Does PDF file contain iref stream?

Question

I still fight with read data from PDF file.
I use PDFsharp, how can I check if file contains iref stream without use method Open. Method Open throws exception if file contains iref stream.

Parquet

I have no idea about PDF#, but my solution would be to open the PDF and fetch the specific exception – Peterkin

a new version of pdfsharp is available It's still a beta version: 1.50.4000-beta3b but it solves the issue. You can download it from nuget nuget.org/packages/PdfSharp/1.50.4000-beta3b – Cinchonize

Answer 1

There is a know workaround to permit you to open ALSO the pdf files that contains iref: you can find here the complete thread about that.

Just to summarize the solution:

1. download and include the iTextSharp 4.1.6 library
2. paste the following code in a code file into your project:

-

using System;
using System.IO;

namespace PdfSharp.Pdf.IO
{
    static public class CompatiblePdfReader
    {
        /// <summary>
        /// uses itextsharp 4.1.6 to convert any pdf to 1.4 compatible pdf, called instead of PdfReader.open
        /// </summary>
        static public PdfDocument Open(string pdfPath)
        {
            using (var fileStream = new FileStream(pdfPath, FileMode.Open, FileAccess.Read))
            {
                var len = (int)fileStream.Length;
                var fileArray = new Byte[len];
                fileStream.Read(fileArray, 0, len);
                fileStream.Close();

                return Open(fileArray);
            }
        }

        /// <summary>
        /// uses itextsharp 4.1.6 to convert any pdf to 1.4 compatible pdf, called instead of PdfReader.open
        /// </summary>
        static public PdfDocument Open(byte[] fileArray)
        {
            return Open(new MemoryStream(fileArray));
        }

        /// <summary>
        /// uses itextsharp 4.1.6 to convert any pdf to 1.4 compatible pdf, called instead of PdfReader.open
        /// </summary>
        static public PdfDocument Open(MemoryStream sourceStream)
        {
            PdfDocument outDoc;
            sourceStream.Position = 0;

            try
            {
                outDoc = PdfReader.Open(sourceStream, PdfDocumentOpenMode.Import);
            }
            catch (PdfReaderException)
            {
                //workaround if pdfsharp doesn't support this pdf
                sourceStream.Position = 0;
                var outputStream = new MemoryStream();
                var reader = new iTextSharp.text.pdf.PdfReader(sourceStream);
                var pdfStamper = new iTextSharp.text.pdf.PdfStamper(reader, outputStream) {FormFlattening = true};
                pdfStamper.Writer.SetPdfVersion(iTextSharp.text.pdf.PdfWriter.PDF_VERSION_1_4);
                pdfStamper.Writer.CloseStream = false;
                pdfStamper.Close();

                outDoc = PdfReader.Open(outputStream, PdfDocumentOpenMode.Import);
            }

            return outDoc;
        }
    }
}

3. Change all your calls to PdfReader.Open to CompatiblePdfReader.Open.

It works like a charm for me, hope this helps you.

Jonette

Until you get exception: PdfReader not opened with owner password. I still have not overcome this one. I think you can use an older (pre 4.0.4) version of iTextSharp. – Dunnite

Wish I could upvote this more times! So simple when you know how!! – Sacramentalist

this was a life saver! I had a need to merge generated PDFs with some provided PDFs that I didn't have control over. This solution let me use both and be able to merge them without throwing out the incompatible ones. – Donothing

The answer looks good - however it's worth noting that iTextSharp uses the AGPL and so for most commercial operations a license fee will be payable. – Chlorite

@StuartMoore the linked version is under MPL / LGPLv2 – Jonette

Answer 2

PDFsharp 1.32 and earlier did not support iref streams.

Since December 2015 we have PDFsharp 1.50 with support for iref streams.

Bibliotaph

As of writing this you need to select the pre-release version from NuGet... – Geer

1.50.3638-beta has other issue with PdfReader.Open() hangs. It is not fixed and still present in version 1.50.4000-beta3b, which is the last one currently. See Bug: PdfReader.Open() (PDFsharp 1.5) thread. – Pertinacious

Answer 3

Although a late reply but might be useful.

I am on a same situation (C# Project using pdfSharp). I've a PowerShell script, which ignores the files with iref stream while merging (Thus not throwing the exception).

Function Merge-PDF {
    Param($path, $filename)                        



    $output = New-Object PdfSharp.Pdf.PdfDocument
    $PdfReader = [PdfSharp.Pdf.IO.PdfReader]
    $PdfDocumentOpenMode = [PdfSharp.Pdf.IO.PdfDocumentOpenMode]                        

    foreach($i in (gci $path *.pdf -Recurse)) {
        $input = New-Object PdfSharp.Pdf.PdfDocument
        $input = $PdfReader::Open($i.fullname, $PdfDocumentOpenMode::Import)
        $input.Pages | %{$output.AddPage($_)}
    }                        

    $output.Save($filename)
}

Merge-PDF -path c:\reports -filename c:\reports\zzFull_deck.pdf

Will definitely post the C# equivalent of above function later.

Meliamelic

And he never returned. – Mitchum

Handling PdfSharp.Pdf.IO.PdfReaderException with an empty catch block did the trick. – Meliamelic

Answer 4

The work around is to catch the PdfSharp.Pdf.IO.PdfReaderException, and ignore the files causing such exceptions.

PdfDocument inputPDFDocument = new PdfDocument();
try
{
    inputPDFDocument = PdfReader.Open(pdfFile, PdfDocumentOpenMode.Import);
}
catch (PdfSharp.Pdf.IO.PdfReaderException)
{
    //
}

Meliamelic

just ignore them? like just ignoring some of my job requirements? yea sounds like a fix – Boult

@Boult that indeed was the case. Check Vive la deraison's answer for the solution in newer versions of PDFsharp. – Meliamelic