ASP.NET Core

Haitch.Unions.AspNetCore maps Result<T> to minimal API results, and Error to HTTP status codes and ProblemDetails.

Installation

dotnet add package Haitch.Unions.AspNetCore

ToHttpResult / ToHttpResultAsync

Result<T>.ToHttpResult() returns 200 OK with the value when Ok, otherwise the error’s ProblemDetails. Result<Unit>.ToHttpResult() returns 204 No Content instead of 200 OK on Ok. Both have Task<...> async forms, ToHttpResultAsync().

app.MapGet("/orders/{id:int}", (int id, IOrderRepository repository) =>
    GetOrder(repository, id).ToHttpResult());

app.MapDelete("/orders/{id:int}", (int id, IOrderRepository repository) =>
    DeleteOrder(repository, id).ToHttpResult());

app.MapGet("/orders/{id:int}/async", (int id, IOrderRepository repository) =>
    GetOrderAsync(repository, id).ToHttpResultAsync());

ToStatusCode

Maps an Error to an HTTP status code by its kind, unless the error implements IHttpError — then its StatusCode wins.

Error kind	Status code
NotFoundError	404 Not Found
ValidationError	400 Bad Request
ConflictError	409 Conflict
UnauthorizedError	401 Unauthorized
ForbiddenError	403 Forbidden
UnexpectedError	500 Internal Server Error
A plain Error, or any other kind	400 Bad Request

ToProblemDetails

Builds a ProblemDetails — or an HttpValidationProblemDetails populated from Failures, for a ValidationError — with Status from ToStatusCode(), Detail from Description, and the error’s Code added to Extensions["code"].

IHttpError

Implement IHttpError on a custom error kind to choose its own status code instead of relying on the kind-based mapping:

public record RateLimitedError(string Code, string Description) : Error(Code, Description), IHttpError
{
    public int StatusCode => StatusCodes.Status429TooManyRequests;
}