Creating homes using nested routes - ruby-on-rails

Question

First this is all of my code
#models/user.rb
class User < ApplicationRecord
has_many :trips
has_many :homes, through: :trips
has_secure_password
accepts_nested_attributes_for :trips
accepts_nested_attributes_for :homes
validates :name, presence: true
validates :email, presence: true
validates :email, uniqueness: true
validates :password, presence: true
validates :password, confirmation: { case_sensitive: true }
end
#home.rb
class Home < ApplicationRecord
has_many :trips
has_many :users, through: :trips
validates :address, presence: true
end
class HomesController < ApplicationController
def show
#home = Home.find(params[:id])
end
def new
if params[:user_id]
#user = User.find_by(id: params[:user_id])
#home = #user.homes.build
end
end
def create
#user = User.find_by(id: params[:user_id])
binding.pry
#home = Home.new
end
private
def home_params
params.require(:home).permit(:address, :user_id)
end
end
I am trying to do something like this so that the home created is associated with the user that is creating it.
def create
#user = User.find_by(id: params[:user_id])
#home = Home.new(home_params)
if #home.save
#user.homes << #home
else
render :new
end
end
The problem is that the :user_id is not being passed into the params. So the #user comes out as nil. I can't find the reason why. Does this example make sense? Am I trying to set the associations correctly? Help or any insight would really be appreciated. Thanks in advance.

Answer 1

The way you would typically create resources as the current user is with an authentication such as Devise - not by nesting the resource. Instead you get the current user in the controller through the authentication system and build the resource off it:
resources :homes
class HomesController < ApplicationController
...
# GET /homes/new
def new
#home = current_user.homes.new
end
# POST /homes
def create
#home = current_user.homes.new(home_parameters)
if #home.save
redirect_to #home
else
render :new
end
end
...
end
This sets the user_id on the model (the Trip join model in this case) from the session or something like an access token when dealing with API's.
The reason you don't want to nest the resource when you're creating them as a specific user is that its trivial to pass another users id to create resources as another user. A session cookie is encrypted and thus much harder to tamper with and the same goes for authentication tokens.
by using if params[:user_id] and User.find_by(id: params[:user_id]) you are really just giving yourself potential nil errors and shooting yourself in the foot. If an action requires a user to be logged use a before_action callback to ensure they are authenticated and raise an error and bail (redirect the user to the sign in). Thats how authentication gems like Devise, Knock and Sorcery handle it.