## lib/expose.rb

module Padrino
  module Routing
    module ClassMethods
      def expose(sym,opts={})
        klass          = sym.to_s.classify.constantize
        find_by        = opts[:find_by] || :id
        default_params = "params[:id] || params[:#{sym.to_s}_id]"
        collector      = opts[:collect] ? opts[:collect] : "#{klass}.all"
        eval <<-EVAL
        helpers do
          def #{sym.to_s.pluralize}
            @#{sym.to_s.pluralize} ||= #{collector}
          end
          def #{sym.to_s}
            @#{sym.to_s} ||= if #{default_params}
              #{klass}.first(#{find_by} => #{default_params})
            elsif request.post?
              #{klass}.create(params[:#{sym.to_s}])
            elsif request.put?
              #{klass}.update_attributes(params[:#{sym.to_s}])
            else
              #{klass}.new
            end
          end
        end
        EVAL
      end
    end
  end
end

## Usage controllers/pages.rb

expose :page, :find_by => :slug, :collect => 'current_site.pages'

## Example RESTful controller in tandem with padrino responders

Admin.controllers :pages do

  before { current_site }
  expose :page, :collect => "current_site.pages", :find_by => :slug

  get :index do respond(pages) end
  get :new do respond(page)  end
  get :edit, :with => :id do respond(page)  end
  get :show, :with => :id do respond(page)  end

  post :create do
    page.save
    response = url(:pages, :index, :site_id => params[:site_id])
    respond(page,response)
  end

  put :update, :with => :id do
    page.update_attributes(params[:page])
    response = url(:pages, :index, :site_id => params[:site_id])
    respond(page,response)
  end

  delete :destroy, :with => :id do
    page.destroy ? flash[:notice] = 'Success!' : flash[:error] = 'Woops!'
    redirect(url(:pages, :index))
  end

end