How to maintain both admin and user with devise gem?(Rails 4) - ruby-on-rails

Question

I am using rails 4 with devise gem and following this article -"https://github.com/plataformatec/devise/wiki/How-To:-Add-an-Admin-Role", I created a model for admin also. Now I have both admin and user model. How can I get the current_admin as in application_helper, these are present:-
def resource_name
:user
end
def resource
#resource ||= User.new
end
def devise_mapping
#devise_mapping ||= Devise.mappings[:user]
end
Please help to main a admin session. Thanks in advance

Answer 1

Devise's current_X helper methods are defined like this:
def current_#{mapping}
#current_#{mapping} ||= warden.authenticate(scope: :#{mapping})
end
where mapping is the role type. *
As such, you should be able to access the current admin using:
current_admin
If this doesn't work, I would recommend checking to make sure that devise has been properly instanciated on the Admin model, as follows:
class Admin < ActiveRecord::Base
devise :database_authenticatable # additional attributes, i.e. :trackable, :lockable
end
*Source: Line 106 of https://github.com/plataformatec/devise/blob/master/lib/devise/controllers/helpers.rb
If you continue to experience issues with this, it might be worth reconsidering whether you need to separate administrators and users using different models, instead of simplifying both the model and the implementation by adding an administrative attribute to the users model.
Edit:
To give you an idea as to how much of a negligible performance difference there would be querying a single users table for administrative users vs having two tables, I seeded a MySQL database (running on XAMPP for OSX, so it is by no means heavily optimized) with 1000 user records, with only 2 of the users having 'isAdmin' set to true.
Query using SQL (Selecting Admins from a pool of 1000 Users):
SELECT * FROM `users` WHERE isAdmin = 1
Result:
Showing rows 0 - 1 (2 total, Query took 0.0004 seconds.)
Query using SQL (Selecting Admins from an Admin table):
SELECT * FROM `administrators`
Result:
Showing rows 0 - 16 (17 total, Query took 0.0003 seconds.)
This is by no means an incredibly thorough example - it was just to provide an idea as to the minimal difference when used like this. Active Record may be slightly quicker/slower, but I can't imagine it would be too different to the results above.
Personally, I find it easier to add an 'isAdmin' (or similar) attribute to my users model, like this:
Active Record migration (db\migrate\TIMESTAMP_create_users.rb)
class CreateUsers < ActiveRecord::Migration
def change
create_table :users do |t|
t.string :username
t.boolean :isAdmin, default: false
...
end
end
end
and then filter between Users and Administrators like so:
Users, except Admins
users = User.where(:isAdmin => false)
All users
allUsers = User.all
Admins only
admins = User.where(:isAdmin => true)