Syncfusion PdfViewerControl on Azure - image

Question

I am utilizing Syncfusion's PdfViewerControl and PdfLoadedDocument classes to generate thumbnail images of a PDF. However, once I moved the project to an Azure App Service, the PdfViewerControl is throwing an exception when being initialized. I am curious if it is attempting to use system memory and Azure is blocking this. Below is the method GenerateThumbnails I've created and the exception is being thrown when creating a new PdfViewerControl. If anyone has a work around for this or has experienced something similar when moving to Azure, any assistance would be greatly appreciated.
Along with that, if someone knows of another tool to create thumbnails from a PDF in this manner that'd be very helpful as well. Thanks!
Exception:
System.AccessViolationException: 'Attempted to read or write protected memory. This is often an indication that other memory is corrupt.'
Method:
public static List<Byte[]> GenerateThumbnails(Byte[] file)
{
Int32 resizedHeight;
Int32 resizedWidth;
List<Byte[]> thumbnails = new List<Byte[]>();
using (PdfViewerControl pdfViewerControl = new PdfViewerControl())
using (PdfLoadedDocument pdfLoadedDocument = new PdfLoadedDocument(file, true))
{
// The PDF Viewer Control must load the PDF from a PdfLoadedDocument, rather than directly from the filename because
// when loaded from the filename, it is not disposed correctly and causes a file lock.
pdfViewerControl.Load(pdfLoadedDocument);
for (Int32 i = 0; i < pdfViewerControl.PageCount; ++i)
{
using (Bitmap originalBitmap = pdfViewerControl.ExportAsImage(i))
{
if (pdfViewerControl.LoadedDocument.Pages[i].Size.Width > pdfViewerControl.LoadedDocument.Pages[i].Size.Height)
{
resizedHeight = (PdfUtility.TARGET_THUMBNAIL_WIDTH_LANDSCAPE * originalBitmap.Height) / originalBitmap.Width;
resizedWidth = PdfUtility.TARGET_THUMBNAIL_WIDTH_LANDSCAPE;
}
else
{
resizedHeight = PdfUtility.TARGET_THUMBNAIL_HEIGHT_PORTRAIT;
resizedWidth = (PdfUtility.TARGET_THUMBNAIL_HEIGHT_PORTRAIT * originalBitmap.Width) / originalBitmap.Height;
}
using (Bitmap resizedBitmap = new Bitmap(originalBitmap, new Size(resizedWidth, resizedHeight)))
using (MemoryStream memoryStream = new MemoryStream())
{
resizedBitmap.Save(memoryStream, ImageFormat.Jpeg);
thumbnails.Add(memoryStream.ToArray());
}
}
}
}
return thumbnails;
}

Answer 1

Update
Web App for Containers on Windows is now supported. This allows you to bring your own docker container that runs outside of the sandbox, so the restrictions described below won't affect your application.
There are restrictions in the sandbox that the app is running in that prevents certain API calls.
Here is a list of frameworks and scenarios that have been found to be
not be usable due to one or more of the restrictions above. It's
conceivable that some will be supported in the future as the sandbox
evolves.
PDF generators failing due to restriction mentioned above:
Syncfusion Siberix Spire.PDF The following PDF generators are
supported:
SQL Reporting framework: requires the site to run in Basic or higher
(note that this currently does not work in Functions apps in
Consumptions mode) EVOPDF: See
http://www.evopdf.com/azure-html-to-pdf-converter.aspx for vendor
solution Telerik reporting: requires the site to run in Basic or
higher. More info here Rotativa / wkhtmltopdf: requires the site to
run in Basic or higher. NReco PdfGenerator (wkhtmltopdf): requires
subscription plan Basic or higher Known issue for all PDF generators
based on wkhtmltopdf or phantomjs: custom fonts are not rendered
(system-installed font is used instead) because of sandbox GDI API
limitations that present even in VM-based Azure Apps plans (Basic or
higher).
Other scenarios that are not supported:
PhantomJS/Selenium: tries to connect to local address, and also uses
GDI+.
https://github.com/projectkudu/kudu/wiki/Azure-Web-App-sandbox