Rack::OauthProxy

class BlogsController < ApplicationController
  use Rack::OauthProxy, url: "http://auth.example.com/oauth/token"

  before_action :require_authorization

  def show
    ...
  end

  private

  def require_authorization
    raise UnauthorizedError unless has_authorization?
  end

  # env["rack-oauth_proxy.response"] is a Faraday::Response object.
  def has_authorization?
    env["rack-oauth_proxy.response"].status == 200
  end
end