ASP.NET Core on Linux problem with itextsharp - asp.net-mvc

Question

We have a small ASP.NET Core 3.1 web app. We use itextsharp library (5.5.13) for generating a simple PDF and exporting it.
All works well in debug (and on Windows server), but when published on a Linux server (Debian 10) there is an error generating the PDF:
Error: The document has no pages.
Stack trace:
at iTextSharp.text.pdf.PdfPages.WritePageTree()
at iTextSharp.text.pdf.PdfWriter.Close()
at iTextSharp.text.pdf.PdfDocument.Close()
at iTextSharp.text.Document.Close()
at eDov.Web.Helpers.Reports.Dovolilnice.GetPdfTest() in C:\*\Reports\Dovolilnica.cs:line 173
at eDov.Web.Controllers.DovolilniceController.TestPdf(Int32 id) in C:\*\Controllers\DovolilniceController.cs:line 184
at lambda_method(Closure , Object , Object[] )
at Microsoft.Extensions.Internal.ObjectMethodExecutor.Execute(Object target, Object[] parameters)
at Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.SyncActionResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, Object controller, Object[] arguments)
at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeActionMethodAsync() at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeNextActionFilterAsync()
--- End of stack trace from previous location where exception was thrown ---
at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Rethrow(ActionExecutedContextSealed context)
at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeInnerFilterAsync()
--- End of stack trace from previous location where exception was thrown ---
at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Awaited|24_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ResourceExecutedContextSealed context)
at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.InvokeFilterPipelineAsync()
--- End of stack trace from previous location where exception was thrown ---
at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Awaited|17_0(ResourceInvoker invoker, Task task, IDisposable scope)
at Microsoft.AspNetCore.Routing.EndpointMiddleware.g__AwaitRequestTask|6_0(Endpoint endpoint, Task requestTask, ILogger logger)
at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context) at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)
at Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware.g__Awaited|6_0(ExceptionHandlerMiddleware middleware, HttpContext context, Task task)
The code from the controller that is called to generate the PDF:
public IActionResult TestPdf(int id)
{
var file = new Dokument
{
Naziv = string.Format("Dovolilnica - {0}.pdf", id.ToString()),
Extension = ".pdf",
ContentType = "application/pdf",
};
//this is the line that the error from stack trace is referring
file.Contents = Helpers.Reports.Dovolililnice.GetPdfTest();
return File(file.Contents, file.ContentType, file.Naziv);
}
and the code that generates the PDF:
public static byte[] GetPdfTest()
{
byte[] result = null;
// custom velikost nalepke
// 1 inch = 72px
var pgSize = new iTextSharp.text.Rectangle(176f, 135f);
MemoryStream pdfData = new MemoryStream();
iTextSharp.text.Document document = new iTextSharp.text.Document(pgSize, 7.5f, 7.5f, 7.5f, 7.5f);
PdfWriter pdfWriter = PdfWriter.GetInstance(document, pdfData);
pdfWriter.ViewerPreferences = PdfWriter.PageModeUseOutlines;
document.Open();
document.Add(new Paragraph("Create test Pdf Document"));
pdfWriter.CloseStream = false;
document.Close();
//this is the line that the error from stack trace is referring
pdfData.Position = 0;
result = pdfData.ToArray();
pdfData.Dispose();
return result;
}
Has anyone used itextsharp (lower than version 7) successfully when publishing on Linux?

Answer 1

We couldn't get this working on Linux so we tried using iTextSharp.LGPLv2.Core port of the itextsharp library (see: https://github.com/VahidN/iTextSharp.LGPLv2.Core) and it works.
It's also available in Nuget PM.