How to access current_user variable in controller or model? - ruby-on-rails

Question

I have 1:N relationship between user and post model. I want to access user_id in post model. I tried it by accessing current_user but it's throwing cannot find current_user variable.
My userModel class:
class User < ActiveRecord::Base
devise :database_authenticatable, :registerable, :validatable
has_many :post
validates_format_of :email, with: /\A([^#\s]+)#((?:[-a-z0-9]+\.)+[a-z]{2,})\Z/i
end
MyPostModel class:
class Post < ActiveRecord::Base
belongs_to :user
before_create :fill_data
validates_presence_of :name, :message => 'Name field cannot be empty..'
def fill_data
self.is_delete = false
self.user_id = current_user # here I am getting the error
end
end
MyPostController class
class PostController < ApplicationController
before_action :authenticate_user!
def index
#post = Post.all
end
def new
#post = Post.new
end
def create
#post = Post.new(post_params)
if #post.save
redirect_to action: 'index'
else
render 'new'
end
end
.....
private
def post_params
params.require(:post).permit(:name,:user_id,:is_delete)
end
end
I can access the before_action :authenticate_user! in Post controller but not current_user in post model or controller. What I am doing wrong here in Post.fill_data. self.user_id?
Rest of the code is working fine and I can see the new entry of :name and :is_delete in sqlite3 database (when I am commenting self.user_id line in Post class).
Edit-1
I already have migration class for post
class CreatePosts < ActiveRecord::Migration
def change
create_table :posts do |t|
t.string :name
t.boolean :is_delete
t.references :user, index: true, foreign_key: true
t.timestamps null: false
end
end
end

Answer 1

In Rails your models should not be aware of the apps current user or any other state. They only need to know about themselves and the objects they are directly related to.
The controller on the other hand is aware of the current user.
So the proper way to do this would be to remove the fill_data callback from Post. And do it in the controller:
class PostController < ApplicationController
before_action :authenticate_user!
def index
#post = Post.all
end
def new
#post = current_user.posts.build
end
def create
#post = current_user.posts.build(post_params)
if #post.save
redirect_to action: 'index'
else
render 'new'
end
end
private
def post_params
params.require(:post).permit(:name,:user_id,:is_delete)
end
end
You should also set the default for your is_delete column in the database instead, but if you want to rock it like a pro use an enum instead.
Create a migration rails g migration AddStateToUsers and fill it with:
class AddStateToUsers < ActiveRecord::Migration
def change
add_column :users, :state, :integer, default: 0
remove_column :users, :is_delete
add_index :users, :state
end
end
We then use the rails enum macro to map state to a list of symbols:
class Post
enum state: [:draft, :published, :trashed]
# ...
end
That lets you do Post.trashed to get all posts in the trash or post.trashed? to check if a specific post is trashed.
notice that I use trashed instead of deleted because ActiveRecord has build in deleted? methods that we don't want to mess with.

Answer 2

You are trying to add current_user.id in post model using before_create call back. but better to do is use this
In posts_controller.rb
def new
#post = current_user.posts.new
end
def create
#post = current_user.posts.create(posts_params)
end
This will create a post for the current user.
Your fill_data method would be
def fill_data
self.is_delete = false
end