Rails lib directory

Question about lib directory.

开发者_如何学编程What are good practices in using the lib directory?

When should it be used over app/models or app/helpers?

And somewhat related how do you get Rails 3 to include files from the lib directory?

Thanks

---

One use of the lib directory (how I use it most often) is to share code between models to stay DRY. For example, if you are defining a tag_tokens attribute on many different models for use with a tokenizer input, you could put that in "tag_accessor.rb" or something, place it in /lib', and then include it with include TagAccessor. The ruby file might look like:

module TagAccessor
  def tag_tokens
    tags.map(&:name).join(',')
  end

  def tag_tokens=(names)
    self.tag_ids = names.split(",").uniq
  end
end

(This is an example from one of my apps, which is why it's so specific). Then to load the /lib folder in Rails 3, place this in your application.rb:

 config.autoload_paths += %W(#{config.root}/lib)