Hi people, I have this route: # config/routes.rb map.namespace :backshop, :path_prefix => '/:shop_id/admin' do |backshop| backshop.resources :items end And I want to use the form_for magic to reuse the same form on both: new and edit views: <% form_for [:backshop, @item] do |f| %> This used to works, and used to build a create url for the item or update url for the item depending on the status of the @item object. But this is not working on this case because the routes don't exists without the shop_id parameter, and I don't know how to say to the form_for something like this: <% form_for [:backshop, @item], :shop_id => @shop do |f| %> Because it tries to use the @item like the :shop_id parameter. Or like this <% form_for [:backshop, @shop, @item] do |f| %> Because it tries to build this url: backshop_shop_order_path I Know I can just to extract the form_for declaration from the partial and do different calls on depending if new or edit: <% form_for( @item, :url => backshop_items_path( @shop ) ) do |f| %> and <% form_for( @item, :url => backshop_item_path( @shop, @item ) ) do |f| %> But I just wanted don't do this because I have a bunch of models and is a few boring :) Thanks for any suggestion f.