ClosedXML doesn't work within AWS Lambda Serverless App

• Bug

Version of ClosedXML 0.94.2

What is the current behavior?

ASP .NET Core Web API hosted on AWS Lambda using ClosedXML to create an Excel file fails with an exception:

System.DllNotFoundException: Unable to load shared library ‘libdl’ or one of its dependencies

Exception stack trace:

System.TypeInitializationException: The type initializer for 'Gdip' threw an exception. ---> System.DllNotFoundException: Unable to load shared library 'libdl' or one of its dependencies. In order to help diagnose loading problems, consider setting the LD_DEBUG environment variable: liblibdl: cannot open shared object file: No such file or directory
   at IntPtr Interop+Libdl.dlopen(string fileName, int flag)
   at IntPtr System.Drawing.SafeNativeMethods+Gdip.LoadNativeLibrary()
   at static System.Drawing.SafeNativeMethods+Gdip()
   --- End of inner exception stack trace ---
   at int System.Drawing.SafeNativeMethods+Gdip.GdipGetGenericFontFamilySansSerif(out IntPtr fontfamily)
   at IntPtr System.Drawing.FontFamily.GetGdipGenericSansSerif()
   at FontFamily System.Drawing.FontFamily.get_GenericSansSerif()
   at void System.Drawing.Font.CreateFont(string familyName, float emSize, FontStyle style, GraphicsUnit unit, byte charSet, bool isVertical)
   at Font ClosedXML.Excel.FontBaseExtensions.GetCachedFont(IXLFontBase fontBase, Dictionary<IXLFontBase, Font> fontCache)
   at double ClosedXML.Excel.FontBaseExtensions.GetWidth(IXLFontBase fontBase, string text, Dictionary<IXLFontBase, Font> fontCache)
   at IXLColumn ClosedXML.Excel.XLColumn.AdjustToContents(int startRow, int endRow, double minWidth, double maxWidth)
   at IXLColumns ClosedXML.Excel.XLColumns.AdjustToContents()+(XLColumn c) => { }
   at void System.Collections.Generic.List<T>.ForEach(Action<T> action)
   at IXLColumns ClosedXML.Excel.XLColumns.AdjustToContents()
   at IActionResult Api.Controllers.ValuesController.GetExcelClosedXml() in D:/agent01/w/8c3be5c345025092/src/Api/Controllers/ValuesController.cs:line 92
   at object lambda_method(Closure, object, object[])
   at object Microsoft.Extensions.Internal.ObjectMethodExecutor.Execute(object target, object[] parameters)
   at ValueTask<IActionResult> Microsoft.AspNetCore.Mvc.Internal.ActionMethodExecutor+SyncActionResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, object controller, object[] arguments)
   at async Task Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.InvokeActionMethodAsync()
   at async Task Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.InvokeNextActionFilterAsync()

What is the expected behavior or new feature?

It should… Just Work™ 😃

Did this work in previous versions of our tool? Which versions? Don’t know / probably not.

Reproducibility

[HttpGet]
public IActionResult GetExcelClosedXml()
{
    using (var workbook = new XLWorkbook())
    {
        var worksheet = workbook.Worksheets.Add("Items");
        worksheet.Cell("A1").Value = "Name";
        worksheet.Cell("B1").Value = "Value (%)";

        worksheet.Cell("A2").Value = "Item 1";
        worksheet.Cell("B2").Value = 0.35;
        worksheet.Cell("B2").Style.NumberFormat.Format = "0.00%";

        worksheet.Columns().AdjustToContents();

        var memoryStream = new MemoryStream();

        workbook.SaveAs(memoryStream);
        memoryStream.Seek(0, SeekOrigin.Begin);

        return File(memoryStream, contentType: "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
        fileDownloadName: "items.xlsx");
    }
}

[augustoproiete]

As for the file being corrupted, it seems very strange as the file you attached is not even considered a valid zip archive

Thanks. I’ll investigate further. It could be something else on AWS corrupting the file - i.e. not related to ClosedXML.

@Pankraty: Just to circle back on the corrupted file issue. As suspected, it is not related to ClosedXML. AWS’s API Gateway was corrupting the file by not treating it as binary.

For the benefit of people in the future that may find this issue via search, the fix was to set binary media types in AWS’s API Gateway for the file types I’m using:

• application/octet-stream
• application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
• multipart/form-data
• */*

[Lonli-Lokli]

Issue with Drawing on lambda can be fixed by adding two refs into net core project

1. https://www.nuget.org/packages/System.Drawing.Common/ >=4.5.0
2. https://www.nuget.org/packages/runtime.linux-x64.CoreCompat.System.Drawing/