class Interface::ApiController < ActionController::Base
   def all_article                       
     all_article = Article.all.map do |article|
       { :id => article.id,
         :title => article.title,
         :content => article.content,
         :created_at => article.created_at,
         :attachment => article.attachment,
       }           
     end                    
      render :json => { :success =>true, :result => all_article}
  end
end  

   namespace :interface do
     resources :api, :only => [] do
       collection do
         get :all_article
       end
     end
   end

http://域名/interface/api/all_article

或者：

http://localhost:端口号/interface/api/all_article