Rails 3.1 How do I create an API route for "me" that points to the user resource

Question

I have a set of API routes in rails as follows

namespace "api" do
   namespace "v1" do
     resources :users do
       resources :posts
       resources :likes
       ...
     end
   end
end

So far, so good. I can GET /api/v1/users/fred_flintstone and retrieve all of the information for that user.

What I would like to do now is add the concept of "me" (ala facebook) such that if the user is authenticated (fred_flintstone), I can also do the following

GET /api/v1/me

GET /api/v1/me/posts

...

I require both sets of routes. So I want to achieve the same results either using GET /api/v1/me/posts OR GET /api/v1/users/fred_flintstone/posts.

I've been through the route tutorial and have googled so a pointer would be as much appreciated as a direct answer.

EDIT:

What I've done that has worked is pretty hacky. I've created a second set of entries in the routes table using a scope:

scope "/api/v1/me", :defaults => {:format => 'json'}, :as => 'me' do
  resources :posts, :controller => 'api/v1/users/posts'
  resources :likes, :controller => 'api/v1/users/likes'
  ...
end

And then I added a set_user method that tests for the presence of params[:user_id]. I'm really looking for a way to DRY this up.

Answer 1

What about leaving the routes the way they are in your post, and just solving this inside the controller?

Heres a before_filter that you could apply to all of the routes you have which pull a User from a :user_id.

# Set the @user variable from the current url; 
# Either by looking up params[:user_id] or
# by assigning current_user if params[:user_id] = 'me'
def user_from_user_id
  if params[:user_id] == 'me' && current_user
    @user = current_user
  else
    @user = User.find_by_user_id params[:user_id]
  end

  raise ActiveRecord::RecordNotFound unless @user
end

Then in your controller functions you can just use the @user variable without having to worry about whether the user passed a user_id, or me.

Hope that helps! :)

EDIT:

Lemme take another shot, given your comments.

How about a function that lists all the resources you wish to access via both the standard routes and the /me route. Then you can just use the function in both the namespaces you require.

routes.rb

# Resources for users, and for "/me/resource"
def user_resources
  resources :posts
  resources :likes
  ...
end

namespace 'api' do
   namespace 'v1' do
     resources :users do
       user_resources
     end
   end
end

scope '/api/v1/:user_id', :constraints => { :user_id => 'me' },
                          :defaults => {:format => 'json'}, :as => 'me' do
  user_resources
end

# We're still missing the plain "/me" route, for getting
# and updating, so hand code those in
match '/api/v1/:id' => 'users#show', :via => :get,
                                     :constraints => { :id => 'me' }                
match '/api/v1/:id' => 'users#update', :via => :put,
                                       :constraints => { :id => 'me' }