Rails authentication from scratch, skip current password validation - ruby-on-rails

Question

I have an auth system from scratch, and when a user clicks on 'edit profile' it has to input the current password no matter the field he wants to edit.
def update
if params[:user][:password].present?
authenticated = #user.authenticate(params[:user][:current_password])
if authenticated && #user.update(user_params)
redirect_to root_url
flash[:notice] = "Your profile was successfully updated!"
else
#user.errors.add(:current_password, 'is invalid') unless authenticated
render :edit
end
elsif #user.update(user_params)
redirect_to root_url
flash[:notice] = "Your profile was successfully updated!"
else
render :edit
end
end
How can I call authenticate or use some context model validation only for the scenario when the user wants to change his password?

Answer 1

I wouldn't recommend mixing this logic into the model because you end up with complexity that is hard to follow as your application grows over time.
Try taking a look into form objects:
Form-backing objects for fun and profit
Railscast #416 Form Objects [paid subscription required]
I'd implement something like this:
class UserUpdateForm
include ActiveModel::Model
# Attributes
attr_accessor :user, :new_password, :new_password_confirmation
# Validations
validates :current_password, if: :new_password
validate :authenticate, if: :current_password
validates :new_password, confirmation: true, allow_blank: true
def initialize(user)
self.user = user
end
def submit(params)
self.new_password = params[:new_password]
self.new_password_confirmation = params[:new_password_confirmation]
if self.valid?
# Set other attributes as needed, then set new password below.
self.user.password = self.new_password if self.new_password.present?
self.user.save
else
false
end
end
private
def authenticate
unless self.authenticate(self.current_password)
self.errors.add(:current_password, 'is invalid')
end
end
end
Then you can call it from your controller like so:
def update
#user_update_form = UserUpdateForm.new(#user)
if #user_update_form.submit(params)
flash[:notice] = "Your profile was successfully updated!"
redirect_to root_url
else
render :edit
end
end
See the links above for how to handle the view and such. This is just to get you started.

Answer 2

You may create a nested if-else in this action statement that will check for existence of new_password and new_password_confirmation (or whatever the new password and confirmation fields are called) in the params[:user] object. If they are present - you may redirect to some king of page with request to enter existent password.
Another way is to use ajax to show asynchronously the dialog box with the same request (like respond_with self-invoking javascript function that handles that). Then handle submit button in of the dialog in the other action of the controller.
Update (considering use of validators):
Considering validation you may write your own validator (for password) and condition to check when the new password field come with some data from the client.
I think it could look like this:
validate :password_update?
def password_update?
if new_password.present?
if current_password !== self.password
errors.add(:current_password, "must be supplied!")
else
# update data and password
end
else
# do your regular update
end
end