Atamai.Slice

Proof-of-concept solution for slicing minimal-api and using source generator to resolve the slices without runtime reflection or manual registrations.

We use Static abstract members in interfaces so .NET6 and <EnablePreviewFeatures>True</EnablePreviewFeatures> in csproj is required.

Example slice:

namespace Atamai.Slice.Sample.Slices.Session;

public class Create : IApiSlice
{
    public record CreateSession(string Username, string Password);

    public static void Register(IEndpointRouteBuilder builder) => builder
        .MapPost("/session", (CreateSession request, DataBase dataBase) =>
        {
            if (dataBase.Users.TryGetValue(request.Username, out var hashedPassword) &&
                PasswordHasher.Compare(hashedPassword, request.Password))
            {
                var token = Guid.NewGuid().ToString("N");
                dataBase.TokenUser[token] = request.Username;

                return Results.Ok(token);
            }

            return Results.Unauthorized();
        })
        .Produces<string>(StatusCodes.Status200OK)
        .Produces(StatusCodes.Status401Unauthorized);
}

Atamai.Slice.Generator will find all implementations of IApiSlice and generate something like the following:

public static class GeneratedApiSliceRegistrations 
{ 
    [System.Runtime.CompilerServices.ModuleInitializer]
    public static void Init() => Atamai.Slice.Extensions.OnLoad += OnLoad;

    private static void OnLoad(IEndpointRouteBuilder builder)
    {
        Atamai.Slice.Sample.Slices.Root.Register(builder);
        Atamai.Slice.Sample.Slices.Session.Create.Register(builder);
        Atamai.Slice.Sample.Slices.Session.Delete.Register(builder);
        Atamai.Slice.Sample.Slices.Session.Get.Register(builder);
        Atamai.Slice.Extensions.OnLoad -= OnLoad;
    }
}

app.UseSlice(); will trigger the OnLoad event and register all slices

Take a look at Atamai.Slice.Sample to see it in action.

Notes / Thoughts

• What if we have slices and a generated registration in an assembly that isn't the main startup assembly?
  • Adding something like a "dummy" method App.AddSlice().AddAssemblyFromType<Type> that just touches the type should work since it will invoke the ModuleInitializer on the GeneratedApiSliceRegistrations from that assembly.