Using slugs in polymorphic_path - ruby-on-rails

Question

Is there a way I can use parameters in a polymorphic_path, to pass in a slug?
For instance, I have the following routes
routes.rb
MyApp::Application.routes.draw do
match "movies/:slug" => 'movies#show', :as=>:movie
match "series/:slug" => 'series#show', :as=>:series
end
And I have the following models:
Movie.rb
class Movie < ActiveRecord::Base
has_many :cast_members, :as=>:media_item
end
Series.rb
class Series < ActiveRecord::Base
has_many :cast_members, :as=>:media_item
end
CastMember.rb
class CastMember < ActiveRecord::Base
belongs_to :media_item, :polymorphic=>true
end
This works great, and I can reference my movie from the cast member, and vice-versa, just like a normal has_many/belongs_to relationship.
I can also do this from within my cast_member view:
*cast_members/show.html.erb*
link_to (#cast_member.movie.title, movie_path(#cast_member.movie.slug))
which returns "movie/movie-title"
and I can do
*cast_members/show.html.erb*
link_to (#cast_member.movie.title, polymorphic_path(#cast_member.media_item))
but this returns "/movies/24"
I've tried passing a slug as an item to polymorphic_path in different ways, like
link_to (#cast_member.movie.title, polymorphic_path(#cast_member.media_item, #cast_member.media_item.slug))
link_to (#cast_member.movie.title, polymorphic_path(#cast_member.media_item, :slug=>#cast_member.media_item.slug))
link_to ([#cast_member.movie.title, polymorphic_path(#cast_member.media_item, #cast_member.media_item.slug]))
but these all return errors or the path with the id.
How can I make the polymorphic_path use the movie.slug instead of the id?

Answer 1

I switched over to using friendly_id to generate slugs. It magically handles all the slug<->id conversions magically in the background, and sosolves the issue.
I do think that rails should have a baked-in way to do this, the same way you can pass a slug into the default *_path methods.

Answer 2

I solved this by using Rails' built-in path helpers instead of polymorphic_path. I really wanted to use that method, since it required use of the model's ID, I couldn't.
In my app, I have a lot of models that are "slugable", so it made sense to include a #to_path method in the slugable mixin.
# app/models/concerns/slugable.rb
module Slugable
extend ActiveSupport::Concern
included do
validates :slug, presence: true, uniqueness: {case_sensitive: false}
end
def to_path
path_method = "#{ActiveModel::Naming.singular_route_key(self)}_path"
Rails.application.routes.url_helpers.send(path_method, slug)
end
def slug=(value)
self[:slug] = value.blank? ? nil : value.parameterize
end
end
then in the templates:
<%= link_to my_slugable_model.name, my_slugable_model.to_path %>
If you have nested resources in your routes, then you'll need to adjust the code for that resource.
something like this (untested):
def to path(my_has_many_model_instance)
class_path = self.class.to_s.underscore
has_many_class_path = my_has_many_model_instance.class.to_s.underscore
path_method = "#{self_path}_#{has_many_class_path}_path"
Rails.application.routes.url_helpers.send(path_method, slug, my_has_many_model)
end
Good luck!