ASP.NET Core In Memory File Download

DownloadEndpoint.cs

internal static class DownloadEndpoint
{
    public static void MapDownloadEndpoints(this IEndpointRouteBuilder builder)
    {
        builder
            .MapGet("/api/download/{containerId}", DownloadContainer);
    }

    private static async Task DownloadContainer(
        HttpContext context,
        Guid containerId)
    {
        context.Response.ContentType = "application/octet-stream";
        context.Response.Headers.Append("Content-Disposition", $"attachment; filename=\"Container-{containerId}.zip\"");

        var folderPath = @$"D:\{containerId}";
        var files = Directory.GetFiles(folderPath);

        var bodyStream = context.Response.BodyWriter.AsStream();
        using var archive = new ZipArchive(bodyStream, ZipArchiveMode.Create);

        foreach (var file in files)
        {
            var entry = archive.CreateEntry(Path.GetFileName(file), CompressionLevel.NoCompression);
            var entryStream = entry.Open();
            var fileStream = File.OpenRead(file);
            await fileStream.CopyToAsync(entryStream);

            entryStream.Close();
        }
    }
}