Does PDF file contain iref stream?

问题

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.

回答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:

download and include the iTextSharp 4.1.6 library
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;
        }
    }
}

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

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

回答2:

PDFsharp 1.32 and earlier did not support iref streams.

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

回答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.

回答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)
{
    //
}

来源：https://stackoverflow.com/questions/12782295/does-pdf-file-contain-iref-stream

标签

pdf

pdfsharp