Accessing attributes from rails setter - ruby-on-rails-3

Question

I am kind of stuck trying to access (read) an attribute from a custom setter in Rails:
def password=(new_password)
puts self.firstname # returns nil
# Do other checks here before setting a hashed SCrypt password
end
The firstname is defined on the (user) object, however calling the firstname will not yield the value set. I need to read various attributes from the custom setter to do password checks up against firstname, lastname and email address.

Answer 1

Do you have the corresponding getter method?
def password
#password
end
Or if it's a really simple getter/setter pair just
:attr_accessor password
Update on your comment: so you're wanting to do something other than just set the attribute in the setter?
So obviously I have to advise against that. However you can just do something like:
def password=(new_password)
some_method(new_password)
#password = new_password
end
This will pass the new_password method out of the setter, allowing you to do other things with it, before setting the instance variable to the new value.
If you are trying to access the firstname attribute within the password setter, as in your example, you can do it this way:
def password=(new_password)
some_method(firstname)
#password = new_password
end
You don't use self to call the getter method.

Answer 2

Ok seems to be an issue with my app somewhere. I just did a minimal test application that works fine:
class User < ActiveRecord::Base
def password
password ||= SCrypt::Password.new(password_hash)
end
def password=(new_password)
logger.info 'DEBUG: self.lastname: ' + self.lastname.to_s
self.password_hash = SCrypt::Password.create(new_password, :key_len => 512, :salt_size => 32)
end
end
In console it works fine:
Loading development environment (Rails 3.2.12)
2.0.0-p0 :001 > u = User.new
=> #<User id: nil, firstname: nil, lastname: nil, password_hash: nil, created_at: nil, updated_at: nil>
2.0.0-p0 :002 > u.lastname = "Some Lastname"
=> "Some Lastname"
2.0.0-p0 :003 > u.password = 'test'
DEBUG: self.lastname: Some Lastname
=> "test"
So it seems to be some issue related to a gem / something / somewhere in the application and not a Rails specific problem. Apologies to the list.

Answer 3

The order of the params matters here based on what I have observed.
⚠️ Notice the order of :firstname and :password when passing.
If you're using params.require(:user).permit(:firstname, :password) and then passing it to your setters via .new or =setter methods. Then you can always access self.firstname in your password= setter method because you firstname got set first and it's available to access for next setters.
However, if you have params.require(:user).permit(:password, :firstname) then your password setter method cannot access self.firstname.