sms-pager/app/controllers/oauths_controller.rb

class OauthsController < ApplicationController
  skip_before_action :require_login

  def oauth
    login_at(params[:provider])
  end

  def callback
    provider = params[:provider]
    @user = login_from(provider)

    if @user
      redirect_to root_path, notice: login_msg(@user, provider)
    else
      @user = auth_and_login(provider)
      redirect_to root_path, notice: login_msg(@user, provider)
    end
  end

  private

    def login_msg user, provider = 'oAuth'
      if user.active?
        "Logged in from #{provider.titleize}!"
      else
        "Your account must be activated by an administrator."
      end
    end

    def auth_and_login provider
      user = create_auth_from(provider, auth_info)
      reset_session # protect from session fixation attack
      auto_login(user) if user.active?
      user
    end

    def create_auth_from provider, auth
      user = Person.find_by_email auth[:user_info]["email"]
      user.authentications.create(provider: provider, uid: auth[:uid])
      user
    end

    def auth_info
      @auth_info ||= google_hash
    end

    def google_hash
      ga = Sorcery::Providers::Google.new
      ga.get_user_hash access_token
    end

    def auth_params
      params.permit(:code, :provider)
    end
end