ActiveModel .normalize

normalize.rb

# frozen_string_literal: true

require "bundler/inline"

gemfile(true, quiet: true) do
  source "https://rubygems.org"

  git_source(:github) { |repo| "https://github.com/#{repo}.git" }

  gem "activesupport", "~> 7.0.0", require: false
  gem "activerecord", "~> 7.0.0", require: false
  gem "sqlite3"
end

require "active_support"
require "active_record"
require "minitest/autorun"
require "logger"

ActiveRecord::Base.establish_connection(adapter: "sqlite3", database: ":memory:")
ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord::Schema.define do
  create_table :users, force: true do |t|
    t.string :email
    t.string :alive
  end
end

class NormalizedType < DelegateClass(ActiveRecord::Type::Value)
  private attr_reader :normalizer, :allow_nil

  def initialize(subtype, normalizer, allow_nil: true)
    @normalizer = normalizer
    @allow_nil = allow_nil
    super(subtype)
  end

  def cast(value)
    super(value).then do |casted|
      next if casted.nil? && allow_nil

      normalizer.call(casted)
    end
  end

  def serialize(value)
    return super(value) if value.nil? && allow_nil

    super(normalizer.call(value))
  end

  def deserialize(value)
    super(value).then do |casted|
      next if casted.nil? && allow_nil

      normalizer.call(casted)
    end
  end
end

ActiveRecord::Base.extend(Module.new do
  def normalize(attr_name, proc, **options)
    attribute(attr_name) do
      NormalizedType.new(_1, proc, **options)
    end
  end
end)

class RawUser < ActiveRecord::Base
  self.table_name = "users"
end

class User < ActiveRecord::Base
  normalize :email, -> { _1.strip.downcase.presence }, allow_nil: true

  attribute :alive, :boolean

  validate :email_is_normalized

  private

  def email_is_normalized
    errors.add(:email, "has been normalized") unless email.match?(/[a-z1-9\.@\-]/)
  end
end

class SomeTest < Minitest::Test
  def setup
    ActiveRecord::Base.connection.execute "DELETE FROM users;"
  end

  def test_database
    user = User.create(email: " CRUISE-CONTROL@EXAMPLE.COM\n")
    assert_equal "cruise-control@example.com", user.email

    reloaded_user = User.find(user.id)
    assert_equal "cruise-control@example.com", reloaded_user.email
  end

  def test_from_user
    user = User.new(email: " CRUISE-CONTROL@EXAMPLE.COM\n")

    assert_equal "cruise-control@example.com", user.email
  end

  def test_queries
    user = User.create(email: " CRUISE-CONTROL@EXAMPLE.COM\n")

    assert_equal 1, User.where(email: " CRUISE-control@EXAMPLE.COM").count
    assert_equal user, User.find_by(email: " CRUISE-control@EXAMPLE.COM")
  end

  def test_reading_old_data
    raw_user = RawUser.create!(email: " CRUISE-CONTROL@EXAMPLE.COM\n", alive: 't')

    assert_equal " CRUISE-CONTROL@EXAMPLE.COM\n", raw_user.email
    assert_equal "t", raw_user.alive

    user = User.find(raw_user.id)

    assert_equal "cruise-control@example.com", user.email
    assert user.alive.eql?(true)
  end
end