Stackoverflow Exception converting from docx

Technical Support Apryse SDK
1

Hi,

I am hitting a stackoverflow exception inside the TryConvert() call when trying to convert a docx file using the following code :

private static PDFDoc GeneratePDF(MemoryStream docStream)
        {
            var pdfDoc = new PDFDoc();
            pdfDoc.InitSecurityHandler();

            try
            {
                docStream.Seek(0, SeekOrigin.Begin);
                var streamBytes = docStream.ToArray();

                using (var memoryFilter = new MemoryFilter(0, false))
                using (var filterWriter = new FilterWriter(memoryFilter))
                {
                    filterWriter.WriteBuffer(streamBytes);
                    filterWriter.FlushAll();

                    var conversion = pdftron.PDF.Convert.WordToPDFConversion(pdfDoc, memoryFilter, null);
                    var result = conversion.TryConvert();

                    if (result != DocumentConversionResult.e_document_conversion_success)
                    {
                        throw new InvalidOperationException(conversion.GetErrorString());
                    }
                }
            }
            catch (Exception ex)
            {
                pdfDoc.Dispose();
                throw ex;
            }

            return pdfDoc;
        }

PDFNet version 6.8.56.6513
This seems to be true of any docx containing an image.
It only seems to be happening when PDFNet is running on a webserver (IIS)
I put together a Console Project to recreate it and the conversion works without any issues. Same code, same docx, same PDFNet version. It always fails on the webserver.

It's a stackoverflow so I've got very little to go on in the exception itself and obviously I've got no insight into what's happening in the TryConvert() method.

Any ideas?

Thanks,

Andrew

2

The issue is that IIS defaults to 256KB which is too small for this type of document conversion.
https://support.microsoft.com/en-us/help/932909/by-default-the-maximum-stack-size-of-a-thread-that-is-created-in-a-nat
https://blogs.msdn.microsoft.com/tom/2008/03/31/stack-sizes-in-iis-affects-asp-net/

Please increase the default size to something higher, e.g. 1MB.

3

Hi @Ryan, i’m using flask, i got the file FileStorage from request form-data. How can I parse FileStorage to MemoryStream? i need that for converting to pdf file like this post. Thank you