Cómo ejecutar Aspose.PDF for .NET 8 en Docker

Requisitos previos

Los siguientes ejemplos se probaron con:

• Docker v.25.0.2 y Docker Desktop 4.27.1.
• Visual Studio 2022 Community Edition v.17.0.5.
• Se utiliza el SDK de .NET 8 en el ejemplo proporcionado a continuación.
• Aspose.PDF.Drawing v.24.01.

Crear una aplicación de muestra para el contenedor Docker Linux

1. Inicia Visual Studio 2022 y elige la plantilla ASP.NET Core Web App (Modelo-Vista-Controlador) y presiona Siguiente.
2. En la ventana Configura tu nuevo proyecto, establece el nombre y la ubicación del proyecto deseados y presiona Siguiente.
3. En la ventana Información adicional, elige .NET 6.0 (Soporte a largo plazo) y habilita el soporte de Docker. También puedes establecer Docker OS en Linux si es necesario.
4. Presiona Crear.
5. Elige Herramientas->Administrador de paquetes Nuget->Consola del administrador de paquetes e instala Aspose.PDF for .NET (usa el comando Install-Package Aspose.PDF).

Generar documento PDF usando ASP.NET Core Web App en contenedor Linux

Usaremos el código del Ejemplo Complejo en esta aplicación. Por favor, sigue este enlace para una explicación más detallada.

1. Crea una carpeta images en la carpeta wwwroot y coloca la imagen logo.png. Puedes descargar esta imagen aquí.
2. Crea una carpeta fonts en la carpeta wwwroot y coloca las fuentes Roboto allí.
3. Crea una carpeta samples en la carpeta wwwroot y coloca los datos de muestra allí.
4. Reemplaza el código en HomeController.cs con el siguiente fragmento (ten en cuenta que puedes tener otro espacio de nombres):

using Aspose.Pdf;
using Aspose.Pdf.Devices;
using Aspose.Pdf.Text;
using Docker.LinuxDemo.Models;
using Microsoft.AspNetCore.Mvc;
using System.Diagnostics;

namespace Docker.LinuxDemo.Controllers
{
    // <summary>
    // Represents a controller for the home page and PDF generation in a Linux demo application.
    // </summary>
    public class HomeController(ILogger<HomeController> logger, IWebHostEnvironment appEnvironment) : Controller
    {
        private readonly ILogger<HomeController> _logger = logger;
        private readonly IWebHostEnvironment _appEnvironment = appEnvironment;

        // <summary>
        // Displays the index view.
        // </summary>
        public IActionResult Index()
        {
            return View();
        }

        // <summary>
        // Generates a PDF document and returns it as a file.
        // </summary>
        public IActionResult Generate()
        {
            const string fileType = "application/pdf";
            const string fileName = "sample.pdf";
            FontRepository.Sources.Add(new FolderFontSource(Path.Combine(_appEnvironment.WebRootPath, "fonts")));
            var memoryStream = new MemoryStream();

            _logger.LogInformation("PDF Generation: Start ");
            // Create PDF document
            using (var document = new Aspose.Pdf.Document())
            {
                // Add page
                var page = document.Pages.Add();

                // Add image
                var imageFileName = Path.Combine(_appEnvironment.WebRootPath, "images", "logo.png");
                page.AddImage(imageFileName, new Rectangle(20, 730, 120, 830));

                // Add Header
                var header = new TextFragment("New ferry routes in Fall 2020");
                header.TextState.Font = FontRepository.FindFont("Roboto");
                header.TextState.FontSize = 24;
                header.HorizontalAlignment = HorizontalAlignment.Center;
                header.Position = new Position(130, 720);
                page.Paragraphs.Add(header);

                // Add description
                var descriptionText = "Visitors must buy tickets online and tickets are limited to 5,000 per day. Ferry service is operating at half capacity and on a reduced schedule. Expect lineups.";
                var description = new TextFragment(descriptionText);
                description.TextState.Font = FontRepository.FindFont("Helvetica");
                description.TextState.FontSize = 14;
                description.HorizontalAlignment = HorizontalAlignment.Left;
                page.Paragraphs.Add(description);

