Reusing code ruby on rails

Question

I've got a module in my project in lib/. it's content is like this :

module Search
  module Score

    def get_score
      return 'something'
    end

  end    
end

This Search has many different modules I need to use Score. I realize I need to add require in my model (I'm trying to use this from model). So here is my code (model) :

require 'search'

class User < ActiveRecord::Base

  def get_user_score
    #tried this :
    p Search::Score.get_score #error
    #this as well
    score_instance = Score.new #error
    score = Search::Score.get_score # error undefined method `get_score'
  end

end

So how do I reuse the code I have in other class (module)?

Mischa · Accepted Answer · 2013-03-14 14:16:07Z

2

To get it working you can either mix the module into your class:

require 'search'

class User < ActiveRecord::Base
  include Search::Score

  def get_user_score
    p get_score # => "something"
  end
end

Or you can define the method inside your module similar to class methods:

module Search
  module Score
    def self.get_score
      return 'something'
    end
  end    
end

If you do that, you can call get_score like expected:

require 'search'

class User < ActiveRecord::Base
  def get_user_score
    p Search::Score.get_score # => "something"
  end
end

See this tutorial for a more in depth explanation about modules in Ruby.

edited Mar 14, 2013 at 14:16

answered Mar 14, 2013 at 14:10

Mischa

43.4k9 gold badges101 silver badges111 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Community · Accepted Answer · 2017-05-23 12:22:01Z

0

First, see "Best Practices for reusing code between controllers in Ruby on Rails".

About reuse code as a module, take a look at "Rethinking code reuse with Modularity for Ruby".

edited May 23, 2017 at 12:22

CommunityBot

11 silver badge

answered Mar 14, 2013 at 13:56

Mihai8

3,1471 gold badge23 silver badges33 bronze badges

Comments

deepflame · Accepted Answer · 2013-03-14 14:10:33Z

0

"Modules are crippled classes"

Modules are like crippled classes in Ruby. If you look into the inheritance chain you see that a Class actually inherits from Module.

Module cannot be instanciated. So the call to .new is not working.

What you CAN do however is to specify your method as a 'class' method (I know I said it is not a class...)

So you would add a self in front like this:

module Search
  module Score

    def self.get_score
      return 'something'
    end

  end    
end

Then you can call this method as a class method like you tried in your code example

answered Mar 14, 2013 at 14:10

deepflame

9281 gold badge8 silver badges19 bronze badges

1 Comment

the Tin Man Over a year ago

I wouldn't call them anything like a crippled class. They are a very powerful feature with a great reason for existing and are key to what makes Ruby a cool language. Comparable and Enumerable are powerful modules that demonstrate what is good about modules.

the Tin Man · Accepted Answer · 2013-03-14 14:14:07Z

0

Search::Score is a module and not a class, so Score.new will not work.

You can try to change the signature of the get_score function to self.get_score.

edited Mar 14, 2013 at 14:14

the Tin Man

161k44 gold badges222 silver badges308 bronze badges

answered Mar 14, 2013 at 13:57

zwippie

15.6k3 gold badges44 silver badges58 bronze badges

Comments

johansenja · Accepted Answer · 2019-06-28 13:57:18Z

0

In addition to def self.get_score in the above answers, there is also extend self, like so:

module Search
  module Score
    extend self

    def get_score
      return 'something'
    end
  end    
end

and module_function:

module Search
  module Score
    module_function

    def get_score
      return 'something'
    end
  end    
end

The latter is actually the preferred method in RuboCop (source), though in practice I personally have not seen it so often.

answered Jun 28, 2019 at 13:57

johansenja

7382 gold badges9 silver badges19 bronze badges

Collectives™ on Stack Overflow

Reusing code ruby on rails

5 Answers 5

Comments

Comments

1 Comment

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

5 Answers 5

Comments

Comments

1 Comment

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related