src/PdfEncoder.Infrastructure/Pdf/PdfInputValidator.cs - master - afanasevn/PdfEncoder

src/PdfEncoder.Infrastructure/Pdf/PdfInputValidator.cs
92 строки3 KB
IBS\NAfanasev
DocumentContext local functional
01 июл 2026, 15:30
01 июл 2026, 15:30b4038c9
using Microsoft.Extensions.Options;
using PdfEncoder.Application.Abstractions;
using PdfEncoder.Application.Options;
using PdfEncoder.Domain.Errors;
using UglyToad.PdfPig;

namespace PdfEncoder.Infrastructure.Pdf;

/// <summary>
/// Валидация входного PDF перед pipeline.
/// </summary>
public sealed class PdfInputValidator(IOptions<UploadOptions> uploadOptions) : IPdfInputValidator
{
    private static ReadOnlySpan<byte> PdfMagic => "%PDF"u8;

    /// <inheritdoc />
    public Task<int> ValidateAsync(
        ReadOnlyMemory<byte> content,
        string fileName,
        CancellationToken ct)
    {
        ct.ThrowIfCancellationRequested();

        if (content.IsEmpty)
        {
            throw new PdfValidationException(
                "invalid-file",
                "File is empty.",
                statusCode: 400);
        }

        var span = content.Span;
        if (span.Length < PdfMagic.Length || !span[..PdfMagic.Length].SequenceEqual(PdfMagic))
        {
            throw new PdfValidationException(
                "invalid-file",
                "File is not a valid PDF or is empty.",
                statusCode: 400);
        }

        var options = uploadOptions.Value;
        if (span.Length > options.MaxFileSizeBytes)
        {
            throw new PdfValidationException(
                "file-too-large",
                $"File exceeds maximum size of {options.MaxFileSizeBytes} bytes.",
                statusCode: 413);
        }

        try
        {
            using var document = PdfDocument.Open(content);
            if (document.IsEncrypted)
            {
                throw new PdfValidationException(
                    "encrypted-pdf-not-supported",
                    "Encrypted PDF is not supported.",
                    statusCode: 400);
            }

            var pageCount = document.NumberOfPages;
            if (pageCount <= 0)
            {
                throw new PdfValidationException(
                    "invalid-file",
                    "PDF contains no pages.",
                    statusCode: 400);
            }

            if (pageCount > options.MaxPages)
            {
                throw new PdfValidationException(
                    "too-many-pages",
                    $"PDF exceeds maximum page count of {options.MaxPages}.",
                    statusCode: 400);
            }

            return Task.FromResult(pageCount);
        }
        catch (PdfValidationException)
        {
            throw;
        }
        catch (Exception ex)
        {
            throw new PdfValidationException(
                "invalid-file",
                $"Failed to read PDF '{fileName}': {ex.Message}",
                statusCode: 400);
        }
    }
}