Not all requirements can be expressed in terms of polymorphic url
options so add a `route_for` method that allows calling another
direct route (or regular named route) which a set of arguments, e.g:
resources :buckets
direct :recordable do |recording|
route_for(:bucket, recording.bucket)
end
direct :threadable do |threadable|
route_for(:recordable, threadable.parent)
end
This maintains the context of the original caller, e.g.
threadable_path(threadable) # => /buckets/1
threadable_url(threadable) # => http://example.com/buckets/1
Since a `direct` url helper block is evaluated using `instance_exec`
then methods that are available in the instance context can be
accessed, e.g. the params object in a controller action or view.
This wasn't clear from the example so expand on that point and add
a test case for this situation.
Allow the use of `direct` to specify custom mappings for polymorphic_url, e.g:
resource :basket
direct(class: "Basket") { [:basket] }
This will then generate the following:
>> link_to "Basket", @basket
=> <a href="/basket">Basket</a>
More importantly it will generate the correct url when used with `form_for`.
Fixes#1769.
Allow the definition of custom url helpers that will be available
automatically wherever standard url helpers are available. The
current solution is to create helper methods in ApplicationHelper
or some other helper module and this isn't a great solution since
the url helper module can be called directly or included in another
class which doesn't include the normal helper modules.
Reference #22512.
