Module: ImmutableAttributes

Defined in:
lib/immutable_attributes.rb

Constant Summary collapse

VERSION = 
"1.0.3"

Instance Method Summary collapse

Instance Method Details

#attr_immutable(*args) ⇒ Object 



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# File 'lib/immutable_attributes.rb', line 14

def attr_immutable(*args)
  class_eval do
    args.each do |attr|
      define_method("#{attr}=") do |value|
        new_record? || read_attribute(attr).nil? ?
          write_attribute(attr, value) :
          raise(ActiveRecord::ImmutableAttributeError, "#{attr} is immutable!")
      end
    end
    # handle ActiveRecord::Base#[]=
    define_method :[]= do |attr, value|
      return write_attribute(attr, value) unless args.include?(attr.to_sym)
      send "#{attr}=", value
    end
  end
end

#validates_immutable(*attr_names) ⇒ Object 



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# File 'lib/immutable_attributes.rb', line 31

def validates_immutable(*attr_names)
  config = { :on => :update, :if => lambda {|x| true}, :message => "can't be changed" }
  config.update(attr_names.extract_options!)

  @immutables = attr_names

  attr_names.each do |attr|
    class_eval do
      define_method("original_#{attr}") do
        instance_variable_get("@original_#{attr}")
      end
    end
  end

  class_eval do
    def self.immutables
      @immutables
    end

    def after_initialize; end;

    def setup_originals
      self.class.immutables.each do |attr_name|
        next unless attribute_names.include? attr_name
        instance_variable_set("@original_#{attr_name}", send(attr_name.to_s))
      end
    end
    
    after_initialize :setup_originals
  end

  validates_each(attr_names, config) do |record, attr_name, value|
    next if record.send("original_#{attr_name.to_s}").nil?
    record.errors.add(attr_name, config[:message]) if record.send("original_#{attr_name.to_s}") != record.send(attr_name.to_s)
  end
end