CSS colour validation in Rails 3

css_colour_validator.rb

# Put this file under Rails.root /lib

class CssColourValidator < ActiveModel::EachValidator
  def validate_each(record, attribute, value)
    return false unless value
    record.errors[attribute] << (options[:message] || 'is not a valid CSS colour') unless ::HexadecimalColourValidator.matches?(value) or ::WebSafeColourValidator.matches?(value)
  end
end

hexadecimal_colour_validator.rb

# Put this file under Rails.root /lib

class HexadecimalColourValidator < ActiveModel::EachValidator
  def validate_each(record, attribute, value)
    record.errors[attribute] << (options[:message] || 'is not a valid hexadecimal colour') unless self.class.matches?(value)
  end
  
  def self.matches?(value)
    return false unless value
    /^#(?:[0-9a-f]{3})(?:[0-9a-f]{3})?$/i.match(value).nil? ? false : true
  end
end

theme_element.rb

class ThemeElement < ActiveRecord::Base
  validates :value, :css_colour => true
end

web_safe_colour_validator.rb

# Put this file under Rails.root /lib

class WebSafeColourValidator < ActiveModel::EachValidator
  def validate_each(record, attribute, value)
    record.errors[attribute] << (options[:message] || 'is not a valid websafe colour') unless self.class.matches?(value)
  end
  
  def self.matches?(value)
    return false unless value
    %w(aliceblue antiquewhite aqua aquamarine azure beige bisque black blanchedalmond blue blueviolet brown burlywood cadetblue chartreuse chocolate coral cornflowerblue cornsilk crimson cyan darkblue darkcyan darkgoldenrod darkgray darkgrey darkgreen darkkhaki darkmagenta darkolivegreen darkorange darkorchid darkred darksalmon darkseagreen darkslateblue darkslategray darkslategrey darkturquoise darkviolet deeppink deepskyblue dimgray dimgrey dodgerblue firebrick floralwhite forestgreen fuchsia gainsboro ghostwhite gold goldenrod gray grey green greenyellow honeydew hotpink indianred indigo ivory khaki lavender lavenderblush lawngreen lemonchiffon lightblue lightcoral lightcyan lightgoldenrodyellow lightgray lightgrey lightgreen lightpink lightsalmon lightseagreen lightskyblue lightslategray lightslategrey lightsteelblue lightyellow lime limegreen linen magenta maroon mediumaquamarine mediumblue mediumorchid mediumpurple mediumseagreen mediumslateblue mediumspringgreen mediumturquoise mediumvioletred midnightblue mintcream mistyrose moccasin navajowhite navy oldlace olive olivedrab orange orangered orchid palegoldenrod palegreen paleturquoise palevioletred papayawhip peachpuff peru pink plum powderblue purple red rosybrown royalblue saddlebrown salmon sandybrown seagreen seashell sienna silver skyblue slateblue slategray slategrey snow springgreen steelblue tan teal thistle tomato turquoise violet wheat white whitesmoke yellow yellowgreen).include? value.downcase
  end
end