Ruby-on-Rails 中的模型继承、工厂模式和自解析
我正在与一个网站合作，该网站将从许多不同的来源提取提要，然后将这些流保存到一个通用模型中，在本例中是一个特征。 FeedEntry 类中的代码示例可能是：
feed = Feedzirra::Feed.fetch_and_parse(feed_url)
add_entries(feed.entries)
...
def self.add_entries(entries)
entries.each do |entry|
# Should know how to parse itself into a trait
@trait = parse(entry)
if @trait.save
...
end
end
不可否认，我来自 java 背景，在 java 中，我将设置一个继承层次结构，然后在 FeedEntry 的每个子类上扩展 parse 方法，以便每个 FeedEntry 都知道如何解析自身。所以我的问题是：
1）这在rails中是一个可行的计划吗？
2) 如果是这样，是否只包含一列基本上是“类型”的列，表示 FeedEntry 是什么子类？
3）如果没有，有什么关于最干燥的方法的建议吗？
谢谢！
I am working with a site that will be pulling down feeds from a lot of different sources, and then saving those streams into a common model, in this case a trait. An example of the code from within the FeedEntry class might be:
feed = Feedzirra::Feed.fetch_and_parse(feed_url)
add_entries(feed.entries)
...
def self.add_entries(entries)
entries.each do |entry|
# Should know how to parse itself into a trait
@trait = parse(entry)
if @trait.save
...
end
end
Admittedly I come from a java background, and in java here, I would set up an inheritance heirarchy, and then on each subclass of FeedEntry extend the parse method so that each FeedEntry knew how to parse itself. So my questions:
1) Is this a feasible plan in rails?
2) If so, would one just include a column that was basically "type" that said what subclass the FeedEntry was?
3) If not, any suggestions on the DRYest way to do this?
Thanks!
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我认为你可以使用rails提供的单表继承。参考 ：
http://juixe.com/techknow /index.php/2006/06/03/rails-single-table-inheritance/ 和 http://api.rubyonrails.org/classes/ActiveRecord/Base.html 。
之后，您可以在每个“继承”类中添加解析方法。您可能想要添加 before_save 回调并调用 self.parse 。我不确定这是否是最干燥的方法..看看其他人怎么说会很有趣。
I think you can use Single table inheritance that rails provide . Refer :
http://juixe.com/techknow/index.php/2006/06/03/rails-single-table-inheritance/ and http://api.rubyonrails.org/classes/ActiveRecord/Base.html .
After that you could add the parse method in each one of your "inherited" classes . You might want to add a before_save callback and call self.parse . I am not sure if this is the DRYest way to do this .. would be interesting to see what others say .