Creating "polymorphic" controller - ruby-on-rails

Question

Im working on adding voting to my app (like in Stackoveflow). I have two models Questions and Answers so i want to be able to vote for both of them. I see two ways to manage voting for different type of models:
Add concern for models, controllers and routes.
Add votes_controller that can handle voting for any model that has votable.
I`d like to use second way to solve my problem. But to use controller I will should pass two parameters to controller, like: votable_type: model-name, votable-id: object.id, and my route will look like: vote_up_vote_path, vote_down_vote_path.
Is there a way to use routes like: vote_up_path(answer); vote_down_path(question)?
And by passing object "vote_up_path (answer)" i want to be able to get it in controller
P.S. I`m not able to use gems. Gems provide logic for models, I'm already have this logic.
I found the solution. So at first we need to generate Votes controller.
$rg controller Votes
Than we add routes:
resource :vote, only: [:vote_up, :vote_down, :unvote] do
patch :vote_up, on: :member
patch :vote_down, on: :member
patch :unvote, on: :member
end
And add in votes_helper.rb:
module VotesHelper
def vote_up_path(votable)
{controller: "votes", action: "vote_up",
votable_id: votable.id, votable_type: votable.class}
end
def vote_down_path(votable)
{controller: "votes", action: "vote_down",
votable_id: votable.id, votable_type: votable.class}
end
def unvote_path(votable)
{controller: "votes", action: "unvote",
votable_id: votable.id, votable_type: votable.class}
end
end
Than we should add tests and complete our methods. In controller we can use this method to find our votable:
private
def set_votable
klass = params[:votable_type].to_s.capitalize.constantize
#votable = klass.find(params[:votable_id])
end

Answer 1

Highly recommend this gem to handle upvote/downvote:
Acts as votable

Answer 2

There are two ways to do this; the first is to use superclassed controllers, the second is to use an individual controller with a polymorphic model.
I'll detail both:
Superclassing
You can set a method in a "super" controller, which will be inherited by the answers and questions controllers respectively. This is kind of lame because it means you're sending requests to the answers or questions controllers (which is against the DRY (Don't Repeat Yourself) principle):
#config/routes.rb
resources :answers, :questions do
match :vote, via: [:post, :delete], on: :member
end
#app/controllers/votes_controller.rb
class VotesController < ApplicationController
def vote
if request.post?
# Upvote
elsif request.delete?
# Downvote
end
end
end
#app/controllers/answers_controller.rb
class AnswersController < VotesController
# Your controller as normal
end
... Even better ...
#app/controllers/application_controller.rb
class ApplicationController < ActionController::Base
def vote
...
end
end
#app/controllers/answers_controller.rb
class AnswersController < ApplicationController
....
end
This will allow you send the following:
<%= link_to "Upvote", answers_vote_path(#answer), method: :post %>
<%= link_to "Downvote", questions_vote_path(#question), method: :delete %>
-
The important factor here is that you need to ensure your vote logic is correct in the backend, which you'll then be able to use the vote method in the VotesController to get it working.
Polymorphic Model
Perhaps the simplest way will be to use a polymorphic model:
#app/models/vote.rb
class Vote < ActiveRecord::Base
belongs_to :voteable, polymorphic: true
end
#app/models/answer.rb
class Answer < ActiveRecord::Base
has_many :votes, as: :voteable
end
#app/models/vote.rb
class Vote < ActiveRecord::Base
has_many :votes, as: :voteable
end
This will allow you to do the following:
#config/routes.rb
resources vote, only: [] do
match ":voteable_type/:voteable_id", action: :vote, via: [:post,:delete], on: :collection #-> url.com/vote/answer/3
end
#app/controllers/votes_controller.rb
class VotesController < ApplicationController
def vote
if request.post?
#vote = Vote.create vote_params
elsif request.delete?
#vote = Vote.destroy vote_params
end
end
private
def vote_params
params.permit(:voteable_id, :voteable_type)
end
end
This would allow you to use the following:
<%= link_to "Vote", votes_path(:answer, #answer.id) %>