Question

Suppose, I have a model

class Model < ActiveRecord::Base
  has_many :other_models
end

When some other code is loaded, e.g. some plugin or extension I want to modify this relation. I try this by just reopening the class:

class Model
  has_many :other_models, on_add: :method_on_add
end

But that doesn’t work. It uses only the options for the first relation. Any ideas how to accomplish this?

Answer 1

you can do metaprogramming; when some of your code is loaded; you can do as follow.

Model.class_eval do
  has_many :other_models
  # whatever you want to code
end

here is a good tutorial on metaprogrramming