How do a custom method applicable to various models - ruby-on-rails

Question

I have the following method called capitalizeEachWord. Inside this method there is an attribute called company
class BusCompany < ActiveRecord::Base
attr_accessible :company
before_save :capitalizeEachWord
validates :company,presence: true,
uniqueness: { case_sensitive: false },
format: /^([a-zA-z0-9]+\s?){1,}$/
def capitalizeEachWord
self.company=self.company.downcase.split.map(&:capitalize).join(' ')
end
end
I would like that this method not use the attribute company directly, but receives this attribute as a parameter for doesn't do it dependent of the model BusCompany. Something as the following. The problem is that this method I going to use in various models and don't want to write it in each model but use the inheritance
class BusCompany < ActiveRecord::Base
attr_accessible :company
before_save :capitalizeEachWord(self.company)
validates :company,presence: true,
uniqueness: { case_sensitive: false },
format: /^([a-zA-z0-9]+\s?){1,}$/
def capitalizeEachWord(attribute)
self.attribute=self.attribute.downcase.split.map(&:capitalize).join(' ')
end
end

Answer 1

Add the following code into config/initializers/capitalizer.rb
module Capitalizer
def self.included(base)
base.extend(ClassMethods)
end
module ClassMethods
def capitalize(*attributes)
#attributes_to_capitalize = attributes
before_save :capitalize_each_word
end
def attributes_to_capitalize
Array.new(#attributes_to_capitalize)
end
end
def capitalize_each_word
self.class.attributes_to_capitalize.each do |attr|
if value = send(attr)
self.send("#{attr}=", value.strip.titleize)
end
end
end
end
And then in your class:
class BusCompany < ActiveRecord::Base
include Capitalizer
capitalize :company
...
end

Answer 2

First, I'd recommend you override the setter for company instead of using error prone callbacks, like this:
class BusCompany < ActiveRecord::Base
# you can also use #titleize instead of capitalize each word
# also use try, in case `arg` is nil
def company=(arg)
super arg.try(:titleize)
end
end
Then you can use modules to wrap this functionality into a reusable unit. Throw this in a file in your concerns folder, or just in to the models folder:
module CapitalizedSetter
def capitalize_setter(*attr_names)
# for each attr name, redifine the setter so it supers the titleized argument instead
attr_names.each do |attr|
define_method(:"#{attr}=") { |arg| super arg.try(:titleize) }
end
end
end
Finally extend it into the desired models:
class BusCompany
extend CapitalizedSetter
capitalized_setter :company
end