module ActiveRecord module Attributes # :nodoc: extend ActiveSupport::Concern Type = ActiveRecord::Type included do class_attribute :user_provided_columns, instance_accessor: false # :internal: self.user_provided_columns = {} end module ClassMethods # Defines or overrides a attribute on this model. This allows customization of # Active Record's type casting behavior, as well as adding support for user defined # types. # # +name+ The name of the methods to define attribute methods for, and the column which # this will persist to. # # +cast_type+ A type object that contains information about how to type cast the value. # See the examples section for more information. # # ==== Options # The options hash accepts the following options: # # +default+ is the default value that the column should use on a new record. # # ==== Examples # # The type detected by Active Record can be overriden. # # # db/schema.rb # create_table :store_listings, force: true do |t| # t.decimal :price_in_cents # end # # # app/models/store_listing.rb # class StoreListing < ActiveRecord::Base # end # # store_listing = StoreListing.new(price_in_cents: '10.1') # # # before # store_listing.price_in_cents # => BigDecimal.new(10.1) # # class StoreListing < ActiveRecord::Base # attribute :price_in_cents, Type::Integer.new # end # # # after # store_listing.price_in_cents # => 10 # # Users may also define their own custom types, as long as they respond to the methods # defined on the value type. The `type_cast` method on your type object will be called # with values both from the database, and from your controllers. See # `ActiveRecord::Attributes::Type::Value` for the expected API. It is recommended that your # type objects inherit from an existing type, or the base value type. # # class MoneyType < ActiveRecord::Type::Integer # def type_cast(value) # if value.include?('$') # price_in_dollars = value.gsub(/\$/, '').to_f # price_in_dollars * 100 # else # value.to_i # end # end # end # # class StoreListing < ActiveRecord::Base # attribute :price_in_cents, MoneyType.new # end # # store_listing = StoreListing.new(price_in_cents: '$10.00') # store_listing.price_in_cents # => 1000 def attribute(name, cast_type, options = {}) name = name.to_s clear_caches_calculated_from_columns # Assign a new hash to ensure that subclasses do not share a hash self.user_provided_columns = user_provided_columns.merge(name => connection.new_column(name, options[:default], cast_type)) end # Returns an array of column objects for the table associated with this class. def columns @columns ||= add_user_provided_columns(connection.schema_cache.columns(table_name)) end # Returns a hash of column objects for the table associated with this class. def columns_hash @columns_hash ||= Hash[columns.map { |c| [c.name, c] }] end def reset_column_information # :nodoc: super clear_caches_calculated_from_columns end private def add_user_provided_columns(schema_columns) existing_columns = schema_columns.map do |column| user_provided_columns[column.name] || column end existing_column_names = existing_columns.map(&:name) new_columns = user_provided_columns.except(*existing_column_names).values existing_columns + new_columns end def clear_caches_calculated_from_columns @attributes_builder = nil @column_defaults = nil @column_names = nil @column_types = nil @columns = nil @columns_hash = nil @content_columns = nil @raw_column_defaults = nil end end end end