murdoch

Polymorphic Associations reversed

It's pretty easy to do polymorphic associations in Rails: A Picture can belong to either a BlogPost or an Article. But what if you need the relationship the other way around? A Picture, a Text and a Video can belong to an Article, and that article can find all media by calling @article.media

This example shows how to create an ArticleElement join model that handles the polymorphic relationship. To add fields that are common to all polymorphic models, add fields to the join model.

murdoch

class SelfMaker
  def yet_what_is_self?
    self.class.class_eval do
      mirror(self, "Inside class_eval of SelfMaker#yet_what_is_self?")
    end
    
    instance_eval do
      mirror(self, "Inside instance_eval of SelfMaker#yet_what_is_self?")
    end
    

murdoch

#Behold, the nav_link:

The nav_link helper works just like the standard Rails link_to helper, but adds a 'selected' class to your link (or its wrapper) if certain criteria are met. By default, if the link's destination url is the same url as the url of the current page, a default class of 'selected' is added to the link.

For full usage details, see: http://viget.com/extend/rails-selected-nav-link-helper

Drop nav_link_helper.rb into app/helpers in your Rails 3.x app and enjoy.

#About this fork