Adding before_validation and and after_validation hooks

[arushs]

First of all, StoreModel is awesome and we've been using it more and more in my teams project. We've been using it mostly for config type of data but I'm experimenting with using it for polymorphic records stored on a ActiveRecord model. One thing I think would be helpful (but maybe out of scope of this gem) is implementing before_validation and and after_validation hooks.

This could be useful in a number of ways. We could use before_validation to auto set values of fields. E.g. if we want to set randomly generated token as a unique identifier.

class FooStoreModel 
  include StoreModel::Model
  attribute :token, :string

  before_validation :set_token, on: :create


  private
    def set_token
      token = SecureRandom.uuid
    end
end

Another way this could be useful is for replicating STI type of inheritance. The polymorphic typing is awesome and I think it should conform to the Rails way of polymorphic STI (using a type variable).

class AbstractStoreModel 
  include StoreModel::Model
  attribute :type, :string

  before_validation :set_type, on: :create

  private
    def set_type
      type= self.class.name
    end
end

class FooStoreModel < AbstractStoreModel
end

class BarStoreModel < AbstractStoreModel
  attribute :value, :string
end


class FooRecord < ActiveRecord::Base
  StoreModelsType = StoreModel.one_of do |json|
    case json['type']
    when 'FooStoreModel'
      FooStoreModel
    when 'BarStoreModel'
      BarStoreModel
    else
      raise InvalidTypeError
    end
  end

  attribute :data, StoreModelsType.to_array_type
end

This would allow something like

  record = FooRecord.create!
  record.data << BarStoreModel.new(value: 'baz')
  record.save

which would auto cast and infer types

[DmitryTsepelev]

Hi @arushs, thanks for the great idea! I guess it will be a bit tricky, since before_validation is defined inside ActiveRecord::Callbacks module, and we do not need all these callbacks.

[adamzapasnik]

I think you can include ActiveModel::Validations::Callbacks https://api.rubyonrails.org/classes/ActiveModel/Validations/Callbacks.html and it should work correctly