Rails 4从控制器执行关联的模型方法

Question

Let say we have a code:

Model:

class Dog < ActiveRecord::Base
  def self.make_noise
    puts 'bow-wow'
  end
end

Controller:

class DogsController < ApplicationController
  def index
    Dog.make_noise
  end
end

This will work, but I would rather like to write the controller index method code like: AssociatedModel.make_noise or Model.make_noise

Is it possible in Rails to call associated model method without using its class name in code?

This would be useful if I would like to use inheritance and make let say PetsController which will be the base for all pets (or a PetNoise Concern included for every applicable controller) and declare there index method.

I'm not sure if I explained this well enough.

OK. The one way (which i don't like) is to write PetsController method like this:

def index
  params[:controller].classify.constantize.make_noise
end

This way if I inherit PetsController from DogsController it will still work without defining separate index inside DogsController . But maybe there are other more neat solutions.

Answer 1

As I also explained in this answer , you can determine the model using params[:controller] . Like this:

params[:controller] # => "dogs"
params[:controller].classify # => "Dog"

Therefore you can write your index action "generically" like this:

def index
  model_class = params[:controller].classify.constantize
  model_class.make_noise
end