Rails 4, subdomain routing

Trying to implement web service in rails through API sub-domain called “api”.
In my hosts file i added line: 127.0.0.1 api.localhost

In my routes.rb i set sub-domain, where i only need index action and few manually added restful routes, through following:

namespace :api, path: '', :constraints => {:subdomain => "api"} do
  resources :posts, only: :index do
    collection do
      get 'popular_by_day'
      get 'popular_by_week'
    end
  end
end

Also generated coresponding controller with: rails g controller api/posts

Test example:

class Api::PostsController < ApplicationController
  def index
@posts = 1
    respond_to do |format|
        format.json { render :json => @posts }
    end
  end
  def popular_by_day
end
  def popular_by_week
end
end
After rake routes i have following:
popular_by_day_api_posts GET /posts/popular_by_day(.:format)  api/posts#popular_by_day {:subdomain=>"api"}
popular_by_week_api_posts GET /posts/popular_by_week(.:format) api/posts#popular_by_week {:subdomain=>"api"}
                api_posts GET /posts(.:format)                 api/posts#index {:subdomain=>"api"}
Far as i know, link to [http://api.localhost:3000/posts](http://api.localhost:3000/posts) should work but i get routing error:
**No route matches [GET] "/posts"** (Same with /posts.json)

This isn’t how localhost works, at all.

If you need to set up a local subdomain for testing, you most likely will need to do things like modify your /etc/hosts table, set up local DNS resolvers, and the like. If you’re running on a mac, you can use pow, which makes all that dead-easy.

But you could use:
  http://api.127.0.0.1.xip.io:3000/posts

See http://xip.io/ for the details, but this will resolve to the IP address before the .xip.io and then api will be the subdomain.

-Rob

+++Rob. I didn’t know about xip.io, thanks!