OpenHtmlToPdf Access is denied with ASP.NET

Question

In my ASP.NET application (.NET Framework 4.7) I'm using OpenHtmlToPdf for creating PDF based on the pages in the website.

It is working locally but not in the server production: I have the following error:

Exception type: System.ComponentModel.Win32Exception Exception message: Access is denied

Stack trace: at System.Diagnostics.Process.StartWithCreateProcess(ProcessStartInfo startInfo) at System.Diagnostics.Process.Start() at System.Diagnostics.Process.Start(ProcessStartInfo startInfo) at OpenHtmlToPdf.HtmlToPdfConverterProcess.Convert(ConversionSource conversionSource) at OpenHtmlToPdf.Pdf.DocumentBuilder.ReadContentUsingTemporaryFile(String temporaryFilename)

I think the problem is related to wkhtmltopdf because OpenHtmlToPdf is using this library to generate the PDF. The code is pretty simple.

    var pdf = Pdf.From(html)
                 .WithGlobalSetting("orientation", "Landscape")
                 .WithObjectSetting("web.defaultEncoding", "utf-8")
                 .Content();

    return File(pdf, System.Net.Mime.MediaTypeNames.Application.Octet, "Reference.pdf");

Then, how can I generate the PDF?

In which folder are you trying to create that file? It seems to be the root of your site. Usually this folder is not writable. Did you try to create that file in the APP_DATA folder? — Steve

Espen Espen · Accepted Answer · 2019-10-27T13:28:09

OpenHTMLToPDF use Path.GetTempPath() and Guid.NewGuid() to create a temp file. Make sure your running process has sufficient privelegdes to write to the path returned by Path.GetTempPath();

For reference here is the source code responsible for creating the temp file name, and writing it.

//inside TemporaryPdf class
public static string TemporaryFilePath() 
{
  return Path.Combine(Path.GetTempPath(), "OpenHtmlToPdf", TemporaryPdf.TemporaryFilename());
}

private static string TemporaryFilename()
{
  return Guid.NewGuid().ToString("N") + ".pdf";
}

And then it is used when calling Content

  // inside the Pdf class
  public byte[] Content()
  {
    return this.ReadContentUsingTemporaryFile(TemporaryPdf.TemporaryFilePath());
  }

  private byte[] ReadContentUsingTemporaryFile(string temporaryFilename)
  {
    this._globalSettings["out"] = temporaryFilename;
    HtmlToPdfConverterProcess.ConvertToPdf(this._html, this._globalSettings, this._objectSettings);
    byte[] numArray = TemporaryPdf.ReadTemporaryFileContent(temporaryFilename);
    TemporaryPdf.DeleteTemporaryFile(temporaryFilename);
    return numArray;
  }

The rest of the code can be found on GitHub here: OpenHTMLToPDF

OpenHtmlToPdf Access is denied with ASP.NET

1 Answers