認証の習作: OmniAuth Google OAuth2 Strategy

usutani

外観

目的
ローカルの開発環境でGoogle OAuth2認証を行いたいと思います。
deviseなしでGoogle OAuth認証のサインインという投稿を参考にさせていただきました。

環境
macOS 10.15.4
Ruby 2.7.1
Rails 6.0.3.1
Yarn 1.22.4
Node 13.12.0
omniauth-google-oauth2 0.8.0

参照

リポジトリ
https://github.com/usutani/try_omniauth_google

Google APIs

参照先の手順通りに設定します。本家の説明に画像がなかったためとても参考になりました。感謝です。

実装

rails new -TM --skip-active-storage try_omniauth_google
cd try_omniauth_google
bundle add omniauth-google-oauth2
EDITOR=vim bin/rails credentials:edit

google:
  client_id: Google APIsの認証情報で発行されたクライアントID
  client_secret: Google APIsの認証情報で発行されたクライアントシークレット

bin/rails credentials:show
touch config/initializers/omniauth.rb

Rails.application.config.middleware.use OmniAuth::Builder do
  google = Rails.application.credentials.google
  provider :google_oauth2, google[:client_id], google[:client_secret]
end

bin/rails g model User provider uid name email image oauth_token oauth_expires_at:datetime
bin/rails db:migrate

bin/rails g controller Home index
bin/rails g controller Sessions new create destroy

config/routes.rb

Rails.application.routes.draw do
  root to: 'home#index'

  get 'auth/:provider/callback', to: 'sessions#create'
  get 'auth/failure', to: redirect('/')
  get 'signout', to: 'sessions#destroy', as: 'signout'

  resources :sessions, only: %i[new create destroy]
  resources :home, only: %i[index]
end

app/models/user.rb

class User < ApplicationRecord
  def self.from_omniauth(auth)
    where(provider: auth.provider, uid: auth.uid).first_or_initialize.tap do |user|
      user.provider = auth.provider
      user.uid = auth.uid
      user.name = auth.info.name
      user.email = auth.info.email
      user.image = auth.info.image
      user.oauth_token = auth.credentials.token
      user.oauth_expires_at = Time.at(auth.credentials.expires_at)
      return user
    end
  end
end

app/controllers/sessions_controller.rb

class SessionsController < ApplicationController
  def new
  end

  def create
    user = User.from_omniauth(request.env['omniauth.auth'])
    if user.save
      cookies.encrypted[:user_id] = user.id
      redirect_to root_url
    else
      redirect_to new_session_url
    end
  end

  def destroy
    cookies.delete(:user_id)
    redirect_to new_session_url
  end
end

app/controllers/application_controller.rb

class ApplicationController < ActionController::Base
  helper_method :current_user

  def current_user
    User.find(cookies.encrypted[:user_id]) if cookies.encrypted[:user_id]
  end
end

app/views/layouts/application.html.erb

  <body>
    <div>
      <% if current_user %>
        Signed in as <strong><%= current_user.name %></strong>!
        <%= link_to "Sign out", signout_path, id: "sign_out" %>
      <% end %>
    </div>

app/views/sessions/new.html.erb

<%= link_to "Sign in with Google", "/auth/google_oauth2", id: "sign_in" %>

bin/rails s
open http://localhost:3000/sessions/new

以上です。


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