application_controller.rb

require "application_responder"

class ApplicationController < ActionController::Base

  # ...

  def self.acts_as_magical
    around_filter :magic_new,     :only => :new
    around_filter :magic_show,    :only => :show
    around_filter :magic_edit,    :only => :edit
    around_filter :magic_update,  :only => :update
    around_filter :magic_create,  :only => :create
    around_filter :magic_index,   :only => :index
    around_filter :magic_destroy, :only => :destroy
  end 
  
  # ...
  
  protected
  
  def magic_index
    instance_variable_set("@#{object_name.pluralize}", data_source)
    yield
  end 
  
  def magic_show
    instance_variable_set("@#{object_name}", data_source.find_by_id(params[:id]))
    yield
  end 
  
  def magic_new
    instance_variable_set("@#{object_name}", data_source.new)
    yield
  end 

  def magic_create
    instance_variable_set("@#{object_name}", data_source.create(params[object_name]))
    yield
    respond_with *lineage
  end 
  
  def magic_edit
    instance_variable_set("@#{object_name}", data_source.find_by_id(params[:id]))
    yield
  end 
  
  def magic_update
    instance_variable_set("@#{object_name}", data_source.find_by_id(params[:id]))
    instance_varialbe_get("@#{object_name}").update_attributes(params[object_name])
    yield
    respond_with *lineage
  end 
  
  def magic_destroy
    instance_variable_set("@#{object_name}", data_source.find_by_id(params[:id]))
    instance_varialbe_get("@#{object_name}").destroy
    yield
    respond_with *lineage
  end 

  def object
    instance_variable_get("@#{object_name}")
  end 
  
  def object_name
    self.class.name.split('::').last.sub(/Controller$/,'').singularize.underscore
  end 
  
end