ln.templates/ln.templates.service/render/HtmlToPDF.cs

using System;
using System.Diagnostics;
using System.IO;
using System.Text;

namespace ln.templates.service.render
{

    public class HtmlToPDF
    {
        public static string WkExecutablePath { get; set; }
        public static string ChromiumExecutablePath { get; set; }

        public static bool RenderPDF(Stream htmlStream, string resourcePath, out Stream pdfStream)
        {
            if (htmlStream is TempFileStream tempFileStream)
            {
                return RenderPDF(tempFileStream.Name, resourcePath, out pdfStream);
            }
            else
            {
                using (TempFileStream htmlTempStream = new TempFileStream(".html"))
                {
                    htmlStream.CopyTo(htmlTempStream);
                    return RenderPDF(htmlTempStream.Name, resourcePath, out pdfStream);
                }
            }
        }

        public static bool RenderPDF(string htmlFileName, string resourcePath, out Stream pdfStream)
        {
            if (ChromiumExecutablePath is string)
                return RenderPDFChromium(htmlFileName, resourcePath, out pdfStream);
            else
                return RenderPDFWk(htmlFileName, resourcePath, out pdfStream);
        }
        
        public static bool RenderPDFWk(string htmlFileName, string resourcePath, out Stream pdfStream)
        {
            if (!File.Exists(htmlFileName))
                throw new FileNotFoundException(htmlFileName);
            if ((resourcePath is String) && !Directory.Exists(resourcePath))
                throw new DirectoryNotFoundException(resourcePath);

            var pdfTempStream = new TempFileStream(".pdf");

            StringBuilder argumentsBuilder = new StringBuilder();
            if (resourcePath is String)
                argumentsBuilder.AppendFormat("--allow {0} ", resourcePath);
            argumentsBuilder.Append("--disable-javascript --enable-local-file-access -B 0 -L 0 -R 0 -T 0 --print-media-type");

            argumentsBuilder.AppendFormat(" {0}", htmlFileName);
            argumentsBuilder.AppendFormat(" {0}", pdfTempStream.Name);

            Console.WriteLine("Starting WkHtmlToPdf: {0} {1}", WkExecutablePath, argumentsBuilder.ToString());
            var p = Process.Start(WkExecutablePath, argumentsBuilder.ToString());
            p.WaitForExit();
            if (p.ExitCode != 0)
            {
                pdfTempStream.Dispose();
                pdfStream = null;
                return false;
            }

            pdfStream = pdfTempStream;
            return true;
        }

        public static bool RenderPDFChromium(string htmlFileName, string resourcePath, out Stream pdfStream)
        {
            var pdfTempStream = new TempFileStream(".pdf");
            
            string command =
                String.Format(
                    "--headless=old --disable-gpu --print-to-pdf={1} --no-pdf-header-footer --no-margins {0}",
                    htmlFileName,
                    pdfTempStream.Name
                );
            
            Console.WriteLine("Starting chromium: {0} {1}", ChromiumExecutablePath, command);
            var p = Process.Start(ChromiumExecutablePath, command);
            p.WaitForExit();
            if (p.ExitCode != 0)
            {
                pdfTempStream.Dispose();
                pdfStream = null;
                return false;
            }
            
            pdfStream = pdfTempStream;
            return true;
        }

        static string LookupExecutable(String[] searchPaths)
        {
            foreach (var tryExe in searchPaths)
            {
                if (File.Exists(tryExe))
                    return tryExe;
            }

            return null;
        }
        
        static HtmlToPDF()
        {
            WkExecutablePath = LookupExecutable(new String[]
            {
                "/usr/bin/wkhtmltopdf",
                "/usr/local/bin/wkhtmltopdf",
            });
            ChromiumExecutablePath = LookupExecutable(new String[]
            {
                "/usr/bin/chromium",
                "/usr/local/bin/chromium",
                "/usr/bin/chrome",
                "/usr/local/bin/chrome",
            });
        }
    }

}