How to begin using Dry-Validation and/with Dry-Struct

Support
6

Hi,

I was wondering exactly the same things - how to have the final output of Dry Validation be a Struct instead of hash of data?

I need the struct so that I can afterwards place it in a rails form.

My intention is the same as Trailblazer Reform - http://trailblazer.to/gems/reform/ - but Reform seems to be a bit behind right now, and I wanted to do something simple with just Dry Validation and Dry Struct.

I’ve done it using something along the lines of this, but I wonder if there’s an even more elegant way:

class ApplicationForm

  # Required dependency for ActiveModel::Errors
  extend ActiveModel::Naming
  extend ActiveModel::Translation

  attr_reader :errors

  def initialize(attributes = {})
    assign_attributes(attributes) if attributes
    @errors = ActiveModel::Errors.new(self)
  end

  def assign_attributes(attributes)
    attributes.each do |key, value|
      setter = :"#{key}="
      public_send(setter, value) if respond_to?(setter)
    end
  end

  class << self
    include Dry::Monads

    def validate(contract, params)
      outcome = contract.call(params)

      new.assign_attributes(outcome.to_h)
    end
end

and then I call it it with:

MyForm.validate(ValidationContract.new, params)