Validating user input

ALPHA

This has not yet been fully fleshed out. For now, the general idea is that user-facing validation is a separate layer from the declarative expectations about what inputs your Action takes (e.g. expects :params and pass to a form object, rather than accepting field-level params directly).

The expects/exposes validations are for confirming that you're fulfilling your contract with yourself to call your service correctly. Any failures are not user facing (and in fact, at some point may optionally raise in development)

If you want to run validations on user-provided data (i.e. individual form elements), there's a Form Object pattern for that.