我如何可以覆盖一个活动记录对象的属性赋值？ [英] How can I override the attribute assignment in an active record object?

问题描述

我知道你可以用虚拟属性做到这一点，但如果该列确实存在？

I know you can do this with virtual attributes, but what if the column actually exists?

例如，我的模型有一个 raw_topic 列。当 raw_topic 设置，我想艺术家和 SONG_TITLE 来根据掉 raw_topic 的内容设定。理想情况下，我想重写 raw_topic = 方法，但铁轨似乎不喜欢这样。

For example, my model has a raw_topic column. When raw_topic is set, I want artist and song_title to be set based off of raw_topic's contents. Ideally, I'd like to override the raw_topic= method, but rails doesn't seem to like that.

什么是这样做的正确方法？是一个回调的唯一途径？

What's the proper way of doing this? Is a callback the only way?

推荐答案

您可以做到这一点是这样的：

You can do it like this:

def raw_topic=(value)
  # do something with raw topic
  self[:raw_topic] = value
end

这样，你可以确保你仍然有原始的话题，如果你需要采取行动。

That way you can ensure you still have the raw topic if you need to act on it.

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