rails-auth

Rails Auth Homework

This evening, you will be building a User model for a Rails auth system. This project won't end in an app with login/logout functionality, but this is a concept that you will use over and over again.

Refer to the first auth reading and the second auth reading if you get stuck.

Phase 0: Creating a new rails project

• rails new app_name --database=postgresql

Phase 1: Create a User model and migration

• Pro-tip: You can generate a model and pre-populated migration from the command line by passing rails g model an options hash
  • Example: rails g model User username:string password_digest:string session_token:string
• Add the appropriate constraints and indices to the migration and run rails db:migrate
• Check schema.rb to make sure it worked

Phase 2: Add validations to the User model

• Validate the presence of username and session_token
• Validate the presence of password_digest and set the error message to Password can't be blank
• Validate the length of password, and set allow_nil to true
• Make sure that ensure_session_token gets called before_validation

Phase 3: Add helper methods to the User model

• Write ::find_by_credentials
  • This method takes in a username and a password and returns the user that matches
• Write ::generate_session_token
  • This is a helper method I like to write that uses SecureRandom::urlsafe_base64 and returns a 16-digit pseudorandom string
• Write #reset_session_token!
  • This method resets the user's session_token and saves the user
• Write #ensure_session_token
  • This method makes sure that the user has a session_token set, setting one if none exists
• Write #password=
  • This method sets @password equal to the argument given so that the appropriate validation can happen
  • This method also encrypts the argument given and saves it as this user's password_digest
  • Remember: you have to add an attr_reader for password for the validation to occur!

Phase 4: Check your work

• Check your model against the solutions.
• Try creating a user in the Rails console
  • Make sure your validations work, and also make sure that you're storing password_digest as an encrypted string

Example testing code below:

User.all # shows no users
empty_gage = User.new
empty_gage.save # rollback because of failed validations
password_too_short_gage = User.new(username: 'gage', password: 'test')
password_too_short_gage.save # rollback because of failed validations
gage = User.new(username: 'gage', password: 'testing')
gage.save # inserted into Users
User.all #<ActiveRecord::Relation [#<User id: 1, username: "gage"...
User.first.password_digest # shows a string of gibberish that you can't hack

Phase 5: Celebrate

• You have written an important part of a Rails auth system!