ln.templates/ln.templates.service/render/PuppeteerRenderer.cs

using System;
using System.IO;
using Jint.Native.Object;
using ln.patterns;
using PuppeteerSharp;

namespace ln.templates.service.render
{
    public static class PuppeteerRenderer
    {
        private static BrowserFetcher _browserFetcher;

        public static Optional<Stream> RenderTemplate(Template template, string resourcePath, ObjectInstance globals)
        {
            using (StringWriter htmlWriter = new StringWriter())
            {
                try
                {
                    Context context = new Context(template.Resolver, htmlWriter);
                    template.Render(context, globals);

                    using (var browser = Puppeteer.LaunchAsync(new LaunchOptions
                           {
                               Headless = true,
                           }).Result)
                    {
                        using (var page = browser.NewPageAsync().Result)
                        {
                            page.GoToAsync(resourcePath).Wait();
                            page.SetContentAsync(htmlWriter.ToString(), new NavigationOptions()
                            {
                            }).Wait();

                            var footerTemplate = page.EvaluateFunctionAsync<string>($@"()=>{{
let footers = document.getElementsByTagName('footer');
if (footers.length){{
    let footerHtml = footers[0].outerHTML;
    footers[0].remove();
    return footerHtml;
}}
return null;
                }}").Result;

                            page.SetContentAsync(page.GetContentAsync().Result).Wait();

                            TempFileStream pdfTempStream = new TempFileStream(".pdf");
                            page.PdfAsync(pdfTempStream.Name, new PdfOptions()
                            {
                                HeaderTemplate = "<div></div>",
                                FooterTemplate = footerTemplate,
                                DisplayHeaderFooter = true,
                            }).Wait();

                            return pdfTempStream;
                        }
                    }
                }
                catch (Exception e)
                {
                    return e;
                }
            }
        }

        static PuppeteerRenderer()
        {
            _browserFetcher = new BrowserFetcher();
            _browserFetcher.DownloadAsync(BrowserFetcher.DefaultChromiumRevision).Wait();
        }

    }
}