Is it possible to create sub-applications in Ruby on Rails 3 or something like slices from Merb?

Question

Does Rails 3 have anything akin to slices in Merb, or areas in Django where there is a layer of organization above the controller? I heard at some point that they may allow hosting one rails app within another but I can't find any information on that in the pre-release material. Any hints on how to do something like this?

Answer 1

You're right there doesn't seem to be a lot of official documentation on it yet. But yes, you can have application slices -- they're called engines in Rails. Actually they've been available in Rails since 2.3. Currently, you basically make a plugin that has a complete application structure and set up your routes in there to "mount" your app against a specific URL. In Rails 3, engines are basically first-class objects in the Rails stack. I believe they can still be plugins but you will also be able keep it away from your application in a separate gem and require it in your application much more easily. You should be able to find stuff pretty easily on teh Google, but here's an oft-linked but informative reference: https://gist.github.com/af7e572c2dc973add221