static final String SEPARATOR = "\n";
/**
* Extract text from a document for which a TET handle is already available.
*
* @param tet
* The TET object
* @param doc
* A valid TET document handle
*
* @throws TETException
* An error occurred in the TET API
*/
static void extract_text(TET tet, int doc) throws TETException {
/*
* Get number of pages in the document.
*/
int n_pages = (int) tet.pcos_get_number(doc, "length:pages");
/* loop over pages */
for (int pageno = 1; pageno <= n_pages; ++pageno) {
String text;
int page;
page = tet.open_page(doc, pageno, PAGE_OPTLIST);
if (page == -1) {
System.err.println("Error " + tet.get_errnum() + " in "
+ tet.get_apiname() + "() on page " + pageno + ": "
+ tet.get_errmsg());
continue; /* try next page */
}
/*
* Retrieve all text fragments; This loop is actually not required
* for granularity=page, but must be used for other granularities.
*/
while ((text = tet.get_text(page)) != null) {
out.print(text); // print the retrieved text
/* print a separator between chunks of text */
out.print(SEPARATOR);
}
if (tet.get_errnum() != 0) {
System.err.println("Error " + tet.get_errnum() + " in "
+ tet.get_apiname() + "() on page " + pageno + ": "
+ tet.get_errmsg());
}
tet.close_page(page);
}
}
/**
* Open a named physical or virtual file, extract the text from it, search
* for document or page attachments, and process these recursively. Either
* filename must be supplied for physical files, or data+length from which a
* virtual file will be created. The caller cannot create the PVF file since
* we create a new TET object here in case an exception happens with the
* embedded document - the caller can happily continue with his TET object
* even in case of an exception here.
*
* @param filename
* The filename for an input file on disk (can be null)
* @param attachmentname
* The name of the attachment for displaying it to the user
* @param data
* Data of a PDF document loaded in memory (can be null)
*
* @return 0 if successful, otherwise a non-null code to be used as exit
* status
*/
static int process_document(String filename, String attachmentname,
byte[] data) {
int retval = 0;
TET tet = null;
try {
final String pvfname = "/pvf/attachment";
tet = new TET();
/*
* Construct a PVF file if data instead of a filename was provided
*/
if (filename == null || filename.length() == 0) {
tet.create_pvf(pvfname, data, "");
filename = pvfname;
}
tet.set_option(GLOBAL_OPTLIST);
int doc = tet.open_document(filename, DOC_OPTLIST);
if (doc == -1) {
System.err.println("Error " + tet.get_errnum() + " in "
+ tet.get_apiname() + "() (source: attachment '"
+ attachmentname + "'): " + tet.get_errmsg());
retval = 5;
}
else {
process_document(tet, doc);
}
/*
* If there was no PVF file deleting it won't do any harm
*/
tet.delete_pvf(pvfname);
}
catch (TETException e) {
System.err.println("Error " + e.get_errnum() + " in "
+ e.get_apiname() + "() (source: attachment '" + attachmentname
+ "'): " + e.get_errmsg());
retval = 1;
}
finally {
if (tet != null) {
tet.delete();
}
}
return retval;
}
/**
* Process a single file.
*
* @param tet
* The TET object
* @param doc
* The TET document handle
*
* @throws TETException
* An error occurred in the TET API.
*/
private static void process_document(TET tet, int doc) throws TETException {
String objtype;
// -------------------- Extract the document's own page contents
extract_text(tet, doc);
// -------------------- Process all document-level file attachments
// Get the number of document-level file attachments.
int filecount = (int) tet.pcos_get_number(doc,
"length:names/EmbeddedFiles");
for (int file = 0; file < filecount; file++) {
String attname;
/*
* fetch the name of the file attachment; check for Unicode file
* name (a PDF 1.7 feature)
*/
objtype = tet.pcos_get_string(doc, "type:names/EmbeddedFiles["
+ file + "]/UF");
if (objtype.equals("string")) {
attname = tet.pcos_get_string(doc, "names/EmbeddedFiles["
+ file + "]/UF");
}
else {
objtype = tet.pcos_get_string(doc, "type:names/EmbeddedFiles["
+ file + "]/F");
if (objtype.equals("string")) {
attname = tet.pcos_get_string(doc, "names/EmbeddedFiles["
+ file + "]/F");
}
else {
attname = "(unnamed)";
}
}
/* fetch the contents of the file attachment and process it */
objtype = tet.pcos_get_string(doc, "type:names/EmbeddedFiles["
+ file + "]/EF/F");
if (objtype.equals("stream")) {
out.println("----- File attachment '" + attname + "':");
byte attdata[] = tet.pcos_get_stream(doc, "",
"names/EmbeddedFiles[" + file + "]/EF/F");
process_document(null, attname, attdata);
out.println("----- End file attachment '" + attname + "'");
}
}
// -------------------- Process all page-level file attachments
int pagecount = (int) tet.pcos_get_number(doc, "length:pages");
// Check all pages for annotations of type FileAttachment
for (int page = 0; page < pagecount; page++) {
int annotcount = (int) tet.pcos_get_number(doc, "length:pages["
+ page + "]/Annots");
for (int annot = 0; annot < annotcount; annot++) {
String val;
String attname;
val = tet.pcos_get_string(doc, "pages[" + page + "]/Annots["
+ annot + "]/Subtype");
attname = "page " + (page + 1) + ", annotation " + (annot + 1);
if (val.equals("FileAttachment")) {
String attpath = "pages[" + page + "]/Annots[" + annot
+ "]/FS/EF/F";
/*
* fetch the contents of the attachment and process it
*/
objtype = tet.pcos_get_string(doc, "type:" + attpath);
if (objtype.equals("stream")) {
out.println("----- Page level attachment '" + attname + "':");
byte attdata[] = tet.pcos_get_stream(doc, "", attpath);
process_document(null, attname, attdata);
out.println("----- End page level attachment '" + attname + "':");
}
}
}
}
tet.close_document(doc);
}
public static void main(String[] args) throws UnsupportedEncodingException {
int ret = 0;
System.out.println("Using output encoding \"" + OUTPUT_ENCODING + "\"");
out = new PrintStream(System.out, true, OUTPUT_ENCODING);
if (args.length != 1) {
System.err.println("usage: get_attachments <infilename>");
System.exit(2);
}
try {
ret = process_document(args[0], args[0], null);
}
catch (Exception e) {
e.printStackTrace();
ret = 1;
}
System.exit(ret);
}
}