Better support for interactions that wrap another interaction or model.

[AaronLasseigne]

Goal

Reduce redundancy in interactions that wrap an underlying interaction or model. Often these are used in form objects and/or replace the CUD operations.

Areas of Redundancy

1. Filters
2. Validation

[AaronLasseigne]

Pulling validation information off of a model is basically impossible so whatever we do we'll have to send the values to the underlying model/interaction, run the validation, and merge the results back into the wrapping interaction.

[AaronLasseigne]

A thought I had recently is that it might be good to just create two new compose type methods that allow for the creation or updating of an AR model. Something like, new_model and update_model.

[tfausak]

How would that look?

class CreateThing < ActiveInteraction::Base
  # ...
  def execute
    new_model(Thing, inputs) # ?
  end
end

[AaronLasseigne]

Yup, something like that.

[tfausak]

For some reason I feel weird about adding helper methods for ActiveRecord specifically. ActiveInteraciton doesn't rely on ActiveRecord, only ActiveModel. A more general solution may be to pass an optional method parameter to compose. Or something else, I'm not sure.

I think it might help to see what you'd have to do to create a new record spelled out, before we try to compress it into a helper method.

class CreateThing < ActiveInteraction::Base
  # ...
  def execute
    thing = Thing.new(inputs)
    errors.merge!(thing) unless thing.save
    thing
  end
end

This assumes that the interaction inputs map one-to-one to the record's attributes. And that the record does not use protected attributes (attr_protected or attr_accessible).

[AaronLasseigne]

Right, the fact that this is a common pattern and we can provide an error mapping feature makes it worth consideration in my mind.

[tfausak]

Currently compose calls run, then checks valid?, then returns the result. If it fails, it goes with merge_errors_onto_base instead of just merge! (#87).

new_model would call new, then check save, then return itself. If it failed, it would use merge!.

Would it make sense to allow setting those things when calling compose?

# new_model
compose(Thing, inputs, run: :new, check: :save, return: :itself)

Heck, it could even take a proc.

[AaronLasseigne]

I could get on board with that.

[tfausak]

#291 (comment)

This has been open for more than a year. We've been getting along fine without it. No one else has asked for it. I think we don't need it.