Sophisticated route and url generation in Rails - ruby-on-rails

Question

I have a group model which has_many article model. And I want to use the following url pattern "{group_id}/{article_id}".
so I wrote these route codes:
resource :groups do
resource :articles
end
match ':group_id/:id(.:format)', :to => 'articles#show', :as => :article
match ':id', :to => 'groups#show', :as => :group
But rails fail to generate correct url for group records and article records. How can I replace the automatic generated article_path and group_path to match my routes?

Answer 1

You're running into problems because you aren't watching out for pluralization. When you define a singular resource route, Rails doesn't treat it as a collection where you would refer to each member with an id. You instead want a plural resources for both groups and articles:
resources :groups do
resources :articles
end
Generates the following routes:
group_articles GET /groups/:group_id/articles(.:format) {:action=>"index", :controller=>"articles"}
POST /groups/:group_id/articles(.:format) {:action=>"create", :controller=>"articles"}
new_group_article GET /groups/:group_id/articles/new(.:format) {:action=>"new", :controller=>"articles"}
edit_group_article GET /groups/:group_id/articles/:id/edit(.:format) {:action=>"edit", :controller=>"articles"}
group_article GET /groups/:group_id/articles/:id(.:format) {:action=>"show", :controller=>"articles"}
PUT /groups/:group_id/articles/:id(.:format) {:action=>"update", :controller=>"articles"}
DELETE /groups/:group_id/articles/:id(.:format) {:action=>"destroy", :controller=>"articles"}
groups GET /groups(.:format) {:action=>"index", :controller=>"groups"}
POST /groups(.:format) {:action=>"create", :controller=>"groups"}
new_group GET /groups/new(.:format) {:action=>"new", :controller=>"groups"}
edit_group GET /groups/:id/edit(.:format) {:action=>"edit", :controller=>"groups"}
group GET /groups/:id(.:format) {:action=>"show", :controller=>"groups"}
PUT /groups/:id(.:format) {:action=>"update", :controller=>"groups"}
DELETE /groups/:id(.:format) {:action=>"destroy", :controller=>"groups"}
If you want to leave off the groups and articles segments you can pass :path => '' to each of the resources definitions, but you are going to have to tread carefully because any request to http://example.com/1/2 will map to an article under groups and be uninformative to end users and bots alike.