using has_secure_password

For authentication, we need to do following three:

• to model, has_secure_password
• to table, password_digest
• bundle bcrypt gem

So, we add has_secure_password to User model,

  has_secure_password

and it requires gem ‘bcrypt-ruby’ to the Gemfile,

  gem 'bcrypt-ruby'

$ bundle install

it makes some gibberish for us. and then we add another column (by convention, name) password_digest.

$ rails generate migration add_password_digest_to_users

  add_column :users, :password_digest, 'string'

$ rake db:migrate

When we set password attribute to user instance like,

> user = User.find 1
> user.password = "open_sesame"
> user.password_confirmation = "open_sesame"
> user.save

For information, actually has_secure_password has its validation in it – A password attribute value (and a password_confirmation value are) required to save the object. Or we can

  has_secure_password validations: false

do this and put validation on model ourselves.

However, and then, the password_digest of the user now with data. (By the way it would get different value even if password the same.) From here we need to know

> user.authenticate("not_matching") 
=> false
> user.authenticate("open_sesame")  # matching
=> < ... >  # user object

and use it for authentication (or “log-in”) feature. That’s it!