unknown wrote in post #1116591: > I think I might be a little confused but I cant really understand > exactly > when to separate code into a concern, and when to separate it into a > library. > > 1. What's the exact difference?
Concerns is a technique used to either share some behavior between models or to break down "chubby" models into smaller, more coherent pieces. Notice this is all about model objects. Library code on the other hand should be self contained, independent behaviors that can be use anywhere. > 2. Where are they available? Model Concerns: Any model object where you choose to include them. Notice that concerns "extend ActiveSupport::Concern" and therefore have that direct dependency. Controller Concerns: Similar to the model concerns except for controllers. Library: Should have no direct dependencies outside of itself (other than libraries a library directly depends upon. i.e Rails itself has many dependencies managed by RubyGems). You should (in theory) be able to include a library anywhere, even in apps that don't use Rails at all. Notice that many gems (libraries) are useful no matter what framework you use them with. You could have a Sinatra app and include the same gem as in a Rails app. There's no direct dependency there. > 3. What is their goal? what is the goal of putting code in a concern and > in > a library? This explains concerns pretty well I think: http://37signals.com/svn/posts/3372-put-chubby-models-on-a-diet-with-concerns -- Posted via http://www.ruby-forum.com/. -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/rubyonrails-talk/1d3e3a59a45b3d60db7966150cdee30c%40ruby-forum.com. For more options, visit https://groups.google.com/groups/opt_out.
