ruby on rails - What is the best way to create a DRY content model hierarchy? -

i have content management system ios app built rails. right there 3 different types of content. first 2 strings uploaded textfield user. 1 twitter handles , hashtags, other urls. second type photos.

the user can upload many individual instances of these types content he/she wants given feed passed ios app via api call display.

the current approach using have feed, picture, twitter, , webpage models. when user crates new feed, associate appropriate content feed via 1 many relationship between each feed instance it's content instances.

when comes time display content user has uploaded, request given stream generated , feed model following awful thing determine type of content should shown:

 def feed.get_content_for_feed(feed_id)     return self.map_type_to_class(feed_id).get_content_for_feed(feed_id)   end    private    def feed.map_type_to_class(feed_id)     feed_type_id = feed.find(feed_id).feed_type_id     not_yet_implemented = nil     case stream_type_id       when 1         return webpages       when 2         return pictures       when 3         return not_yet_implemented       when 4         return twitter       when 5         return not_yet_implemented       when 6         return not_yet_implemented       when 7         return not_yet_implemented       when 8         return not_yet_implemented       else         return nil      end   end 

then each content class implements get_content_for_feed method return content:

def twitter.get_content_for_feed(feed_id)     tweet_urls = self.where(:feed_id => feed_id.to_i)     if tweet_urls.empty?       return []     else       return tweet_urls     end   end 

so returns appropriate class. works, know wrong, not sure doing.

how work you

class user   has_many :feeds   has_many :twitters, through: :feeds, source: :feedable, source_type: 'twitter'   has_many :webpages, through: :feeds, source: :feedable, source_type: 'webpage'   has_many :pictures, through: :feeds, source: :feedable, source_type: 'picture' end  class feed   belongs_to :user   belongs_to :feedable, polymorphic: true end 

now feeds table need feedable_id , feedable_type associations work expected. e.g.

website.create name: "website", url: "http://www.example.com" user = user.create name: "user" feed = user.feeds.build feed.feedable = website.find_by_name("website") feed.save 

i don't have ton of experience sort of has_many through polymorphic conceptually should work you. in case not solve problem there ton of questions , articles if google polymorphic has_many through.