                // Add table
                var table = new Table
                {
                    ColumnWidths = "200",
                    Border = new BorderInfo(BorderSide.Box, 1f, Color.Black),
                    DefaultCellBorder = new BorderInfo(BorderSide.Box, 0.5f, Color.Gray),
                    DefaultCellPadding = new MarginInfo(4.5, 4.5, 4.5, 4.5),
                    Margin =
                    {
                        Top = 10,
                        Bottom = 10
                    },
                    DefaultCellTextState =
                    {
                        Font =  FontRepository.FindFont("Helvetica")
                    }
                };

                var headerRow = table.Rows.Add();
                headerRow.Cells.Add("Departs City");
                headerRow.Cells.Add("Departs Island");
                foreach (Cell headerRowCell in headerRow.Cells)
                {
                    headerRowCell.BackgroundColor = Color.LightGray;
                    headerRowCell.DefaultCellTextState.ForegroundColor = Color.FromRgb(0.1, 0.1, 0.1);
                }

                var time = new TimeSpan(6, 0, 0);
                var incTime = new TimeSpan(0, 30, 0);
                for (int i = 0; i < 10; i++)
                {
                    var dataRow = table.Rows.Add();
                    dataRow.Cells.Add(time.ToString(@"hh\:mm"));
                    time = time.Add(incTime);
                    dataRow.Cells.Add(time.ToString(@"hh\:mm"));
                }

                page.Paragraphs.Add(table);

                document.Save(memoryStream);
            }
            _logger.LogInformation("PDF Generation: Finish");
            return File(memoryStream, fileType, fileName);
        }

        // <summary>
        // Converts a file to a different format based on the provided id.
        // </summary>
        public FileStreamResult Convert(string id)
        {
            return id switch
            {
                "xps-to-pdf" => ConvertXpsToPdf(),
                "pdf-to-jpeg" => ConvertPdfToJpeg(),
                _ => throw new NotImplementedException(),
            };
        }

        // <summary>
        // Converts a PDF file to JPEG format and returns it as a file.
        // </summary>
        private FileStreamResult ConvertPdfToJpeg()
        {
            const string fileType = "image/jpeg";
            const string fileName = "sample.jpeg";

            var memoryStream = new MemoryStream();
            var pdfFileName = Path.Combine(_appEnvironment.WebRootPath, "samples", "samples-new.pdf");

            // Open PDF document
            using (var document = new Aspose.Pdf.Document(pdfFileName))
            {
                var resolution = new Resolution(300);
                var renderer = new JpegDevice(resolution, 90);
                renderer.Process(document.Pages[1], memoryStream);
                memoryStream.Seek(0, SeekOrigin.Begin);
                return File(memoryStream, fileType, fileName);
            }
        }

        // <summary>
        // Converts an XPS file to PDF format and returns it as a file.
        // </summary>
        private FileStreamResult ConvertXpsToPdf()
        {
            const string fileType = "application/pdf";
            const string fileName = "sample.pdf";

            var memoryStream = new MemoryStream();
            var xpsFileName = Path.Combine(_appEnvironment.WebRootPath, "samples", "samples-new.oxps");

            // Open XPS document
            using (var document = new Aspose.Pdf.Document(xpsFileName, new Aspose.Pdf.XpsLoadOptions()))
            {
                document.Save(memoryStream);
            }

            return File(memoryStream, fileType, fileName);
        }

        // <summary>
        // Displays the privacy view.
        // </summary>
        public IActionResult Privacy()
        {
            return View();
        }

        // <summary>
        // Displays the error view.
        // </summary>
        [ResponseCache(Duration = 0, Location = ResponseCacheLocation.None, NoStore = true)]
        public IActionResult Error()
        {
            return View(new ErrorViewModel { RequestId = Activity.Current?.Id ?? HttpContext.TraceIdentifier });
        }
    }
}

1. Reemplaza el contenido en Dockerfile con el siguiente contenido:

FROM mcr.microsoft.com/dotnet/aspnet:8.0 AS base

RUN apt-get update && apt-get install -y libgdiplus
RUN apt install software-properties-common -y
RUN echo "deb http://deb.debian.org/debian bookworm contrib non-free" > /etc/apt/sources.list.d/contrib.list
RUN apt update && apt upgrade
RUN apt install ttf-mscorefonts-installer -y


USER app
WORKDIR /app
EXPOSE 8080
EXPOSE 8081

FROM mcr.microsoft.com/dotnet/sdk:8.0 AS build
ARG BUILD_CONFIGURATION=Release
WORKDIR /src
COPY ["Docker.Demo/Docker.LinuxDemo.csproj", "Docker.Demo/"]
RUN dotnet restore "./Docker.Demo/./Docker.LinuxDemo.csproj"
COPY . .
WORKDIR "/src/Docker.Demo"
RUN dotnet build "./Docker.LinuxDemo.csproj" -c $BUILD_CONFIGURATION -o /app/build

FROM build AS publish
ARG BUILD_CONFIGURATION=Release
RUN dotnet publish "./Docker.LinuxDemo.csproj" -c $BUILD_CONFIGURATION -o /app/publish /p:UseAppHost=false

FROM base AS final
WORKDIR /app
COPY --from=publish /app/publish .
ENTRYPOINT ["dotnet", "Docker.LinuxDemo.dll"]