Module: AttrEnumAccessor::ClassMethods

Defined in:
lib/attr_enum_accessor.rb

Instance Method Summary collapse

Instance Method Details

#attr_enum_accessor(enum_attribute, options = {}) ⇒ Object

Provides easy accessors for enumerated fields stored as integers in database.

Requires a column in the model to have :name_value (override with :value_column option)

Example:

class User < ActiveRecord::Base
  ROLE = {
    user:   1,
    editor: 2,
    admin:  3
  }

  include AttrEnumAccessor
  attr_enum_accessor :role, with: ROLE
  attr_enum_accessor :status, with: STATUS, value_column: :status_number, exclude_scope: true

end

u = User.new
u.role = :admin
u.role # => :admin
u.role_value # => 3

User.where_role(:admin).count                 # all admins
User.where_role([:editor, :admin]).count      # all editors and admins
User.where_role(ROLE.keys - [:admin]).count   # all except admins

User.role_to_value(:admin)            # => 3
User.role_to_value([:editor, :admin]) # => [2, 3]

Raises:

  • (ArgumentError) 


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# File 'lib/attr_enum_accessor.rb', line 37

def attr_enum_accessor(enum_attribute, options = {})
  enum_values = options[:with]
  value_column = options[:value_column] || :"#{enum_attribute}_value"
  raise ArgumentError.new("Required option `with` must be a Hash") unless enum_values.kind_of?(Hash)

  define_singleton_method(:"#{enum_attribute}_to_value") do |value|
    values = Array(value).flatten.map do |value|
      enum_values[value.to_sym] or raise ArgumentError.new("Invalid #{enum_attribute} `#{value}`")
    end
    values.count == 1 ? values.first : values
  end

  define_singleton_method(:"where_#{enum_attribute}") do |value|
    values = send(:"#{enum_attribute}_to_value", value)
    where(value_column => values)
  end unless options[:exclude_scope]

  define_method(enum_attribute) do
    enum_values.key(read_attribute(value_column))
  end

  define_method(:"#{enum_attribute}=") do |value|
    write_attribute(value_column, self.class.send(:"#{enum_attribute}_to_value", value))
  end
end