Ruby on rails Rails 4跳过Rails.cache.fetch中的缓存

我的代码：

def my_method(path)
    Rails.cache.fetch(path, expires_in: 10.minutes, race_condition_ttl: 10) do
        # Calls Net::HTTP.get_response URI.parse path
        response = My::api.get path

        if response.status == 200
            JSON.parse response.body
        else
            nil # Here I need to prevent cache
        end
    end
end

当返回

nil

时，我不会缓存，但它会。。

---

在这种情况下，如何防止缓存？

一种不太优雅的方法是引发错误

def my_method(path)
  Rails.cache.fetch(path, expires_in: 10.minutes, race_condition_ttl: 10) do
    # Calls Net::HTTP.get_response URI.parse path
    response = My::api.get path

    raise MyCachePreventingError unless response.status == 200

    JSON.parse response.body
  end
rescue MyCachePreventingError
  nil
end

如果有人有更好的方法，我想知道另一种选择

def my_method(path)
    out = Rails.cache.fetch(path, expires_in: 10.minutes, race_condition_ttl: 10) do
        # Calls Net::HTTP.get_response URI.parse path
        response = My::api.get path

        if response.status == 200
            JSON.parse response.body
        else
            nil # Here I need to prevent cache
        end
    end
    Rails.cache.delete(path) if out.nil?
end