How to create and use a module using Ruby on Rails 3?

Question

I am using Ruby on Rails 3 and I would like to move some custom and shared code in a module.

1. What syntax should I use to write the module code?
2. In w

Answer 1

A>1. You can use the same syntax as any other ruby class. For instance, I'm defining a VehicleClassifer module which is going to use the classify_vehicle method to classify a vehicle based on the number of wheels it receives as an input.

module VehicleClassifer
  def classify_vehicle(number_of_wheels)
    VehicleType.where("number_of_wheels = ?", number_of_wheels)
  end
end

A>2. Modules are usually stored in the /lib folder.

questions 3,4,5 have more or less the same answer. you can use

class SomeController < ApplicationController
  include VehicleClassfier

  def index 
    classify_vehicle(4)  
  end
end

in the class you're using the module and you will have access to all the module's methods.

Also, In case you need to use a module through out your app, you can include it in your application controller.