Converting Documents with Microsoft Azure App service

This article provides detailed step-by-step instructions for converting PDF documents in Microsoft Azure using Aspose.PDF for .NET and Azure App service.

Prerequisites

  • Visual Studio 2022 Community Edition with installed Azure development or Visual Studio Code.
  • Azure Account: You need an Azure subscription, create a free account before beginning.
  • .NET 6 SDK.
  • Aspose.PDF for .NET.

Create Azure Resources

Create App Service

  1. Go to Azure Portal (https://portal.azure.com).
  2. Create a new Resource Group.
  3. Create a new App Service:
    • Choose .NET 6 (LTS) runtime.
    • Select appropriate pricing tier.
  4. Create an Application Insights resource for logging.

Create Project

Create Visual Studio Project

  1. Open Visual Studio 2022.
  2. Click “Create a new project”.
  3. Select “ASP.NET Core Web API”.
  4. Name your project “PdfConversionService”.
  5. Select “.NET 6.0” or later.
  6. Click “Create”.

Create Visual Studio Code Project

Install Prerequisites

  1. Visual Code extensions:
code --install-extension ms-dotnettools.csharp
code --install-extension ms-azuretools.vscode-azureappservice
  1. Install Azure CLI:
  • Windows: Download from Microsoft’s website.
  • macOS: brew install azure-cli.
  • Linux: curl -sL https://aka.ms/InstallAzureCLIDeb | sudo bash.

Configure Project

  1. Open project in Visual Studio Code:
code .
  1. Add NuGet packages by creating/updating PdfConverterApp.csproj:
<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>net6.0</TargetFramework>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="Aspose.PDF" Version="24.10.0" />
    <PackageReference Include="Microsoft.ApplicationInsights.AspNetCore" Version="2.22.0" />
    <PackageReference Include="Microsoft.Extensions.Logging.AzureAppServices" Version="8.0.10" />
  </ItemGroup>
</Project>
  1. Add configuration:
// .vscode/launch.json
{
    "version": "0.2.0",
    "configurations": [
        {
            "name": ".NET Core Launch (web)",
            "type": "coreclr",
            "request": "launch",
            "preLaunchTask": "build",
            "program": "${workspaceFolder}/bin/Debug/net6.0/PdfConversionService.dll",
            "args": [],
            "cwd": "${workspaceFolder}",
            "stopAtEntry": false,
            "env": {
                "ASPNETCORE_ENVIRONMENT": "Development"
            }
        }
    ]
}
  1. Create project structure:
mkdir Controllers
touch Controllers/PdfController.cs

Install Required NuGet Packages

In Visual Studio open Package Manager Console and run:

Install-Package Aspose.PDF
Install-Package Microsoft.ApplicationInsights.AspNetCore
Install-Package Microsoft.Extensions.Logging.AzureAppServices

In Visual Studio Code run:

dotnet restore

Configure Aspose License

In Visual Studio:

  1. Copy your Aspose.PDF license file to the project.
  2. Right-click on the license file, and select “Properties”.
  3. Set “Copy to Output Directory” to “Copy always”.
  4. Add license initialization code in the Program.cs:
var license = new Aspose.Pdf.License();
license.SetLicense("Aspose.PDF.lic");

Create code

In Visual Studio:

  1. Right-click on Controllers folder.
  2. Add → New Item → API Controller - Empty.
  3. Name your file “PdfController.cs”.
// PdfController.cs
using Microsoft.AspNetCore.Mvc;

[ApiController]
[Route("api/[controller]")]
public class PdfController : ControllerBase
{
    private readonly ILogger<PdfController> _logger;

    public PdfController(ILogger<PdfController> logger)
    {
        _logger = logger;
    }

    [HttpPost("convert")]
    public async Task<IActionResult> ConvertPdf(
        IFormFile file,
        [FromQuery] string outputFormat = "docx")
    {
        try
        {
            if (file == null || file.Length == 0)
                return BadRequest("No file uploaded");

