In Uncle Bob's clean architecture, which Hanami is inspired by, Form Objects guard the boundary between Interactors and our delivery mechanism (typically an http endpoint).
In the Hanami docs, bounary guarding is done using params blocks in Actions (see here). This seems to couple validation to the http delivery mechanism. It seems more natural to me that Form Objects (or params black which accomplish the same thing) would live in delivery-mechanism-agnostic Interactors.
Unfortunately, I cannot figure out if Hanami supports such a design. I found a similar question on the Hanami forum, but it has no answer.
To clarify, below is a snippet of code demonstrating the kind of thing I want to do, but using Virtus and ActiveModel::Validations rather than Hanami facilities. For those familiar with Trailblazer, its contract block within its operations (its term for Interactor) is another example.
Finally, am I misunderstanding something about the intended use of Hanami? Hanami supports Interactors, so it seems like this should be possible...
require 'hanami/model'
require 'active_model'
require 'virtus'
class PersonForm
include Virtus.model
include ActiveModel::Validations
attribute :name, String
attribute :age, Integer
validates :name, :age, presence: true
def each
attributes.each {|a| yield a}
end
end
class Person
include Hanami::Entity
attributes :name, :age
end
# Code like this would then live inside of an Interactor, which
# can accept a params hash.
jonah_form = PersonForm.new({name: 'Jonah', age: '99'})
jonah = Person.new(jonah_form) if jonah_form.valid?
p jonah #=> <Person:0x007fbdde1edcc0 @id=nil @name="Jonah" @age=99>
# do stuff with our jonah entity
