Process terminated. A callback was made on a garbage collected delegate of type 'WkHtmlToPdfDotNet ! WkHtmlToPdfDotNet. StringCallback: : Invoke'

[ninhngochieu]

I have been using this library in production for over a year, but recently, our server has been crashing and restarting several times a day when generating reports. This issue may be related to an increase in the number of users.

How can I resolve this problem? I am using .NET 6 and library version v1.5.86. My current implementation is as follows:

       services.AddSingleton(typeof(IConverter), new SynchronizedConverter(new PdfTools()));

    protected async Task<ExportResult> ConvertAsync(string folderPath, string fileName, string htmlContent, 
        bool isLandscape = false)
    {
        var saveFile = $"{folderPath}\\{fileName}.pdf";
        var doc = new HtmlToPdfDocument()
        {
            GlobalSettings = {
                    ColorMode = ColorMode.Color,
                    Orientation = isLandscape ? Orientation.Landscape: Orientation.Portrait,
                    PaperSize = PaperKind.A4,
                    Margins = new MarginSettings() { Top = 2, Bottom = 10, Left = 2, Right = 2 },
                    Outline = false,
                    Out = saveFile
                },
            Objects = {
                    new ObjectSettings() {
                        PagesCount = true,
                        HtmlContent = htmlContent,
                        WebSettings = { DefaultEncoding = "utf-8" },
                    }
                },
        };
        _converter.Convert(doc);
    }

[HakanL]

I haven't seen this error before, and your code looks correct. I wonder if there could be some special scenario on Linux where the GC is removing the callbacks, but obviously it's just speculation and hard to figure out. I've checked the code in the converter and I can't see anything obvious, plus a lot of people are using this, so it's odd that nothing has surfaced so far. Perhaps try an upgrade to .NET7 or 8?

[ninhngochieu]

@HakanL I'll give it a try, thank you so much for your support

[Kobi-TR]

@ninhngochieu Was there any update on this seeing something similar on our end and we're on .net8 plus we tried enabling GarbageCollectionAdaptationMode

[ninhngochieu]

@ninhngochieu Was there any update on this seeing something similar on our end and we're on .net8 plus we tried enabling GarbageCollectionAdaptationMode

I switched to Gotenberg, which fixed the issue. You should deploy this service—2 CPU cores and 2 GB of RAM should be sufficient. Large data exports may fail because rendering can be slow and cause timeouts. You can try it here: https://gotenberg.dev/docs/getting-started/installation