            // Validate input file is PDF
            if (!file.ContentType.Equals("application/pdf", StringComparison.OrdinalIgnoreCase))
                return BadRequest("File must be a PDF");

            using var inputStream = file.OpenReadStream();
            using var document = new Aspose.Pdf.Document(inputStream);
            using var outputStream = new MemoryStream();

            switch (outputFormat.ToLower())
            {
                case "docx":
                    document.Save(outputStream, Aspose.Pdf.SaveFormat.DocX);
                    return File(outputStream.ToArray(),
                        "application/vnd.openxmlformats-officedocument.wordprocessingml.document",
                        "converted.docx");

                case "html":
                    document.Save(outputStream, Aspose.Pdf.SaveFormat.Html);
                    return File(outputStream.ToArray(),
                        "text/html",
                        "converted.html");

                case "jpg":
                case "jpeg":
                    var jpegDevice = new Aspose.Pdf.Devices.JpegDevice();
                    jpegDevice.Process(document.Pages[1], outputStream);
                    return File(outputStream.ToArray(),
                        "image/jpeg",
                        "converted.jpg");

                case "png":
                    var pngDevice = new Aspose.Pdf.Devices.PngDevice();
                    pngDevice.Process(document.Pages[1], outputStream);
                    return File(outputStream.ToArray(),
                        "image/png",
                        "converted.png");

                default:
                    return BadRequest("Unsupported output format");
            }
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error converting PDF");
            return StatusCode(500, "Internal server error");
        }
    }
}

// Program.cs
var builder = WebApplication.CreateBuilder(args);

builder.Services.AddControllers();
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();

// Add logging
builder.Services.AddApplicationInsightsTelemetry();
builder.Services.AddLogging(logging =>
{
    logging.AddConsole();
    logging.AddDebug();
    logging.AddAzureWebAppDiagnostics();
});

var app = builder.Build();

// Initialize license
var license = new Aspose.Pdf.License();
license.SetLicense("Aspose.PDF.lic");

if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();
}

app.UseHttpsRedirection();
app.UseAuthorization();
app.MapControllers();
app.Run();

Configure application settings

  1. Open appsettings.json.
  2. Add configuration:
{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Warning"
    }
  },
  "AllowedHosts": "*",
  "ApplicationInsights": {
    "ConnectionString": "Your-Connection-String"
  }
}

Replace Your-Connection-StringG with your actual connection string from Azure Portal.

Test Locally

In Visual Studio:

  1. Press F5 to run the application.
  2. Swagger UI will open.
  3. Test the /api/pdf/convert endpoint:
    • Click “Try it out”.
    • Upload a PDF file.
    • Select output format.
    • Execute and verify the conversion.

In Visual Studio Code:

dotnet run

curl -X POST "https://localhost:5001/api/pdf/convert?outputFormat=docx" \
     -F "file=@sample.pdf" \
     -o converted.docx

Deploy to Azure

In Visual Studio:

  1. Right-click on the project.
  2. Select “Publish”.
  3. Choose “Azure” as target.
  4. Select “Azure App Service (Windows)”.
  5. Select your subscription and App Service.
  6. Click “Publish”.

In Visual Studio Code:

dotnet publish -c Release

az webapp deployment source config-zip \
    --resource-group $resourceGroup \
    --name $appName \
    --src bin/Release/net6.0/publish.zip

az webapp deploy \
    --resource-group $resourceGroup \
    --name $appName \
    --src-path "Aspose.PDF.lic" \
    --target-path "site/wwwroot/Aspose.PDF.lic"

Configure Azure App Service

  1. Go to Azure Portal.
  2. Open your App Service.
  3. Configure settings: 
    App Settings:
- WEBSITE_RUN_FROM_PACKAGE=1
- ASPNETCORE_ENVIRONMENT=Production

Test the Deployed Service

Use Postman or curl to test:

curl -X POST "https://your-app.azurewebsites.net/api/pdf/convert?outputFormat=docx" \
     -F "file=@sample.pdf" \
     -o converted.docx

Supported Formats

The list of supported formats can be found here.

Trobleshooting

Important Configuration Options

  1. File Size Limits Add to web.config:
<configuration>
  <system.webServer>
    <security>
      <requestFiltering>
        <requestLimits maxAllowedContentLength="104857600" />
      </requestFiltering>
    </security>
  </system.webServer>
</configuration>
  1. CORS (if needed) In Program.cs:
builder.Services.AddCors(options =>
{
    options.AddPolicy("AllowSpecificOrigin",
        builder => builder
            .WithOrigins("https://your-frontend-domain.com")
            .AllowAnyMethod()
            .AllowAnyHeader());
});
  1. Authentication (if needed)
builder.Services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
    .AddJwtBearer(options => {
        // Configure JWT options
    });
Converting Documents with Microsoft Azure function