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Custom authentication in Ruby on Rails
When I was starting with Rails, I used to reach out to Devise every single time to handle the authentication. I thought myself to be a pro. You just need to install the gem
and run a few commands and there you have it. A working authentication system!
Soon after, I decided to build an invitation system, wherein the owner of the project could invite collaborators. To my surprise, there was a gem already, and that too, it was built for applications that were already using Devise. After fiddling with the gem, I realized that I was overriding most of the method
s just to get the functionality of the app that I desired. So after reading a handful of articles on authentication, I decided to build my own.
This article assumes that you have some basic understanding of how Rails works, what cookies are, and how cookie signing works.
Let's start with a fresh new rails app
rails new custom-authentication -T -d postgresqlcd custom-authentication
The -T
flag tells rails that we do not want the default test framework. We'll use RSpec
to test our application.
Installing the gems that we need
gem "bcrypt", "~> 3.1.7"group :development, :test do gem "factory_bot_rails", "~> 6.2" gem "rspec-rails", "~> 5.0", ">= 5.0.1" gem "shoulda-matchers", "~> 4.5", ">= 4.5.1"end
Add these gems to your Gemfile
if you don't have it already. We'll not be discussing what these gems do. Try googling and I'll promise you that you'll learn more about those gems from their official documentation.
Setting up the test suite
After installing the gems, run rails g rspec:install
. After successfully running the command, you should have the spec
directory at the root of your application.
Create a new directory called support
inside the spec
directory.
Within the spec/support/factory_bot.rb
, add these lines.
# spec/support/factory_bot.rbRSpec.configure do |config| config.include FactoryBot::Syntax::Methodsend
Within the spec/support/shoulda_matchers
, add these lines.
# spec/support/shoulda_matchers.rbShoulda::Matchers.configure do |config| config.integrate do |with| with.test_framework :rspec with.library :rails endend
These are steps in setting up our test framework so that we can leverage the method
s that the gems provide.
Now navigate to the spec/rails_helper.rb
and uncomment the line
Dir[Rails.root.join("spec/support/**/*.rb")].each { |f| require f }
which is usually found in line 27.
That should be it for now.
Creating a user model
Create a User
model so that we can store the users credentials and later use them to authenticate the user.
rails g model user email:string:uniq password:digest auth_token:string:uniq
You should have similar to these lines of code on your db/migrate/234235235_create_users.rb
. Run rails db:migrate
after that.
class CreateUsers < ActiveRecord::Migration[6.1] def change create_table :users do |t| t.string :email t.string :password_digest t.string :auth_token t.timestamps end add_index :users, :email, unique: true add_index :users, :auth_token, unique: true endend
We'll use the
auth_token
as a signed cookie.
Now navigate to spec/factories/users.rb
and let's set up the user
factory. In short, factories are a superset to the Rails fixtures.
# spec/factories/users.rbFactoryBot.define do factory :user do sequence(:email) { |n| "janethebest#{n}@example.com" } password { "secretpassword" } sequence(:auth_token) { |n| "secret_token#{n}" } endend
Now, we'll write some specs so that in the future when we modify parts of code, we can be sure that our application still functions as it's supposed to.
# spec/models/users_spec.rbrequire "rails_helper"RSpec.describe User, type: :model do subject(:user) { build(:user) } describe "validations" do it { is_expected.to have_secure_password } it { is_expected.to validate_presence_of(:email) } it { is_expected.to validate_length_of(:email).is_at_most(255) } it { is_expected.to validate_uniqueness_of(:email).case_insensitive } it { is_expected.to allow_value("[email protected]", "[email protected]").for(:email) } it { is_expected.not_to allow_value("johndoeexample.com", "johjn@exa").for(:email) } it { is_expected.to validate_length_of(:password).is_at_least(6) } end describe "callbacks" do it "normalizes the email before validation" do email = " [email protected] " user.email = email.upcase user.save! expect(user.email).to eq("[email protected]") end it "generates user auth_token at random" do user.auth_token = nil user.save! expect(user.auth_token).to be_present end endend
Run the tests, and it should fail.
