How do I use acts_as_votable on a nested resource that's displayed within the view for another model? E.g. in a Q&A context

Question

I have a Question model and an Answer model. In the Question Show view, I use a loop to display all answers to the given question. I want to enable voting on these answers. I'm using the acts_as_votable gem.

Here's the error I'm getting when I load "/questions/1":

No route matches {:action=>"upvote", :controller=>"answers", :id=>nil, :question_id=>"1"} missing  required keys: [:id]

Seems like the answer :id isn't being detected, and thus it isn't finding a matching route (e.g. /questions/1/answers/1/like). What am I doing wrong here?

The weird thing is that the voting works perfectly within the Answers index view, using the same code. So I suspect it's something about trying to use this code via the Questions controller and views. This is probably an obvious problem, but thanks for any tips!

My nested routes:

resources :questions do
  resources :answers do
    member do
      put 'like', to: 'answers#upvote'
      put 'dislike', to: 'answers#downvote'
    end
  end
end

My Answers Controller - upvote/downvote actions:

def upvote
     @question = Question.find(params[:question_id])
     @answer = @question.answers.find(params[:id])
     @answer.upvote_by current_user
     redirect_to question_answers_path(@question)
 end

 def downvote
    @question = Question.find(params[:question_id])
    @answer = @question.answers.find(params[:id])
    @answer.downvote_by current_user
    redirect_to question_answers_path(@question)
 end

My Questions Show view (eventually I'll make this a partial)

<% @question.answers.each do |answer| %>
  <li class="answer-item">
     <div class="answer-description">
        <%= answer.description %>          
     </div>
     <div class="vote">
        <div class="col-xs-3">
          <%= link_to 'UP', like_question_answer_path(@question, answer), method: :put %>
        </div>
        <div class="col-xs-9">
        </div>
     </div>
   </li>

My routes:

    like_question_answer PUT    /questions/:question_id/answers/:id/like(.:format)    answers#upvote
dislike_question_answer  PUT    /questions/:question_id/answers/:id/dislike(.:format)  answers#downvote
       question_answers  GET    /questions/:question_id/answers(.:format)             answers#index
                         POST   /questions/:question_id/answers(.:format)             answers#create
    new_question_answer  GET    /questions/:question_id/answers/new(.:format)         answers#new
   edit_question_answer  GET    /questions/:question_id/answers/:id/edit(.:format)    answers#edit
        question_answer  GET    /questions/:question_id/answers/:id(.:format)         answers#show
                         PATCH  /questions/:question_id/answers/:id(.:format)         answers#update
                         PUT    /questions/:question_id/answers/:id(.:format)         answers#update
                         DELETE /questions/:question_id/answers/:id(.:format)         answers#destroy
            questions    GET    /questions(.:format)                                 questions#index
                         POST   /questions(.:format)                                 questions#create
            new_question GET    /questions/new(.:format)                             questions#new
           edit_question GET    /questions/:id/edit(.:format)                        questions#edit
                question GET    /questions/:id(.:format)                             questions#show
                         PATCH  /questions/:id(.:format)                             questions#update
                         PUT    /questions/:id(.:format)                             questions#update
                         DELETE /questions/:id(.:format)                             questions#destroy

Answer 1

No route matches {:action=>"upvote", :controller=>"answers", :id=>nil, :question_id=>"1"} missing  required keys: [:id]

This error message is telling you everything you need to know. When you are in the answers view an id (Answer Id) is being passed to the Answers controller but when you are in the questions view there is no answer id to populate that parameter of the request. Because the parameter is absent it doesn't match the regex of the route.

PUT questions/1/answers/1/like

Must have the ids that are part of the request.

EDIT Assuming that you have an existing question and answer record. If you change the following line do you get an error?

<%= link_to 'UP', like_question_answer_path(Question.first, Answer.first), method: :put %>