Module: ClassyEnum::ActiveRecord

Defined in:
lib/classy_enum/active_record.rb

Instance Method Summary collapse

Instance Method Details

#classy_enum_attr(attribute, options = {}) ⇒ Object

Class macro used to associate an enum with an attribute on an ActiveRecord model. This method is automatically added to all ActiveRecord models when the classy_enum gem is installed. Accepts an argument for the enum class to be associated with the model. ActiveRecord validation is automatically added to ensure that a value is one of its pre-defined enum members.

Example

# Associate an enum Priority with Alarm model's priority attribute
class Alarm < ActiveRecord::Base
  classy_enum_attr :priority
end

# Associate an enum Priority with Alarm model's alarm_priority attribute
classy_enum_attr :alarm_priority, :enum => 'Priority'

# Allow enum value to be nil
classy_enum_attr :priority, :allow_nil => true

# Allow enum value to be blank
classy_enum_attr :priority, :allow_blank => true

# Specifying a default enum value
classy_enum_attr :priority, :default => 'low'



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# File 'lib/classy_enum/active_record.rb', line 29

def classy_enum_attr(attribute, options={})
  enum              = (options[:enum] || attribute).to_s.camelize.constantize
  allow_blank       = options[:allow_blank] || false
  allow_nil         = options[:allow_nil] || false
  serialize_as_json = options[:serialize_as_json] || false
  default           = options[:default]

  if default.present?
    if default.is_a? Proc
      default = default.call(enum)
    end

    unless enum.include? default
      raise InvalidDefault, "must be one of [#{enum.to_a.join(',')}]"
    end
  end

  # Add ActiveRecord validation to ensure it won't be saved unless it's an option
  validates_inclusion_of attribute,
    :in          => enum,
    :allow_blank => allow_blank,
    :allow_nil   => allow_nil

  # Define getter method that returns a ClassyEnum instance
  define_method attribute do
    value = read_attribute(attribute) || default

    enum.build(value,
               :owner             => self,
               :serialize_as_json => serialize_as_json,
               :allow_blank       => (allow_blank || allow_nil)
              )
  end

  # Define setter method that accepts string, symbol, instance or class for member
  define_method "#{attribute}=" do |value|
    if value.class == Class && value < ClassyEnum::Base
      value = value.new.to_s
    elsif value.present?
      value = value.to_s
    end

    super(value)
  end
end