Ruby (Rails) variable scope

Question

I'm quite new with Ruby language and Rails. I'm currently building some simple user registration process. When I used these codes Rails throws: no implicit conversion from nil to string

Here's the original code:

require 'digest'

class User < ActiveRecord::Base
  before_save :encrypt_password

  protected
  def encrypt_password
    return if password.blank?
    password = encrypt(password)
  end

  def encrypt(string)
    Digest::SHA1.hexdigest(string)
  end
end

But it works if I changed this line password = encrypt(password), to self.password = encrypt(password). I'm just curious, what's wrong with the first code?

You should also read through http://www.techotopia.com/index.php/Ruby_Variable_Scope — benathon, Jan 15 '14 at 07:51
http://stackoverflow.com/questions/5183664/why-isnt-self-always-needed-in-ruby-rails-activerecord — Ivan Denysov, Jan 15 '14 at 07:51

score 3 · Answer 1 · answered Jan 15 '14 at 07:50

3

Ruby doesn't allow using implicit self. with the person= type of method.
That is because it considers you're setting a local variable. So it doesn't relies on self.

You need to explicitely specify self.password =.

answered Jan 15 '14 at 07:50

Damien MATHIEU

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Ruby (Rails) variable scope

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