Reading attachment from a secured PDF - pdf

Question

I am working on a PDF file, which is a secured one and an excel is attached in the PDF file.
The following is the code i tried.
static void Main(string[] args)
{
Program pgm = new Program();
pgm.EmbedAttachments();
//pgm.ExtractAttachments(pgm.pdfFile);
}
private void ExtractAttachments(string _pdfFile)
{
try
{
if (!Directory.Exists(attExtPath))
Directory.CreateDirectory(attExtPath);
byte[] password = System.Text.ASCIIEncoding.ASCII.GetBytes("TFAER13052016");
//byte[] password = System.Text.ASCIIEncoding.ASCII.GetBytes("Password");
PdfDictionary documentNames = null;
PdfDictionary embeddedFiles = null;
PdfDictionary fileArray = null;
PdfDictionary file = null;
PRStream stream = null;
//PdfReader reader = new PdfReader(_pdfFile);
PdfReader reader = new PdfReader(_pdfFile, password);
PdfDictionary catalog = reader.Catalog;
documentNames = (PdfDictionary)PdfReader.GetPdfObject(catalog.Get(PdfName.NAMES));
if (documentNames != null)
{
embeddedFiles = (PdfDictionary)PdfReader.GetPdfObject(documentNames.Get(PdfName.EMBEDDEDFILES));
if (embeddedFiles != null)
{
PdfArray filespecs = embeddedFiles.GetAsArray(PdfName.NAMES);
for (int i = 0; i < filespecs.Size; i++)
{
i++;
fileArray = filespecs.GetAsDict(i);
file = fileArray.GetAsDict(PdfName.EF);
foreach (PdfName key in file.Keys)
{
stream = (PRStream)PdfReader.GetPdfObject(file.GetAsIndirectObject(key));
string attachedFileName = fileArray.GetAsString(key).ToString();
byte[] attachedFileBytes = PdfReader.GetStreamBytes(stream);
System.IO.File.WriteAllBytes(attExtPath + attachedFileName, attachedFileBytes);
}
}
}
else
throw new Exception("Unable to Read the attachment or There may be no Attachment");
}
else
{
throw new Exception("Unable to Read the document");
}
}
catch (Exception ex)
{
Console.WriteLine(ex.ToString());
Console.ReadKey();
}
}
private void EmbedAttachments()
{
try
{
if (File.Exists(pdfFile))
File.Delete(pdfFile);
Document PDFD = new Document(PageSize.LETTER);
PdfWriter writer;
writer = PdfWriter.GetInstance(PDFD, new FileStream(pdfFile, FileMode.Create));
PDFD.Open();
PDFD.NewPage();
PDFD.Add(new Paragraph("This is test"));
PdfFileSpecification pfs = PdfFileSpecification.FileEmbedded(writer, #"C:\PDFReader\1.xls", "11.xls", null);
//PdfFileSpecification pfs = PdfFileSpecification.FileEmbedded(writer, attFile, "11", File.ReadAllBytes(attFile), true);
writer.AddFileAttachment(pfs);
//writer.AddAnnotation(PdfAnnotation.CreateFileAttachment(writer, new iTextSharp.text.Rectangle(100, 100, 100, 100), "File Attachment", PdfFileSpecification.FileExtern(writer, "C:\\test.xml")));
//writer.Close();
PDFD.Close();
Program pgm=new Program();
using (Stream input = new FileStream(pgm.pdfFile, FileMode.Open, FileAccess.Read, FileShare.Read))
{
using (Stream output = new FileStream(pgm.epdfFile, FileMode.Create, FileAccess.Write, FileShare.None))
{
PdfReader reader = new PdfReader(input);
PdfEncryptor.Encrypt(reader, output, true, "Password", "secret", PdfWriter.ALLOW_SCREENREADERS);
}
}
}
catch (Exception ex)
{
Console.WriteLine(ex.StackTrace.ToString());
Console.ReadKey();
}
}
}
The above code contains the creation of a encrypted PDF with an excel attachment and also to extract the same.
Now the real problem is with the file which I already have as a requirement document(I cannot share the file) which also has an excel attachment like my example.
But the above code works for the secured PDF which i have created but not for the actual Secured PDF.
While debugging, I found that the Issue is with the following code
documentNames = (PdfDictionary)PdfReader.GetPdfObject(catalog.Get(PdfName.NAMES));
In which,
catalog.Get(PdfName.NAMES)
is returned as NULL, Where as the File created by me, provides the expected output.
Please guide me on the above.
TIA.

Answer 1

As mkl suggested, It has been attached as an Annotated attachment. But the reference which is used in the example is provided ZipFile Method is no longer supported. Hence I found an alternate code attached below.
public void ExtractAttachments(byte[] src)
{
PRStream stream = null;
string attExtPath = #"C:\PDFReader\Extract\";
if (!Directory.Exists(attExtPath))
Directory.CreateDirectory(attExtPath);
byte[] password = System.Text.ASCIIEncoding.ASCII.GetBytes("TFAER13052016");
PdfReader reader = new PdfReader(src, password);
for (int i = 1; i <= reader.NumberOfPages; i++)
{
PdfArray array = reader.GetPageN(i).GetAsArray(PdfName.ANNOTS);
if (array == null) continue;
for (int j = 0; j < array.Size; j++)
{
PdfDictionary annot = array.GetAsDict(j);
if (PdfName.FILEATTACHMENT.Equals(
annot.GetAsName(PdfName.SUBTYPE)))
{
PdfDictionary fs = annot.GetAsDict(PdfName.FS);
PdfDictionary refs = fs.GetAsDict(PdfName.EF);
foreach (PdfName name in refs.Keys)
{
//zip.AddEntry(
// fs.GetAsString(name).ToString(),
// PdfReader.GetStreamBytes((PRStream)refs.GetAsStream(name))
//);
stream = (PRStream)PdfReader.GetPdfObject(refs.GetAsIndirectObject(name));
string attachedFileName = fs.GetAsString(name).ToString();
var splitname = attachedFileName.Split('\\');
if (splitname.Length != 1)
attachedFileName = splitname[splitname.Length - 1].ToString();
byte[] attachedFileBytes = PdfReader.GetStreamBytes(stream);
System.IO.File.WriteAllBytes(attExtPath + attachedFileName, attachedFileBytes);
}
}
}
}
}
Please Let me Know if it can be achieved in any other way.
Thanks!!!