Getting Started with OAuth

application.yml

development:
  github_key: 710899dd3710a6a9814e
  github_secret: 102dc5253ae360eaae533e7dc5ceb46929dcbe4b

application_controller.rb

class ApplicationController < ActionController::Base
  # Prevent CSRF attacks by raising an exception.
  # For APIs, you may want to use :null_session instead.
  protect_from_forgery with: :exception

  helper_method :current_user

  def current_user
    @current_user ||= User.find(session[:user_id]) if session[:user_id]
  end

  def authorize!
    redirect_to root_path unless current_user
  end
end

dashboard.html.erb

<div class="container-fluid container-home">
  <div class="col-md-2"></div>
  <div class="col-md-8">
    <h1 class="home">You Are Authorized</h1>
    <%= image_tag current_user.image_url, class: "img-circle img-thumbnail home-image" %>
    <h2 class="home"> <%= current_user.nickname %> </h2>
    <h2 class="home"> <%= current_user.email %> </h2>
    <%= link_to "Logout", logout_path, method: :delete, class: "btn btn-lg btn-default btn-home" %>
  </div>
  <div class="col-md-2"></div>
</div>

omniauth.rb

Rails.application.config.middleware.use OmniAuth::Builder do
  provider :github, ENV['github_key'], ENV['github_secret']
end

sessions_controller.rb

class SessionsController < ApplicationController
  def create
    @user = User.find_or_create_from_auth(request.env['omniauth.auth'])
    if @user
      session[:user_id] = @user.id
      redirect_to dashboard_path
    else
      redirect_to root_path
    end
  end

  def destroy
    session.clear
    
    redirect_to root_path
  end
end

show.html.erb

<div class="container-fluid container-home">
  <div class="col-md-2"></div>
  <div class="col-md-8">
    <h1 class="home">You Are Authorized</h1>
    <%= image_tag current_user.image_url, class: "img-circle img-thumbnail home-image" %>
    <h2 class="home"> <%= current_user.nickname %> </h2>
    <h2 class="home"> <%= current_user.email %> </h2>
    <%= link_to "Logout", logout_path, method: :delete, class: "btn btn-lg btn-default btn-home" %>
  </div>
  <div class="col-md-2"></div>
</div>

user.rb

class User < ActiveRecord::Base
  def self.find_or_create_from_auth(auth)
    user = User.find_or_create_by(provider: auth.provider, uid: auth.provider)

    user.email     = auth.info.email
    user.nickname  = auth.info.nickname
    user.image_url = auth.info.image
    user.token     = auth.credentials.token
    user.save

    user
  end
end