Como executar Aspose.PDF for .NET 8 no Docker

Pré-requisitos

Os seguintes exemplos foram testados com:

• Docker v.25.0.2 e Docker Desktop 4.27.1.
• Visual Studio 2022 Community Edition v.17.0.5.
• .NET 8 SDK é usado no exemplo fornecido abaixo.
• Aspose.PDF.Drawing v.24.01.

Criar aplicação de exemplo para Contêiner Docker Linux

1. Inicie o Visual Studio 2022 e escolha o template ASP.NET Core Web App (Model-View-Controller) e pressione Next.
2. Na janela Configure seu novo projeto, defina o nome e a localização desejados do projeto e pressione Next.
3. Na janela Informações adicionais, escolha .NET 6.0 (Suporte a longo prazo) e habilite o suporte a Docker. Você também pode definir o Docker OS como Linux, se necessário.
4. Pressione Create.
5. Escolha Tools->Nuget Package Manager->Package Manager Console e instale Aspose.PDF for .NET (use o comando Install-Package Aspose.PDF).

Gerar documento PDF usando ASP.NET Core Web App em contêiner Linux

Usaremos o código do Exemplo Complexo neste aplicativo. Por favor, siga este link para uma explicação mais detalhada.

1. Crie a pasta images na pasta wwwroot e coloque a imagem logo.png. Você pode baixar esta imagem aqui.
2. Crie a pasta fonts na pasta wwwroot e coloque as fontes Roboto lá.
3. Crie a pasta samples na pasta wwwroot e coloque os dados de exemplo lá.
4. Substitua o código em HomeController.cs pelo seguinte trecho (observe que você pode ter outro namespace):

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. Substitua o conteúdo em Dockerfile pelo seguinte conteúdo:

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"]