Question

What is the logical difference between resource and resources methods

Here is some examples:

resource :orders, :only => [:index, :create, :show]

> rake routes
 orders POST       /orders(.:format)            orders#create
        GET        /orders(.:format)            orders#show


resources :orders, :only => [:index, :create, :show]

> rake routes
 orders GET        /orders(.:format)            orders#index
        POST       /orders(.:format)            orders#create
  order GET        /orders/:id(.:format)        orders#show


resource :orders

> rake routes
     orders POST       /orders(.:format)            orders#create
 new_orders GET        /orders/new(.:format)        orders#new
edit_orders GET        /orders/edit(.:format)       orders#edit
            GET        /orders(.:format)            orders#show
            PUT        /orders(.:format)            orders#update
            DELETE     /orders(.:format)            orders#destroy


resources :orders

> rake routes
     orders GET        /orders(.:format)            orders#index
            POST       /orders(.:format)            orders#create
  new_order GET        /orders/new(.:format)        orders#new
 edit_order GET        /orders/:id/edit(.:format)   orders#edit
      order GET        /orders/:id(.:format)        orders#show
            PUT        /orders/:id(.:format)        orders#update
            DELETE     /orders/:id(.:format)        orders#destroy

It looks like method resource does not create route for index, and helpers in some cases are different (new_order and new_orders). Why?

Answer 1

Actually you are right, resource should not create an index action, unless you ask for the index action explicitly, this way:

resource :orders, :only => [:index, :create, :show]

Helpers should differ too, but not that much as in your example, because the convention is to use a singular form with the resource method, and the plural with the resources

resources :orders
=> rake routes

     orders GET        /orders(.:format)            orders#index
            POST       /orders(.:format)            orders#create
  new_order GET        /orders/new(.:format)        orders#new
 edit_order GET        /orders/:id/edit(.:format)   orders#edit
      order GET        /orders/:id(.:format)        orders#show
            PUT        /orders/:id(.:format)        orders#update
            DELETE     /orders/:id(.:format)        orders#destroy

resource :order
=> rake routes
      order POST       /order(.:format)            orders#create
  new_order GET        /order/new(.:format)        orders#new
 edit_order GET        /order/:id/edit(.:format)   orders#edit
            GET        /order/:id(.:format)        orders#show
            PUT        /order/:id(.:format)        orders#update
            DELETE     /order/:id(.:format)        orders#destroy

And the logical difference is to declare you logically can’t have the plural for resource in your app, for example Admin or whatever