CODEWITHSUNDEEP
attributestokenrailstutorial.org
Nathan McKaskle
Nathan McKaskle

Reputation: 3083

Hartl Rails tutorial chapter 8: How does remember_token work?

In the Michael Hartl tutorial, chapter 8, we set up the sign in page and create a new column in the database to hold a base 64 string. In the tutorial it's called a remember_token. In the user.rb:

  private

    def create_remember_token
        self.remember_token = SecureRandom.urlsafe_base64
    end

self has a property called remember_token? Is this already built in or did it get created elsewhere? Maybe I'm just not understanding this very well.

He writes:

Because of the way Active Record synthesizes attributes based on database columns, without self the assignment would create a local variable called remember_token, which isn’t what we want at all. Using self ensures that assignment sets the user’s remember_token so that it will be written to the database along with the other attributes when the user is saved.

I'm confused, how did the user get a remember token? How does it know to write this to the database in that particular column?

In the user.rb you have the following code:

attr_accessible :name, :email, :password, :password_confirmation

There's nothing about remember_token there. How does it know to include this at User.save?

Upvotes: 1

Views: 1427

Answers (2)

user3574603
user3574603

Reputation: 3628

As of 2018, @remember_token has an accessor method.

https://www.railstutorial.org/book/advanced_login#code-user_model_remember

class User < ApplicationRecord
  attr_accessor :remember_token

  before_save { self.email = email.downcase }

  ...

# Remembers a user in the database for use in persistent sessions.
  def remember
    self.remember_token = User.new_token
    update_attribute(:remember_digest, User.digest(remember_token))
  end

  ...

There is no remember_token column in the database. It is a 'virtual' attribute. The remember token is stored as a hash as remember_digest instead.

Upvotes: 0

mhartl
mhartl

Reputation: 1931

In this context, self is a User object, and it has a remember_token attribute because of the database column created by the migration in Section 8.2.1 of the Ruby on Rails Tutorial. (Prepending self is necessary to assign to the attribute; without self, Ruby would just create a local variable called remember_token.)

Upvotes: 1

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