= event_machine With event machine, you can keep an eye on any action on your rails controller, say in your sns website, when user posts a blog, you need to notice all of his friends, but it's really urgly to do like this: BlogController: def create # new and save code notice_all_friends end end let's take another scenario, in your sns site, when one user makes friends with the other one, we should notice all friends of these two people, but how to? we'd beeter have an observer on the action, the code in the make_friends action block only concerns about building relationship between the two people, the observer then notice other people, and this is also what IoC(AOP) teach us. Usage: in your config/environment.rb: gem "event_machine", :version => ">=0.2.1" application_controller.rb: class ApplicationController < ActionController::Base include EventMachine end and the generate command : ~your_project_path> rails g event_machine create_favorite FavoriteController create then it will generate a event file which content like following: for_action FavoritesController, :create do before do # This will be called before FavoriteController#create end after do # This will be called after FavoriteController#create end end now you can add your code in the block and after block, enjoy. = to observe multiple actions to observe multiple actions, you should: for_actions [[FavoritesController, :create], [BlogsController,:create]] do before do # your code goes here end after do # your code goes here end end == Note on Patches/Pull Requests * Fork the project. * Make your feature addition or bug fix. * Add tests for it. This is important so I don't break it in a future version unintentionally. * Commit, do not mess with rakefile, version, or history. (if you want to have your own version, that is fine but bump version in a commit by itself I can ignore when I pull) * Send me a pull request. Bonus points for topic branches. == Copyright Copyright (c) 2010 tim.teng. See LICENSE for details.