Validate PDF/check startxref

[digitaldirk]

Hi,

What are ways you can check if a PDF is valid/or check if the startxref exists?

My case:
I get a list of base64 pdf strings, I then make a list of byte[], then I use PdfMerger.Merge() to combine them all, which works great until one of the PDFs is bad.

Only on certain pdfs the merge call throws: UglyToad.PdfPig.Core.PdfDocumentFormatException: 'Could not find the startxref within the last 2048 characters.'

I sadly cannot give the base64 data in question due to personal data.

Thank you for your time

[digitaldirk]

Simple solution to my issue:
I got the bytes of the base64 string then decoded the bytes into the raw string of the PDF, then checked if the raw PDF string contained startxref.

var bytes = Convert.FromBase64String(base64input);
string rawPDF = Encoding.UTF8.GetString(bytes);
if (rawPDF.Contains("startxref"))
{
...
}

Maybe an option to skip bad PDF's could be added to the Merge call?