I want to override authenticate_user! and current_user method of devise gem in my application Controller can you please help me with regards to that Thanks
On overriding how a user is authenticated:
Devise uses Warden under the hood https://github.com/plataformatec/devise/blob/master/lib/devise/controllers/helpers.rb
So you can just add a new strategy in Warden to authenticate your users. See https://github.com/hassox/warden/wiki/Strategies
You should not need to override current_user. What challenge are you facing ? Do you need a different model returned ?