在polymorphic_path中使用块

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!