Rails: different controller behavior based on route

Question

I am looking for best practice to solve the following situation:

I have an “additive” model, which should be many-to-many, related to some other models.

Examples:

# Meal-Model has_and_belongs_to_many :additives # Offer-Model has_and_belongs_to_many :additives # Additive-Model has_and_belongs_to_many :meals has_and_belongs_to_many :meals 

Routes are nested as follows:

 resources :offers do resources :additives end resources :meals do resources :additives end 

So, I get the urls like this:

 /offers/123/additives /meals/567/additives 

Both routes lead to the same controller action as additives#index . In AdditivesController, I check to see if options are available to select the data to retrieve:

 class AdditivesController < ApplicationController before_filter :offermealswitch # GET /restaurants/1/meals/123/additives # GET /restaurants/1/offers/123/additives def index @additives = @additivemeal.additives end def offermealswitch if params.has_key?(:meal_id) @additivemeal = Meal.find(params[:meal_id]) @type = "Meal" elsif params.has_key?(:offer_id) @additivemeal = Offer.find(params[:offer_id]) @type = "Offer" end end end 

Is this the right way to deal with this problem? It works very well, but I'm not sure if these are rails ... Thanks for your answers!

Answer 1

switching sigh to answer-space, so I can at least add a carriage return and make the code dumb.

I agree with the answer of fl00r, but add that you need to instantiate the object this way:

 @type = params[:type] @obj = @type.constantize.find(params["#{type}_id"]) @additives = @obj.additives 

Answer 2

EDIT regarding @Taryn East

 resources :offers do resources :additives, :type => "Offer" end resources :meals do resources :additives, :type => "Meal" end class AdditivesController < ApplicationController before_filter :find_additive def index @additives = @additive.additives end private def find_additive @type = params[:type] @additive = @type.constantize.find([@type, "id"].join("_")) # or "#{@type}_id", as you wish end end