È possibile guardare il sorgente qui: https://github.com/rails/rails/blob/master/actionpack/lib/action_dispatch/routing/polymorphic_routes.rb
Quando redirect_to prende un modello, si filtra attraverso un paio di metodi per ottenere il percorso chiamando il metodo polymorphic_url. L'API per questo metodo [1] è in realtà un sacco di dettagli, copiato dai commenti qui:
# Constructs a call to a named RESTful route for the given record and returns the
# resulting URL string. For example:
#
# # calls post_url(post)
# polymorphic_url(post) # => "http://example.com/posts/1"
# polymorphic_url([blog, post]) # => "http://example.com/blogs/1/posts/1"
# polymorphic_url([:admin, blog, post]) # => "http://example.com/admin/blogs/1/posts/1"
# polymorphic_url([user, :blog, post]) # => "http://example.com/users/1/blog/posts/1"
# polymorphic_url(Comment) # => "http://example.com/comments"
#
# ==== Options
#
# * <tt>:action</tt> - Specifies the action prefix for the named route:
# <tt>:new</tt> or <tt>:edit</tt>. Default is no prefix.
# * <tt>:routing_type</tt> - Allowed values are <tt>:path</tt> or <tt>:url</tt>.
# Default is <tt>:url</tt>.
#
# ==== Examples
#
# # an Article record
# polymorphic_url(record) # same as article_url(record)
#
# # a Comment record
# polymorphic_url(record) # same as comment_url(record)
#
# # it recognizes new records and maps to the collection
# record = Comment.new
# polymorphic_url(record) # same as comments_url()
#
# # the class of a record will also map to the collection
# polymorphic_url(Comment) # same as comments_url()
In sostanza, la risposta alla tua domanda è che si chiama (equivalente) il metodo model_path (@model) per il modello.
[1] http://apidock.com/rails/ActionController/PolymorphicRoutes/polymorphic_url
fonte
2011-08-20 11:28:52