Files
ersatztv/ErsatzTV.Application/Artworks/Commands/UploadArtworkHandler.cs
T

82 lines
3.4 KiB
C#

using ErsatzTV.Core;
using ErsatzTV.Core.Api.Artwork;
using ErsatzTV.Core.Domain;
using ErsatzTV.Core.Images;
using ErsatzTV.Core.Interfaces.Images;
namespace ErsatzTV.Application.Artworks;
public class UploadArtworkHandler : IRequestHandler<UploadArtwork, Either<BaseError, ArtworkUploadResponseModel>>
{
private readonly IImageCache _imageCache;
private readonly IRemoteImageValidator _validator;
public UploadArtworkHandler(IImageCache imageCache, IRemoteImageValidator validator)
{
_imageCache = imageCache;
_validator = validator;
}
public async Task<Either<BaseError, ArtworkUploadResponseModel>> Handle(
UploadArtwork request,
CancellationToken cancellationToken)
{
// Buffer the upload so we can sniff its true format before storing it. The request body is
// already bounded by the Kestrel MaxRequestBodySize / the controller's size check, so this
// is a bounded read.
byte[] bytes;
await using (var buffer = new MemoryStream())
{
await request.Stream.CopyToAsync(buffer, cancellationToken);
bytes = buffer.ToArray();
}
// Derive the content type from the actual bytes, never from the client-declared value
// (issue #283 — a spoofed image/png header let a <script> payload be stored and later served
// as HTML). A payload that isn't a supported raster image is rejected here.
Option<string> maybeContentType = ImageContentTypes.DetectContentType(bytes);
if (maybeContentType.IsNone)
{
return BaseError.New(
$"Uploaded file is not a supported image; supported types are: {string.Join(", ", ImageContentTypes.Accepted)}");
}
string contentType = maybeContentType.IfNone(string.Empty);
// One rule: anything entering the logo cache is decode-budget-checked. A supported format is
// not enough — a small header can declare a multi-gigabyte canvas (a decompression bomb), so
// reject it here before it lands in the cache. The synthetic upload:// Uri is only for the
// exception message text. (ersatztv#525)
using (var probe = new MemoryStream(bytes, writable: false))
{
try
{
await _validator.Validate(probe, new Uri("upload://artwork"), cancellationToken);
}
catch (Exception ex)
{
return BaseError.New($"Image cannot be used: {ex.Message}");
}
}
using var toCache = new MemoryStream(bytes, writable: false);
Either<BaseError, string> maybeFileName = await _imageCache.SaveArtworkToCache(
toCache,
request.ArtworkKind);
return maybeFileName.Map(fileName => new ArtworkUploadResponseModel(
BuildPath(request.ArtworkKind, fileName),
contentType));
}
// Mirror the on-disk conventions the Blazor editors use so the returned path is a drop-in
// for ArtworkContentTypeModel.Path: channel logos are addressed as "iptv/logos/{file}"
// (see ChannelEditor.UploadLogo), watermarks by the bare cache file name (see WatermarkEditor).
private static string BuildPath(ArtworkKind artworkKind, string fileName) =>
artworkKind switch
{
ArtworkKind.Logo => $"iptv/logos/{fileName}",
_ => fileName
};
}