Pretty (dated) RESTful URLs in Rails

Question

I'd like my website to have URLs looking like this:

example.com/2010/02/my-first-post

I have my Post model with slug field ('my-first-post') and published_on field (from which we will deduct the year and month parts in the url).

I want my Post model to be RESTful, so things like url_for(@post) work like they should, ie: it should generate the aforementioned url.

Is there a way to do this? I know you need to override to_param and have map.resources :posts with :requirements option set, but I cannot get it all to work.

---

I have it almost done, I'm 90% there. Using resource_hacks plugin I can achieve this:

map.resources :posts, :member_path => '/:year/:month/:slug',
  :member_path_requirements => {:year => /[\d]{4}/, :month => /[\d]{2}/, :slug => /[a-z0-9\-]+/}

rake routes
(...)
post GET    /:year/:month/:slug(.:format)      {:controller=>"posts", :action=>"show"}

and in the view:

<%= link_to 'post', post_path(:slug => @post.slug, :year => '2010', :month => '02') %>

generates proper example.com/2010/02/my-first-post link.

I would like this to work too:

<%= link_to 'post', post_path(@post) %>

But it needs overriding the to_param method in the model. Should be fairly easy, except for the fact, that to_param must return String, not Hash as I'd like it.

class Post < ActiveRecord::Base
  def to_param
   {:slug => 'my-first-post', :year => '2010', :month => '02'}
  end
end

Results in can't convert Hash into String error.

This seems to be ignored:

def to_param
  '2010/02/my-first-post'
end

as it results in error: post_url failed to generate from {:action=>"show", :year=>#<Post id: 1, title: (...) (it wrongly assigns @post object to the :year key). I'm kind of clueless at how to hack it.

Answer 1

Pretty URLs for Rails 3.x and Rails 2.x without the need for any external plugin, but with a little hack, unfortunately.

routes.rb

map.resources :posts, :except => [:show]
map.post '/:year/:month/:slug', :controller => :posts, :action => :show, :year => /\d{4}/, :month => /\d{2}/, :slug => /[a-z0-9\-]+/

application_controller.rb

def default_url_options(options = {})
  # resource hack so that url_for(@post) works like it should
  if options[:controller] == 'posts' && options[:action] == 'show'
    options[:year] = @post.year
    options[:month] = @post.month
  end
  options
end

post.rb

def to_param # optional
  slug
end

def year
  published_on.year
end

def month
  published_on.strftime('%m')
end

view

<%= link_to 'post', @post %>

Note, for Rails 3.x you might want to use this route definition:

resources :posts
match '/:year/:month/:slug', :to => "posts#show", :as => :post, :year => /\d{4}/, :month => /\d{2}/, :slug => /[a-z0-9\-]+/

Is there any badge for answering your own question? ;)

Btw: the routing_test file is a good place to see what you can do with Rails routing.

Update: Using default_url_options is a dead end. The posted solution works only when there is @post variable defined in the controller. If there is, for example, @posts variable with Array of posts, we are out of luck (becase default_url_options doesn't have access to view variables, like p in @posts.each do |p|.

So this is still an open problem. Somebody help?