per_form_csrf_token

# File actionpack/lib/action_controller/metal/request_forgery_protection.rb, line 372
      def per_form_csrf_token(session, action_path, method)
        OpenSSL::HMAC.digest(
          OpenSSL::Digest::SHA256.new,
          real_csrf_token(session),
          [action_path, method.downcase].join("#")
        )
      end