Navigate to app/models/user.rb
and paste in those lines
class User < ApplicationRecord VALID_EMAIL_REGEX = /\A[\w+\-.]+@[a-z\d\-]+(\.[a-z\d\-]+)*\.[a-z]+\z/i has_secure_password has_secure_token :auth_token before_validation :normalize_email validates :email, presence: true, length: { maximum: 255 }, uniqueness: { case_sensitive: false }, format: { with: VALID_EMAIL_REGEX } validates :password, presence: true, length: { minimum: 6 }, allow_blank: true private def normalize_email self.email = email.to_s.strip.downcase endend
Run the tests again, and it should all pass. In short, what we're doing is that:
- We want to have a unique email address for every user and they should not be able to enter an invalid email address.
- We want to validate that the length of the password should at least be 6.
- We will be stripping out the whitespaces from the email address that the user enters through the form, and we will also be lowercasing it.
Note: If you notice that we are passing
allow_blank: true
on the password validation. If you are worrying that the user signing up will be able to set in nil or an empty string as their password, then do not.bcrypt
will automatically throw an error when this happens.The reason why we're doing that is to let the users not specify their password every single time they update their email address or their name.
I guess this is pretty much it for the user
model. Now let's move on to the users_controller
.
Creating a UsersController
Run rails g controller users
and navigate to the routes.rb
file.
Add,
resources :users, only: %i[create]
First, let's add some specs
for the users_controller
.
# spec/requests/users_spec.rbrequire "rails_helper"RSpec.describe "Users", type: :request do let(:valid_attributes) { { email: "[email protected]", password: "secretpass" } } let(:invalid_attributes) { { email: "[email protected]", password: "" } } describe "#create" do context "when the request is valid" do it "creates the user" do expect do post users_path, params: { user: valid_attributes } end.to change(User, :count).by(1) end it "stores the auth_token in the cookie" do post users_path, params: { user: valid_attributes } expect(signed_cookie[:auth_token]).to eq(User.first.auth_token) # You probably do not have the `signed_cookie` method end end context "when the request is invalid" do it "returns an error" do post users_path, params: { user: invalid_attributes } expect(json.dig(:errors, :password)).to be_present # You also do not have the `json` method. Let's add them first expect(response).to have_http_status(:unprocessable_entity) end end endend
Run the tests, and you'll probably get an error saying that you do not have the signed_cookie
and the json
method defined. Let's add them first.
# spec/support/requests/sessions_helper.rbmodule Requests module SessionsHelper def signed_cookie ActionDispatch::Cookies::CookieJar.build(request, cookies.to_hash).signed end endend
# spec/support/json_helper.rbmodule JsonHelper def json JSON.parse(response.body, symbolize_names: true) endend
Let's go to the rails_helper.rb
file and include
these module
s
# spec/rails_helper.rbRSpec.configure do |config| config.include JsonHelper config.include Requests::SessionsHelper, type: :requestend
After including the module
s, run the tests again and it should fail without complaining about the method not defined errors.
Navigate to the app/controllers/users_controller.rb
# app/controllers/users_controller.rbclass UsersController < ApplicationController def create user = User.new(user_params) if user.save cookies.signed.permanent[:auth_token] = user.auth_token # you could also set an expiring cookie that would expire after a certain time. # do your thing. Redirect? else render json: { errors: user.errors }, status: :unprocessable_entity end end private def user_params params.require(:user).permit(:email, :password) endend
Now, run the tests again and it should pass. We're done with signing up the user. Now let's focus on signing in the user.
Signing in the user
We'll be creating a Plain Old Ruby Object (PORO) to handle the core logic of the authentication, like finding the user
record and verifying if the password entered is correct or not.
Create a new file authentication.rb
under the app/models/
directory.
