One of the tougher things to grasp in rails was nested routes. Nested routes and how to use those routes in with the actions. Also, how to use the parent and child relationships within forms and creating those new attributes. Crazy I know but trust me its a thing. So what im gonna do is show you a bit of what I struggled with in my rails project so maybe both you and I can understand it a bit better.
So first lets start with our relationships, mine has been great the last few years but there comes a time when.. oh wait nevermind. Wrong relationship. Uhhum anyways.. we have a user that can have many appointments, and many laboratories through appointments. And Same for laboratories, while an appointment can belong to a lab and a user. So here are my models for them.
*you can ignore the validates for now
class Appointment < ApplicationRecord
validates :type_of_appt, :appt_time, :appt_date, presence: true
belongs_to :user, optional: true
belongs_to :laboratory, optional: true
end
class Laboratory < ApplicationRecord
validates :name, :lab_type, :phone_number, :address, :lab_hours, :days_of_operation, presence: true
has_many :appointments
has_many :users, through: :appointments
end
class User < ApplicationRecord
has_many :appointments
has_many :laboratories, through: :appointments
accepts_nested_attributes_for :appointments, :allow_destroy => true
end
Ok. Next we can set up our nested routes in config/routes.rb as we need. We need appointments to be nested under user, so when you create the appointment you can create it on the current user. We will nest appointments with laboratories also.
*remember to add whichever actions you need in the only array
resources :users do
resources :appointments, only: [:index, :new, :create, :show, :edit, :destroy]
end
resources :laboratories do
resources :appointments, only: [:index, :show]
end
So far so good. Now we need to go to our controller(s) and create the actions that we need to use. We will need to make an action for each path. Ok, so in appointments controller, becuase thats the child resources nested in users resources, lets create the actions. I will explain them below. In this case, we will set up our actions in full to save time, but you get the idea.
*show all the users appointments in the index action
def index
@appointments = @user.appointments
end
*show the current appointment in the show action
def show
@appointment = Appointment.find(params[:id])
end
*instantiate a new appointment
def new
@appointment = Appointment.new
end
*create the new appointment with params
def create
@appointment = Appointment.create(appointments_params)
if @appointment.valid?
redirect_to user_appointment_path(@appointment.user, @appointment)
else
render :new
end
end
private
def appointments_params
params.require(:appointment).permit(:type_of_appt, :appt_time, :appt_date, :laboratory_id, laboratory_attributes:[:name, :lab_type, :phone_number, :address, :lab_hours, :days_of_operation] ).merge(user_id: current_user.id)
end
Finally, we need to create our views pages to use the actions right? Yes. (well I kinda lied, for now we will just do a nested form view but the other views are much easier trust me) When we are signed in as a user and creating a new appointment we need to also nest the parent and child in the form. However, I should add that we need to be able to select or create a laboratory when we create the appointment to associate all 3 at once. So here we have the @appointment nested in the @user form. What you are saying here pretty much is that the appointment you are creating is pertaining to that current user. And further down the form you are able to select a laboratory if it exists already by displaying all the laboratories with Laboratory.all and selecting with f.collection_select. If in any case the laboratory does not exist then you need to create a new one and that is where the fields_for comes in. You are setting up fields for the laboratory model by finding the current appointment being built, then iterating through the laboratories attributes to fill in each attribute.
<%= form_for [@user, @appointment] do |f| %>
<%= f.hidden_field :user_id %>
<%= f.label :type_of_appt %>
<%= f.text_field :type_of_appt %>
<br>
<%= f.label :appt_time %>
<%= f.text_field :appt_time %>
<br>
<%= f.label :appt_date %>
<%= f.text_field :appt_date %>
<br>
------------------------------------------
<p>Pick existing Lab</p>
<%= f.label :laboratory_id %>
<%= f.collection_select :laboratory_id, Laboratory.all, :id, :name, include_blank: "Choose" %>
<p>Or add a new Laboratory</p>
<%= f.fields_for :laboratory , @appointment.build_laboratory do |lab| %>
<%= lab.label :name%>
<%= lab.text_field :name %>
<br>
<%= lab.label :lab_type %>
<%= lab.text_field :lab_type %>
<br>
<%= lab.label :phone_number %>
<%= lab.text_field :phone_number %>
<br>
<%= lab.label :address %>
<%= lab.text_field :address %>
<br>
<%= lab.label :lab_hours %>
<%= lab.text_field :lab_hours %>
<br>
<%= lab.label :days_of_operation %>
<%= lab.text_field :days_of_operation %>
<br>
<% end %>
<br>
<%= f.submit %>
<% end %>
Ok so were done right. Not quite, but almost I promise. We need to tell the appointments model that we can have laboratory attributes created here. We do that by creating a method in the appointments model that allows that to happen.
this looks worse than it is, you are really just creating or finding a laboratory by all attributes
def laboratory_attributes=(laboratory_attributes)
if !laboratory_attributes[:name].empty?
laboratory = Laboratory.find_or_create_by(name: laboratory_attributes[:name],lab_type: laboratory_attributes[:lab_type], phone_number: laboratory_attributes[:phone_number], address: laboratory_attributes[:address], lab_hours: laboratory_attributes[:lab_hours], days_of_operation: laboratory_attributes[:days_of_operation])
laboratory.appointments << self
end
end
If you notice, our appointments controller params has a :laboratory_id, and laboratory_attributes:[:name, :lab_type, :phone_number, :address, :lab_hours, :days_of_operation] . That is becuase here we are allowing appointments to accept the laboratory_id or attributes in its params to create the new laboratory or find it! I know that’s a lot but I hope it comes in handy for some of you, and if some how no one reads it, then I can at least be happy with coming back to this in future jobs as a cheat sheet.