A module that combines dry-initializer and dry-schema

schema_initializer.rb

require 'bundler/inline'
require 'json'

gemfile do
  source 'https://rubygems.org'
  
  gem 'dry-initializer'
  gem 'dry-schema'
end

# class User
#   include SchemaInitializer
#
#   schema do
#     required(:email).filled(:string)
#     required(:name).maybe(:string)
#     required(:is_admin).value(:bool?)
#   end
#
#   def to_s
#     "EMAIL=#{email} NAME=#{name} ADMIN=#{is_admin}"
#   end
# end
module SchemaInitializer
  def self.included(mod)
    mod.extend Dry::Initializer
    mod.extend ClassMethods
  end

  module ClassMethods
    def schema(&block)
      @schema = Dry::Schema.Params do
        instance_eval &block
      end
      instance_eval do
        @schema.rules.keys.each do |attr|
          option attr, optional: true
        end
      end
    end

    def process_kwargs(kwargs)
      result = @schema.call(kwargs)
      fail(ValidationError, result.errors.to_h.to_json) if result.failure?
      result.to_h
    end

    def new(**kwargs)
      super process_kwargs(kwargs)
    end
  end
  ValidationError = Class.new(StandardError)
end