Extract PDF File(s) from Adobe PDF Portfolio File Using iTextSharp Open Source PDF Library

Using iTextSharp open source PDF library, the below console application illustrates opening one or more PDF files (based on file path and file mask inputs) and extracting a desired single PDF file from each.

using iTextSharp.text.pdf;
using System;
using System.Collections.Generic;
using System.IO;

namespace PdfPortfolioSample
{
  class Program
  {
    static void Main(string[] args)
    {
      Console.Write("Enter source path: ");
      string sourcePath = Console.ReadLine();
      Console.Write("Enter file mask (e.g. *.pdf): ");
      string fileMask = Console.ReadLine();
      Console.Write("Recursive (y/n): ");
      bool recursive = Console.ReadLine().ToUpper() == "Y";
      Console.Write("Enter target path: ");
      string targetPath = Console.ReadLine();
      Console.Write("Enter document name to extract (e.g. MLPA.PDF): ");
      string docName = Console.ReadLine();
      List<string> files = GetFiles(sourcePath, fileMask, recursive);
      foreach (string file in files)
      {
        GetPdfFromPortfolio(file, targetPath, docName);
      }
    }
    private static void GetPdfFromPortfolio(string filePath, string targetPath, string docName)
    {
      PdfReader reader = new PdfReader(filePath);
      PdfDictionary root = reader.Catalog;
      PdfDictionary documentnames = root.GetAsDict(PdfName.NAMES);
      PdfDictionary embeddedfiles =
          documentnames.GetAsDict(PdfName.EMBEDDEDFILES);
      PdfArray filespecs = embeddedfiles.GetAsArray(PdfName.NAMES);
      for (int i = 0; i < filespecs.Size;)
      {
        filespecs.GetAsString(i++);
        PdfDictionary filespec = filespecs.GetAsDict(i++);
        PdfDictionary refs = filespec.GetAsDict(PdfName.EF);
        foreach (PdfName key in refs.Keys)
        {
          PRStream stream = (PRStream)PdfReader.GetPdfObject(
            refs.GetAsIndirectObject(key)
          );

          if (filespec.GetAsString(key).ToString().ToUpper() == docName.ToUpper())
            using (FileStream fs = new FileStream(
              targetPath + @"\" + Path.GetFileName(filePath).Substring(0, 10) + filespec.GetAsString(key).ToString(), FileMode.OpenOrCreate
            ))
            {
              byte[] attachment = PdfReader.GetStreamBytes(stream);
              fs.Write(attachment, 0, attachment.Length);
            }
        }
      }

    }
    private static List<string> GetFiles(string path, string fileMask = "", bool recursive = false, List<string> files = null)
    {
      if (files == null) files = new List<string>();
      try
      {
        foreach (var file in Directory.GetFiles(path, fileMask))
        {
          files.Add(file);
        }
        if (recursive)
          foreach (string dir in Directory.GetDirectories(path))
          {
            GetFiles(dir, fileMask, recursive, files);
          }
      }
      catch (System.Exception e)
      {
        Console.WriteLine(e.ToString());
      }
      return files;
    }
  }
}