doorkeeper providerサンプルアプリに対応するOAuthクライアントをdeviseで作成した

module OmniAuth
  module Strategies
    class Doorkeeper < OmniAuth::Strategies::OAuth2
      option :name, :doorkeeper

      option :client_options, {
        site: 'http://localhost:4000',
        authorize_path: '/users/oauth/authorize'
      }

      uid do
        raw_info['id']
      end

      info do
        {
          email: raw_info['email'],
          name: raw_info['name'],
        }
      end

      def raw_info
        @raw_info ||= access_token.get('/api/v1/me.json').parsed || {}
      end
    end
  end
end

  config.omniauth :doorkeeper,  DOORKEEPER_APP_ID, DOORKEEPER_APP_SECRET, :client_options =>  {:site => DOORKEEPER_APP_URL}

  config.omniauth :doorkeeper, ENV['DOORKEEPER_APP_ID'], ENV['DOORKEEPER_APP_SECRET'], client_options: {site: ENV['DOORKEEPER_APP_URL'] }, scope: 'public write'

class Users::OmniauthCallbacksController < Devise::OmniauthCallbacksController
  # https://github.com/plataformatec/devise/issues/2432
  protect_from_forgery except: :doorkeeper
  skip_filter :auto_authenticate_omniauth_user!, only: :doorkeeper

  def doorkeeper
    # You need to implement the method below in your model (e.g. app/models/user.rb)
    oauth_data = request.env['omniauth.auth']
    @user = User.find_or_create_for_doorkeeper_oauth(oauth_data)
    session[:doorkeeper_token] = oauth_data['credentials']['token']

    if @user.persisted?
      sign_in_and_redirect @user, :event => :authentication #this will throw if @user is not activated
      if is_navigational_format?
        set_flash_message(:notice, :success, kind: ENV['DOORKEEPER_APP_NAME'] || 'Doorkeeper')
        # hide flash message after auto sign in
        #flash.delete(:notice)
      end
    else
      session['devise.doorkeeper_data'] = request.env['omniauth.auth']
      if respond_to?(:new_user_registration_url)
        redirect_to new_user_registration_url
      else
        redirect_to root_url
      end
    end
  end

  def after_omniauth_failure_path_for(scope)
    if respond_to?(:new_session_path)
      new_session_path(scope)
    else
      root_path
    end
  end
end

  devise_for :users, controllers: { omniauth_callbacks: 'users/omniauth_callbacks' }
  devise_scope :user do
    get 'sign_in',  to: 'devise/sessions#new',     as: :new_user_session
    __send__ Devise.sign_out_via, 'sign_out', to: 'devise/sessions#destroy', as: :destroy_user_session
  end

  # Default is 30 minutes.
  config.timeout_in = 1.minutes if Rails.env.development?
  config.expire_auth_token_on_timeout = true

  devise :omniauthable, omniauth_providers: [:doorkeeper]
  devise :timeoutable
  include DoorkeeperOauthFinder

module DoorkeeperOauthFinder
  extend ActiveSupport::Concern

  module ClassMethods
    def find_or_create_for_doorkeeper_oauth(oauth_data)
      uid = oauth_data.uid.to_s
      id = uid.to_i
      user = self.where(provider: oauth_data.provider, uid: uid).first
      if user
        user.name = oauth_data.info.name
        user.email = oauth_data.info.email
        user.save! if user.changed?
      else
        user = self.create!({
          id: id, # use same id
          name: oauth_data.info.name,
          provider: oauth_data.provider,
          uid: uid,
          email: oauth_data.info.email,
          #password: Devise.friendly_token[0,20]
        })
      end
      user
    end
  end
end

      ## Database authenticatable
      t.string :email,              null: false, default: ""
      # t.string :encrypted_password, null: false, default: ""

class AddOmniauthColumnsToUsers < ActiveRecord::Migration
  def change
    add_column :users, :provider, :string
    add_column :users, :uid, :string
    add_column :users, :name, :string
    add_index :users, [:provider, :uid], unique: true
  end
end

module DoorkeeperApiV1
  private

  def access_token
    return @access_token if defined?(@access_token)
    config = Devise.omniauth_configs[:doorkeeper]
    strategy = config.strategy_class.new(*config.args)
    token = session[:doorkeeper_token]
    @access_token = OAuth2::AccessToken.new(strategy.client, token)
  end

  def get_me
    access_token.get("/api/v1/me.json").parsed
  end

  def get_microposts
    access_token.get("/api/v1/microposts.json").parsed
  end

  MICROPOST_CONTENT_MAX_LENGTH = 140

  def post_micropost(micropost)
    micropost[:content] = micropost[:content].truncate(MICROPOST_CONTENT_MAX_LENGTH)
    access_token.post("/api/v1/microposts", params: { micropost: micropost }).parsed
  end
end

  include AuthDoorkeeper
  before_action :auto_authenticate_omniauth_user!

module AuthDoorkeeper
  private

  def auto_authenticate_omniauth_user!
    return if current_user
    session[:user_return_to] = request.original_url
    redirect_to main_app.user_omniauth_authorize_path(:doorkeeper)
  end
end