Getting undefined local variable or method `tournament' when using round_robin_tournament gem

Question

I am trying to use the gem round_robin_tournament as described:

However I am getting the error:

undefined local variable or method `tournament' for #<# :0x00007ffb591d54a0>

I followed the description on in the readme section of that link. I am still new to Ruby on rails so it could be something simple :).

Here is my code:

Message_Controller.rb:

class MessagesController < ApplicationController
  before_filter :authenticate_user!

  def create
    @conversation = Conversation.find(params[:conversation_id])
    @message = @conversation.messages.build(message_params)
    @message.user_id = current_user.id
    @message.save!

    @path = conversation_path(@conversation)
  end

  private

  def message_params
    params.require(:message).permit(:body)
  end

  def tournament
    require "round_robin_tournament"

    # Compute all the possible teams for each day in the classroom
    students = %w(John Paul Ringo George)
    teams = RoundRobinTournament.schedule(students)

    # Print for each day, each team
    teams.each_with_index do |day, index|
      day_teams = day.map { |team| "(#{team.first}, #{team.last})" }.join(", ")
      puts "Day #{index + 1}: #{day_teams}"
    end

    # Day 1: (Paul, George), (Ringo, John)
    # Day 2: (Ringo, George), (John, Paul)
    # Day 3: (John, George), (Paul, Ringo)
  end
end

Routes.rb:

Rails.application.routes.draw do

  resources :posts
  resources :comments, only: [:create, :destroy]
  devise_for :users
  resources :users do
    member do
      get :friends
      get :followers
      get :deactivate
      get :mentionable
    end
  end

  resources :events do
    collection do
      get :calendar
    end
  end

  authenticated :user do
    root to: 'home#index', as: 'home'
  end
  unauthenticated :user do
    root 'home#front'
  end

  resources :conversations do
    resources :messages
  end

  match :follow, to: 'follows#create', as: :follow, via: :post
  match :unfollow, to: 'follows#destroy', as: :unfollow, via: :post
  match :like, to: 'likes#create', as: :like, via: :post
  match :unlike, to: 'likes#destroy', as: :unlike, via: :post
  match :find_friends, to: 'home#find_friends', as: :find_friends, via: :get
  match :about, to: 'home#about', as: :about, via: :get

  # The priority is based upon order of creation: first created -> highest priority.
  # See how all your routes lay out with "rake routes".

  # You can have the root of your site routed with "root"
  # root 'welcome#index'

  # Example of regular route:
  #   get 'products/:id' => 'catalog#view'

  # Example of named route that can be invoked with purchase_url(id: product.id)
  #   get 'products/:id/purchase' => 'catalog#purchase', as: :purchase

  # Example resource route (maps HTTP verbs to controller actions automatically):
  #   resources :products

  # Example resource route with options:
  #   resources :products do
  #     member do
  #       get 'short'
  #       post 'toggle'
  #     end
  #
  #     collection do
  #       get 'sold'
  #     end
  #   end

  # Example resource route with sub-resources:
  #   resources :products do
  #     resources :comments, :sales
  #     resource :seller
  #   end

  # Example resource route with more complex sub-resources:
  #   resources :products do
  #     resources :comments
  #     resources :sales do
  #       get 'recent', on: :collection
  #     end
  #   end

  # Example resource route with concerns:
  #   concern :toggleable do
  #     post 'toggle'
  #   end
  #   resources :posts, concerns: :toggleable
  #   resources :photos, concerns: :toggleable

  # Example resource route within a namespace:
  #   namespace :admin do
  #     # Directs /admin/products/* to Admin::ProductsController
  #     # (app/controllers/admin/products_controller.rb)
  #     resources :products
  #   end
end

index.html.erb:

