Twitter OAuth

auth_controller.rb

class AuthController < ApplicationController
  OAUTH_SITE = "https://api.twitter.com"
  REQUEST_TOKEN_URL = "https://api.twitter.com/oauth/request_token";
  AUTHORIZE_URL = "https://api.twitter.com/oauth/authenticate";
  ACCESS_TOKEN_URL = "https://api.twitter.com/oauth/access_token";

  CONSUMER_KEY = "xxx"
  CONSUMER_SECRET = "xxx"

  before_action :consumer, only: [:twitter]

  def twitter
    if session[:access_token]
      redirect_to news_index_url
      return
    end
    request_token = @consumer.get_request_token(oauth_callback: CALLBACK_URL)
    session[:request_token] = request_token
    redirect_to request_token.authorize_url
  end

  def callback
    request_token = session[:request_token]
    unless request_token
      redirect_to news_index_url
      return
    end
    access_token = request_token.get_access_token(oauth_verifier: params[:oauth_verifier])
    session[:access_token] = access_token
    # 初回ユーザ登録
    User.where(twitter_id: access_token.params[:user_id]).first_or_create
    redirect_to news_index_url
  end

  def logout
    reset_session
    redirect_to news_index_url
  end

  private

  def consumer
    @consumer = OAuth::Consumer.new(CONSUMER_KEY, CONSUMER_SECRET, {
        site: OAUTH_SITE,
        request_token_path: "/oauth/request_token",
        authorize_path: "/oauth/authenticate",
        access_token_path: "/oauth/access_token",
      }
    )
  end
end