Setting up Controller for a reservations app - ruby-on-rails

Question

I am learning and building my first app with Ruby on Rails by cloning and adjusting an existing project. I got stuck in the writing a controller and hope that someone has a tip to help me out.
Context
I am building a trainings platform: Users can design a training, these trainings can be given on several dates (I call these trainingsessions 'thrills'), (other) users can subscribe to these thrills with reservations.
Conceptualization of models
Complication
I got the users, trainings and reservations model running now but I want to add the thrills model in between (I know this is not the easiest way, but I followed a training that did not include the thrills model). I setup the model and a simple view where a trainer should be able to add thrills to an existing training (in trainings/edit). Unfortunately after a day of trying I have not managed to do so, I keep getting:
NoMethodError in ThrillsController#create
NoMethodError (undefined method `thrills' for nil:NilClass): (line 16)
My TrainingsController for def edit looks like
def edit
if current_user.id == #training.user.id
#photos = #training.photos
#thrill = #training.thrills.create(thrill_params)
#thrills = #training.thrills
else
redirect_to root_path, notice: "Je hebt hier helaas geen toegang tot"
end
end
def update
if #training.update(training_params)
if params[:images]
params[:images].each do |image|
#training.photos.create(image: image)
end
end
#thrill = #training.thrills.create(thrill_params)
#thrills = #training.thrills
#photos = #training.photos
redirect_to edit_training_path(#training), notice: "Updated..."
else
render:edit
end
end
And my ThrillsController looks like
class ThrillsController < ApplicationController
def create
#thrill = #training.thrills.create(thrill_params)
redirect_to #thrill.training, notice: "Je thrill is aangemaakt!"
end
private
def thrill_params
params.require(:thrill).permit(:trilldate, :thrillhr, :thrillmin, :training_id)
end
end
And my form to add a thrill in views/thrills/_form.html.erb which is rendered in views/trainings/edit.html.erb
<%= form_for([#training.thrills.new]) do |f| %>
<div class="form-group">
<%= f.text_field :thrillhr, placeholder: "Uur", class: "form-control" %>
</div>
<%= f.hidden_field :training_id, value: #training.id %>
<div class="actions">
<%= f.submit "Create", class: "btn btn-primary" %>
</div>
<% end %>
The full code of the app can be found here https://github.com/chrisrutte/musc
Question
I'm obviously doing something simple wrong here, so I hope someone can provide me the hint how to save new thrills in my Thrills model.
If any more information is needed, don't hestitate to ask me.
Thanks in advance!

Answer 1

First lets look at what the models for this kind of setup would look like:
class Training < ActiveRecord::Base
has_many :thrills
has_many :users, through: :thrills
end
class Thrills < ActiveRecord::Base
belongs_to :training
has_many :reservations
has_many :users, through: :reservations
end
class Reservation < ActiveRecord::Base
belongs_to :user
belongs_to :thrill
has_one :training, though: :thrill
end
class User < ActiveRecord::Base
has_many :reservations
has_many :thrills, through: :reservations
has_many :trainings, through: :thrills
end
Make sure you read the Rails guide on associations as this is quite complex.
Notice that Reservation works as a join model.
Reservation also has an indirect relation to Training. This is to avoid having duplicate foreign keys on several levels. The same applies to the User model. The main reason is that ActiveRecord will only write the foreign key in once place!
When setting up the routes you will most likely want to use nesting:
resources :trainings, shallow: true do
resources :thrills
end
We can then setup the controller.
class ThrillsController < ApplicationController
before_action :set_training!, only: [:new, :create, :index]
before_action :set_thrill!, only: [:show, :edit, :update, :destroy]
# GET /trainings/:training_id/thrills/new
def new
#thrill = #training.thrills.new
end
# POST /trainings/:training_id/thrills
def create
#thrill = #training.thrills.new(thrill_params)
if #thrill.save
redirect_to #thrill
else
render :new
end
end
# GET /trainings/:training_id/thrills
def index
#thrills = #training.thrills
end
# this is not nested.
# GET /thrills/:id
def show
end
# this is not nested.
# GET /thrills/:id/edit
def edit
end
# this is not nested.
# PUT|PATCH /thrills/:id
def update
if #thrill.update(thrill_params)
redirect_to #thrill
else
render :edit
end
end
# ...
private
def set_training!
#training = Training.find(params[:training_id])
end
def set_thrill!
#thill = Thrill.joins(:training).find(params[:id])
#training = #thill.training
end
def thrill_params
params.require(:thrill)
.permit(:trilldate, :thrillhr, :thrillmin, :training_id)
end
end
And lets setup the form:
<%= form_for( [#training, #thrill] ) do |f| %>
<div class="form-group">
<%= f.text_field :thrillhr, placeholder: "Uur", class: "form-control" %>
</div>
<div class="actions">
<%= f.submit "Create", class: "btn btn-primary" %>
</div>
<% end %>
Since we want to pass the training_id though the form action attribute and not in the form body we use form_for( [#training, #thrill] ) which will give us the path /trainings/6/thrills for example.
However for our edit form we want /thrills/1 instead. So lets fix that:
<%= form_for( #thrill.new_record? ? [#training, #thrill] : #thrill ) do |f| %>
# ...
<% end %>