<div class="row">
  <div class="col-lg-3">
    <%= render 'shared/user_info' %>
  </div>
  <div id="newsfeed" class="col-lg-6">
    <%= render 'posts/form' %>
    <br>
    <div id="activities">
      <% if @activities.empty? %>
        <div class="well">
          <%= render('shared/no_resource', resources: 'Activities') %>
        </div>
      <% else %>
        <%= render_activities(@activities, layout: '/shared/activity') %>
      <% end %>
    </div>
    <%= render 'shared/paginate', resources: @activities %>
  </div>
  <div class="col-lg-3">
    <%= render 'shared/links' %>
      <% @users.each_with_index do |user, index| %>
    <tr>
      <td><%= index +=1 %></td>
      <td><%= user.name %></td>
      <td>
        <%= link_to "Send Message", "#", class: "btn btn-success btn-xs start-conversation",
                    "data-sid" => current_user.id, "data-rip" => user.id %>
      </td>
    </tr>
<% end %>
  </div>

  <div>
    <%= tournament %>
  </div>
</div>

Thank you so much in advanced for the help.

New Code:

Controller:

class MessagesController < ApplicationController
  helper_method :tournament
  before_filter :authenticate_user!

  def create
    @conversation = Conversation.find(params[:conversation_id])
    @message = @conversation.messages.build(message_params)
    @message.user_id = current_user.id
    @message.save!

    @path = conversation_path(@conversation)
  end
  # controller
  def tournament
      require "round_robin_tournament"

      RoundRobinTournament.schedule %w(John Paul Ringo George)
  end

  private

  def message_params
    params.require(:message).permit(:body)
  end
end

View:

<div class="row">
  <div class="col-lg-3">
    <%= render 'shared/user_info' %>
  </div>
  <div id="newsfeed" class="col-lg-6">
    <%= render 'posts/form' %>
    <br>
    <div id="activities">
      <% if @activities.empty? %>
        <div class="well">
          <%= render('shared/no_resource', resources: 'Activities') %>
        </div>
      <% else %>
        <%= render_activities(@activities, layout: '/shared/activity') %>
      <% end %>
    </div>
    <%= render 'shared/paginate', resources: @activities %>
  </div>
  <div class="col-lg-3">
    <%= render 'shared/links' %>
      <% @users.each_with_index do |user, index| %>
    <tr>
      <td><%= index +=1 %></td>
      <td><%= user.name %></td>
      <td>
        <%= link_to "Send Message", "#", class: "btn btn-success btn-xs start-conversation",
                    "data-sid" => current_user.id, "data-rip" => user.id %>
      </td>
    </tr>
<% end %>
  </div>
<div>
<% tournament.each_with_index do |day, index| %>
  <% day_teams = day.map { |team| "(#{team.first}, #{team.last})" }.join(", ") %>

  <%= "Day #{index + 1}: #{day_teams}" %>
<% end %>
</div>
</div>

score 0 · Answer 1 · answered Mar 25 '18 at 05:25

This doesn't look like it has much to do with the gem at all, it's just that methods defined in the controller aren't accessible in the views, by default. You can tell rails to make a method available to the view by using helper_method though:

class MessagesController < ApplicationController
  helper_method :tournament

  # rest of your controller
end

I'm not sure if this will like the method being private or not (so if it doesn't work, try making the method public instead). Be aware also, that puts is still going to output to $stdout in rails, so if you want the output in the view you may want to just return teams from the method and then do that iteration in the view (untested, but will probably work):

# controller
def tournament
    require "round_robin_tournament"

    RoundRobinTournament.schedule %w(John Paul Ringo George)
end

# view
<% tournament.each_with_index do |day, index| %>
  <% day_teams = day.map { |team| "(#{team.first}, #{team.last})" }.join(", ") %>

  <%= "Day #{index + 1}: #{day_teams}" %>
<% end %>

Thanks for the help. I changed what you suggested but I am still getting the same issue. I edited my post to show the new code — Brandon Morales, Mar 25 '18 at 06:34

Getting undefined local variable or method `tournament' when using round_robin_tournament gem

1 Answers1