Identifique e associe seus modelos ActiveRecord usando UUIDs validados.
gem 'uuid'
gem 'activesupport'
gem 'activerecord'
gem 'sqlite3'
require 'active_support'
require 'active_record'
require 'uuid'
ActiveRecord::Base.establish_connection adapter: "sqlite3", database: ":memory:";
ActiveRecord::Schema.define do
self.verbose = false
create_table :posts, id: false, primary_key: :uuid do |t|
t.string :uuid, primary_key: true
t.string :title
t.text :content
t.timestamps
end
add_index :posts, :uuid
create_table :comments, id: false, primary_key: :uuid do |t|
t.string :uuid, primary_key: true
t.string :post_uuid
t.text :content
t.timestamps
end
add_index :comments, :uuid
add_index :comments, :post_uuid
end
ActiveRecord::Reflection::AssociationReflection.class_eval do
alias_method :derive_foreign_key_before_uses_uuids, :derive_foreign_key
def derive_foreign_key
key = derive_foreign_key_before_uses_uuids
active_record.respond_to?(:uses_uuids?) && active_record.uses_uuids? ? key.sub(/_id$/, '_uuid') : key
end
end
class UuidValidator < ActiveModel::EachValidator
def validate_each(record, attribute, value)
Uuid.new(value).valid_uuid? or
record.errors[attribute] << (options[:message] || "is not a valid UUID")
end
end
class Uuid
attr_reader :value
def self.build(uuid)
uuid.is_a?(Uuid) ? uuid : new(uuid)
end
def self.generate
new(UUID.new.generate)
end
def initialize(value)
@value = value.to_s
end
def valid_uuid?
@value =~ /A[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}z/
end
alias_method :to_s, :value
end
module UsesUuids
extend ActiveSupport::Concern
module SetsAfterInitialize
extend ActiveSupport::Concern
included do
after_initialize :set_uuid
end
end
module ActiveRecord
extend ActiveSupport::Concern
included do
validates_uniqueness_of :uuid
end
def write_attribute(attr_name, value)
_value = value.is_a?(Uuid) ? value.to_s : value
super(attr_name, _value)
end
def read_attribute_for_validation(key)
value = super
value.is_a?(Uuid) ? value.to_s : value
end
module ClassMethods
def primary_key
:uuid
end
def uses_uuids?
true
end
end
end
included do
validates :uuid, presence: true, uuid: true
end
def uuid
return nil unless self[:uuid]
@_uuid ||= Uuid.new(read_attribute(:uuid))
fail unless @_uuid.valid_uuid?
@_uuid
end
private
def set_uuid
self.uuid ||= Uuid.generate.to_s
end
end
class Record < ActiveRecord::Base
self.abstract_class = true
include UsesUuids
include UsesUuids::ActiveRecord
include UsesUuids::SetsAfterInitialize
end
class Post < Record
has_many :comments
end
class Comment < Record
belongs_to :post
end
post = Post.new
# => #<Post uuid: "e2cc2bd0-6d6e-0131-2bc8-38f6b1147145", title: nil, content: nil, created_at: nil, updated_at: nil>
Post.joins(:comments).to_sql
# => "SELECT "posts"".* FROM ""posts"" INNER JOIN ""comments"" ON ""comments"".""post_uuid"" = ""posts"".""uuid""""
Outra implementação digna de nota: https://github.com/jashmenn/activeuuid
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