# User Authentication in Rails

Devise is a very powerful gem, it allows you to sign up, sign in and sign out options just after installing. Moreover user can add authentications and restrictions to its applications. Devise also come with its own views, if user wants to use. A user can also customize sign up and sign in forms according to its need and requirement. It should be noted that Devise recommends that you implement your own login if you're new to rails.

# Authentication using Devise

Add gem to the Gemfile:

gem 'devise'

Then run the bundle install command.

Use command $ rails generate devise:install to generate required configuration file.

Set up the default URL options for the Devise mailer in each environment In development environment add this line:

config.action_mailer.default_url_options = { host: 'localhost', port: 3000 }

to your config/environments/development.rb

similarly in production this edit config/environments/production.rb file and add

config.action_mailer.default_url_options = { host: 'your-site-url'}

Then create a model using:$ rails generate devise USER Where USER is the class name for which you want to implement authentication.

Finally, run: rake db:migrate and you are all set.

# Custom views

If you need to configure your views, you can use the rails generate devise:views generator that will copy all views to your application. Then you can edit them as desired.

If you have more than one Devise model in your application (for example User and Admin), you will notice that Devise uses the same views for all models. Devise offers an easy way to customize views. Set config.scoped_views = true inside the config/initializers/devise.rb file.

You can also use the generator to create scoped views: rails generate devise:views users

If you would like to generate only a few sets of views, such as the ones for the registerable and confirmable module use the -v flag: rails generate devise:views -v registrations confirmations

# Devise Controller Filters & Helpers

To set up a controller with user authentication using devise, add this before_action: (assuming your devise model is 'User'):

before_action :authenticate_user!

To verify if a user is signed in, use the following helper:

user_signed_in?

For the current signed-in user, use this helper:

current_user

You can access the session for this scope:

user_session

  • Note that if your Devise model is called Member instead of User, replace user above with member

# Omniauth

First choose your auth strategy and add it to your Gemfile. You can find a list of strategies here: https://github.com/intridea/omniauth/wiki/List-of-Strategies

gem 'omniauth-github', :github => 'intridea/omniauth-github'
gem 'omniauth-openid', :github => 'intridea/omniauth-openid'

You can add this to your rails middleware like so:

Rails.application.config.middleware.use OmniAuth::Builder do
  require 'openid/store/filesystem' 
  provider :github, ENV['GITHUB_KEY'], ENV['GITHUB_SECRET']
  provider :openid, :store => OpenID::Store::Filesystem.new('/tmp')
end

By default, OmniAuth will add /auth/:provider to your routes and you can start by using these paths.

By default, if there is a failure, omniauth will redirect to /auth/failure

# has_secure_password

# Create User Model

rails generate model User email:string password_digest:string

# Add has_secure_password module to User model

user = User.new email: 'bob@bob.com', password: 'Password1', password_confirmation: 'Password1'

Verify password with authenticate method

user.authenticate('somepassword')  

# has_secure_token

Create User Model

# Schema: User(token:string, auth_token:string)
class User < ActiveRecord::Base
  has_secure_token
  has_secure_token :auth_token
end

Now when you create a new user a token and auth_token are automatically generated

user = User.new
user.save
user.token # => "pX27zsMN2ViQKta1bGfLmVJE"
user.auth_token # => "77TMHrHJFvFDwodq8w7Ev2m7"

You can update the tokens using regenerate_token and regenerate_auth_token

user.regenerate_token # => true
user.regenerate_auth_token # => true

# Remarks

At the time of generating devise configs using rails generate devise:install, devise will list out bunch of instructions on the terminal to follow.

If you already have a USER model, running this command rails generate devise USER will append necessary columns to your existing USER model.

Use this helper method before_action :authenticate_user! at the top of your controller to check whether user is logged-in or not. if not then they will be redirected to sign-in page.