Options and dependency injection

Shell 
dotnet add package Nullean.Entities.Extensions.DependencyInjection

Nullean.Entities.Extensions.DependencyInjection registers your ConstraintSet<T> values in the service collection, adds an IConstraintRegistry that validates an object it only holds as object, and plugs constraints into IOptions<T> validation. It depends on Nullean.Entities only, uses no reflection, and is trim and NativeAOT clean. The ASP.NET Core and Argh packages turn these registrations into HTTP and command-line behaviour.

C# 
services.AddOptions<ServerOptions>().BindConfiguration("Server").ValidateConstraints(ServerRules.All).ValidateOnStart();

A violation fails startup with OptionsValidationException, with failures worded Member: message:

Text 
Microsoft.Extensions.Options.OptionsValidationException: Port: must be between 1 and 65535

ValidateConstraints() with no argument takes T.Constraints for a type that declares its own. Only errors fail the options; warnings and hints do not. A named options builder validates only its own name.

  • services.AddConstraints<T>() registers T.Constraints, for a T : IHaveConstraints<T> (a partial type with [Constraint] fields).
  • services.AddConstraints(OrderRules.All) registers a companion's set, for types you cannot make partial.
  • services.AddConstraints<T, TFor>(companion) registers a generated companion and makes it resolvable as IConstraintsFor<T>.

Every call lands in one ConstraintRegistry singleton. It uses the container's TimeProvider when one is registered, so time-based rules follow your clock.

C# 
var registry = provider.GetRequiredService<IConstraintRegistry>();

if (registry.TryValidate(body, out var violations) && violations.Count > 0)
{
	var errors = ViolationErrors.ToDictionary(violations);   // { "Email": ["must be an email address"] }
}

TryValidate returning false means nothing is registered for that type, not that the value is valid. It looks up the exact runtime type, so a derived type is not validated by its base's set. ViolationErrors.ToDictionary groups errors into ProblemDetails' errors shape and drops warnings and hints. A second AddConstraints for the same T replaces the first.