Ruby on Rails

Rails 2.1 already has quite good support for namespaced models, and Edge Rails seems to fix some bugs left. In practice, however, there are still some issues left.

I really wanted to get namespaces and models work nicely. So here's a patch that changes one convention and improves Rails support for namespaced models. I never done such thingie before, so pardon any mistakes I made, but I surely found this screencast very useful. The patch is against the latest development trunk (18th June 2008).

The convention for database table names of namespaced models currently is:

  module Animal; class Lion < ActiveRecord::Base; end; end;
  Animal::Lion  # ( database name --> )  lions

I changed this to:

  Animal::Lion  # -->  animal_lions

This, however, overlaps with the convention of nested classes:

  class Animal < ActiveRecord::Base; class Lion < ActiveRecord::Base; end; end;  
  Animal::Lion  # -->  animal_lions

In practice, this is not such a big problem, because we now at least "bigger" namespace we can use, and I guess you will have problems anyways if you have a module and class with exactly same name in your Ruby code. I also tried convention of using two ugly underscores (e.g. animal__lions) and also tried to stick with the old convention. After all the experimenting, the convention I chose seemed to work best. The greatest benefit, of course, is that we really get bigger namespace for our models. It also improves how we can handle fixtures.

Perhaps the correct solution would be to provide this new table naming convention as configurable option?

I did quite a lot of manual testing using various associations. I also tried STI and polymorphic inheritance. They seemed to work well. has_many :through had problems, but it probably is an another problem (ticket #323 may contain a patch).

Next, I needed to check out the ActiveRecord tests pass. Well, they did not, because I changed the database table naming convention. Not many changes though, but one line did not please my very much:

  assert_equal 'my_application_business_company_my_application_business_client_contacts', MyApplication::Business::Client::Contact.table_name,  'table_name for ActiveRecord model enclosed by another ActiveRecord model'

MyApplication::Business::Client::Contact is inner class of MyApplication::Business::Company, so according the new rules, it is correct, but err... ugly. The positive aspect is that it gave as unlikely conflicting table name and probably it does not happen too often.

ActiveRecord tests depend of fixtures, and of course, they weren't working after the changes made. I really wanted fixtures to work so that I can organize fixtures just like I would organize my model files. For instance: 'animal' folder would contain 'lions.yml' for fixtures. The final solution, while being somewhat hackish, would find lion fixtures both under animal/lions.yml or animal_lions.yml. First one will keep you more organized and the latter one is consistent with the database table names.

Ok, all the existing tests pass and cannot find anything major by testing with Rails code and console. But what about generators? We use them every day and without working generators we don't really have working namespaces. These generator should now work fine by supporting namespaces:

• model
• resource
• scaffold

For instance scaffolding an Animal::Lion should generate fully working controllers, views, routing, fixtures and test cases. The trickiest part was to improve routing, but now routes to namespaced resources should be namespaced as well. For instance:

  map.namespace :animal do |animal|
    animal.resources :lions
  end

I am still very much novice with my Rails abilities, and my code may still look more like Java than Ruby. Don't let this you down. Instead, please help me by testing the patch and by:

• improving the code
• writing some proper unit tests
• check out if I have done something really stupid (yes, it's possible, see the comments in the patch)
• giving those +1's :-)
• tell me what should I do next