Authentication From Devise To A Django Database

Because of the awesomeness of the Rails Admin gem I recently had to connect a rails app using Devise to an existing Django application database. Django comes with a barebones admin much like padrino, and I’m sure there are Python libraries to extend the functionality of it. But I already know how to use Rails Admin and the process of creating a new rails app, getting the rails admin gem in and deploying on an ec2 instance through elastic beanstalk takes literally 5 minutes.

Obligatory beer pic. (this stuff is my jam lately, and comes in a 15 pack)

I should specify I’m using Rails 5.0, the Django application is 1.8.4

My first instinct was to reverse-engineer the Django authentication method to figure out the hashing scheme, then replicate it in Rails. Fortunately enough, after some hellacious googling I came across this tasty little gem pbkdf2_password_hasher. aherve had already done the heaving lifting for me! Cheers bro.

Here’s what my User model looks like:

class User < ApplicationRecord
	self.table_name = 'auth_user'

	devise :database_authenticatable, :registerable,
		:recoverable, :rememberable, :trackable, :validatable

	attr_accessor :encrypted_password, :current_sign_in_at, :remember_created_at, :last_sign_in_at,
		:current_sign_in_ip, :last_sign_in_ip, :sign_in_count

	def valid_password?(pwd)
		Pbkdf2PasswordHasher.check_password(pwd, self[:password])
	end

	def encrypted_password
		self[:password]
	end

	def encrypted_password=(pwd);end
end

Booyakasha.

Any fields that Devise might be trying to access that don’t exist, I simply added a attr_accessor for, except encrypted_password which I had to map to the existing hashed password field, in our case password.

I had to override Devise valid_password? method to return the result of the pbkdf2_password_hasher Pbkdf2PasswordHasher.check_password method.

Hope this helps somebody.