REslava.Result.SourceGenerators 1.35.0

REslava.Result.SourceGenerators

Zero-boilerplate ASP.NET endpoint generation — write business logic, Minimal API + MVC endpoints generate themselves.

What It Does

This package contains 13 Roslyn source generators that eliminate ASP.NET boilerplate:

Minimal API

• SmartEndpoints — auto-generates complete endpoint registration from your service classes; includes CancellationToken threading, auto-validation, filters, caching, and rate limiting
• ResultToIResult — converts Result<T> to IResult with domain error-aware HTTP status codes
• OneOfToIResult — converts OneOf<T1,...,T6> to IResult with tag-based + heuristic error mapping (arities 2–6)

MVC Controllers

• ResultToActionResult — converts Result<T> to IActionResult with convention-based HTTP mapping
• OneOfToActionResult — converts OneOf<T1,...,T6> to IActionResult with domain error auto-mapping (arities 2–6)

Cross-cutting

• OpenAPI metadata — auto-generates .Produces<T>(), .WithSummary(), .WithTags() with accurate error status codes
• Authorization — generates .RequireAuthorization(), .AllowAnonymous() from attributes
• [Validate] — generates .Validate() extension methods from DataAnnotations; auto-injected by SmartEndpoints
• [FluentValidate] — (from REslava.Result.FluentValidation) SmartEndpoints detects [FluentValidate] on body params and auto-injects IValidator<T> as a lambda parameter

Before / After

// Before: Manual endpoint registration (30+ lines per controller)
app.MapGet("/api/products", async (IProductService svc) => {
    var result = await svc.GetProducts();
    return result.Match(
        products => Results.Ok(products),
        errors => Results.BadRequest(errors));
}).WithName("GetProducts").WithTags("Products").Produces<List<Product>>(200).Produces(400);

app.MapGet("/api/products/{id}", async (int id, IProductService svc) => { /* ... */ });
app.MapPost("/api/products", async (CreateProductRequest req, IProductService svc) => { /* ... */ });
// ... repeat for every endpoint

// After: SmartEndpoints (just your business logic)
[AutoGenerateEndpoints(RoutePrefix = "/api/products")]
public class ProductService(AppDbContext db)
{
    public async Task<Result<List<Product>>> GetProducts()
        => Result.Ok(await db.Products.ToListAsync());

    public async Task<Result<Product>> GetProductById(int id)
        => await db.Products.FindAsync(id) is { } p
            ? Result.Ok(p)
            : Result.Fail<Product>("Not found");

    public async Task<Result<Product>> CreateProduct(CreateProductRequest request)
        => Result.Ok(db.Products.Add(new Product(request)).Entity);
}

// In Program.cs — one line:
app.MapProductServiceEndpoints();

Quick Start

dotnet add package REslava.Result
dotnet add package REslava.Result.SourceGenerators

using REslava.Result;

[AutoGenerateEndpoints(RoutePrefix = "/api/users")]
public class UserService(UserRepository repo)
{
    public async Task<Result<User>> GetUserById(int id)
        => await repo.FindAsync(id) is { } user
            ? user    // implicit conversion to Result<User>
            : new NotFoundError($"User {id} not found");
}

// Program.cs
app.MapUserServiceEndpoints();  // auto-generated extension method

The generator infers:

• HTTP method from name: Get* → GET, Create*/Add* → POST, Update* → PUT, Delete* → DELETE
• Routes with {id} parameters when methods have an id parameter
• DI via ASP.NET parameter binding (services injected as lambda parameters)
• CancellationToken — automatically threaded through when service method declares CancellationToken cancellationToken = default
• Validation — auto-injects .Validate() when request type carries [Validate]

Requires

• REslava.Result (core library)

Links

• GitHub Repository — Full documentation, architecture guide
• Minimal API Demo
• MVC Demo
• Changelog

MIT License | .NET 8 / 9 / 10