resolve

Define custom polymorphic mappings of models to urls. This alters the behavior of `polymorphic_url` and consequently the behavior of `link_to` and `form_for` when passed a model instance, e.g:

resource :basket

resolve "Basket" do
  [:basket]
end

This will now generate “/basket” when a `Basket` instance is passed to `link_to` or `form_for` instead of the standard “/baskets/:id”.

NOTE: This custom behavior only applies to simple polymorphic urls where a single model instance is passed and not more complicated forms, e.g:

# config/routes.rb
resource :profile
namespace :admin do
  resources :users
end

resolve("User") { [:profile] }

# app/views/application/_menu.html.erb
link_to "Profile", @current_user
link_to "Profile", [:admin, @current_user]

The first `link_to` will generate “/profile” but the second will generate the standard polymorphic url of “/admin/users/1”.

You can pass options to a polymorphic mapping - the arity for the block needs to be two as the instance is passed as the first argument, e.g:

resolve "Basket", anchor: "items" do |basket, options|
  [:basket, options]
end

This generates the url “/basket#items” because when the last item in an array passed to `polymorphic_url` is a hash then it’s treated as options to the url helper that gets called.

NOTE: The `resolve` method can’t be used inside of a scope block such as `namespace` or `scope` and will raise an error if it detects that it is.