Model: undefined local variable or method `current_user'

Question

I'm new to Rails, Rails_Admin and Devise. Trying to get current_user, which I thought should be provided by Devise, in a model:

class Item < ActiveRecord::Base
  attr_accessible :user_id
  belongs_to :user, :inverse_of => :items

  after_initialize do
    if new_record?      
      self.user_id = current_user.id unless self.user_id
    end                                
  end  
end

In Rails_Admin I get:

undefined local variable or method `current_user' for #<Item:0x007fc3bd9c4d60>

Same with

self.user_id = _current_user.id unless self.user_id

I saw there's a line in config/initializers/rails_admin.rb but not sure what it does:

  config.current_user_method { current_user } # auto-generated

Answer 1

current_user doesn't belong to model. This answer has some explanation.

Rails 3 devise, current_user is not accessible in a Model ?

Answer 2

You can't refer to current_user in the models because it is only available to Controllers and Views. This is because it's defined in ApplicationController. The way to get around this is to set the user attribute on Item when you create it in the controller.

class ItemsController < Application Controller

  def create
    @item = Item.new(params[:item])
    @item.user = current_user # You have access to current_user in the controller
    if @item.save
      flash[:success] = "You have successfully saved the Item."
      redirect_to @item
    else
      flash[:error] = "There was an error saving the Item."
      render :new
    end
  end
end

Additionally to make sure your Item isn't saved without the user attribute set, you can put a validation on the user_id. If it isn't set, the Item won't save to the database.

class Item < ActiveRecord::Base
  attr_accessible :user_id
  belongs_to :user,
             :inverse_of => :items # You probably don't need this inverse_of. In this
                                   # case, Rails can infer this automatically.

  validates :user_id,
            :presence => true
end

The validation in essence solves what you were trying to do when you were setting user in the model with the after_initialize callback. A guarantee that the Item isn't saved without that information.