# app/models/authentication.rbclass Authentication def initialize(params) @email = params[:email].to_s.downcase @password = params[:password] end def user @user ||= User.find_by(email: @email) return unless @user @user.authenticate(@password) ? @user : nil end def authenticated? user.present? endend
Let's unit test this class
# spec/models/authentication_spec.rbrequire "rails_helper"RSpec.describe Authentication do describe "#user" do it "returns the user if present" do user = create(:user) auth = described_class.new(email: user.email, password: user.password) expect(auth.user).to eq(user) end it "returns the user for case insensitive email" do user = create(:user) auth = described_class.new(email: user.email.upcase, password: user.password) expect(auth.user).to eq(user) end it "returns nil if user is not found" do auth = described_class.new(email: "[email protected]", password: "password") expect(auth.user).to be_nil end it "returns nil if user's credentials do not match" do user = create(:user) auth = described_class.new(email: user.email, password: "invalidpassword") expect(auth.user).to be_nil end end describe "#authenticated?" do it "returns true if user is found" do user = create(:user) auth = described_class.new(email: user.email, password: user.password) expect(auth).to be_authenticated end it "returns false if user is not found" do auth = described_class.new(email: "[email protected]", password: "password") expect(auth).not_to be_authenticated end endend
Generating the SessionsController
Run rails g controller sessions
and navigate to the routes.rb
file.
resources :sessions, only: %i[create]
Navigate to the spec/requests/sessions_spec.rb
and let's write some specs.
# spec/requests/sessions_spec.rbrequire "rails_helper"RSpec.describe "Sessions", type: :request do describe "#create" do context "when the request is valid" do it "signs the user" do user = create(:user) post sessions_path, params: { email: user.email, password: user.password } expect(signed_cookie[:auth_token]).to eq(user.auth_token) end end context "when the request is invalid" do it "does not sign the user" do post sessions_path, params: { email: "[email protected]", password: "helloworld" } expect(signed_cookie[:auth_token]).to be_nil expect(json.dig(:errors, :invalid)).to be_present expect(response).to have_http_status(:unprocessable_entity) end end endend
Run the tests and it should fail. Let's get those specs passing!
# app/controllers/sessions_controller.rbclass SessionsController < ApplicationController def create auth = Authentication.new(params) # remember this class? if auth.authenticated? cookies.signed.permanent[:auth_token] = user.auth_token # do your thing. Redirect to some page? else render json: { errors: { invalid: ["credentials"] } }, status: :unprocessable_entity end endend
Run the tests again and it should all pass.
How the heck do we define the current_user
method now?
Devise and other libraries provide us a handful of helper methods such as current_user
, authenticate_user
, etc.
We'll do this the new way. We'll be leveraging the ActiveSupport::CurrentAttributes
class to make the authenticated user available globally. I know globals are controversial, but hey, why not for the sake of the tutorial.
Create a file current.rb
within the app/models/
directory.
# app/models/current.rbclass Current < ActiveSupport::CurrentAttributes attribute :userend
Now navigate to the application_controller.rb
file and add these lines.
# app/controllers/application_controller.rbbefore_action :set_current_userprivatedef set_current_user Current.user = User.find_by(auth_token: cookies.signed[:auth_token]) end
Now, after every single request, the set_current_user
method will fire up and will try to set the Current.user
.
For example:
- User signs up
- The cookie gets stored.
- The user gets redirected to another page.
- The
set_current_user
fires up and sets theCurrent.user
for you to be used in your app.
A quick note
- Since
Current.user
fires up in each request, please do not use it within your background jobs.
Conclusion
So there you have it. A fully working authentication system that you can customize to your needs. Although we did not write the views
, I assure you that it's pretty simple. Try fiddling with the system and you can come up with even better solutions.
That's it for now. Thank you for taking the time to read through. You rock!
Original Link: https://dev.to/abeidahmed/custom-authentication-in-ruby-on-rails-5cbc
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