Sweeper outside?

Sometimes we modify some stuff without controllers (for example we publish some stuff via rake task ignited by cron). Unfortunately Rails does not handle it “out of the box”, so we need to do it by ourselfs.

BaseSweeper

Let’s create a base sweeper class where all the “magic” will happen:

class BaseSweeper < ActionController::Caching::Sweeper

  def after_save(data)
    expire_data(data)
  end

  def after_destroy(data)
    expire_data(data)
  end

  def expire_data
    @controller ||= ActionController::Base.new
  end

end

There’s nothing special about this code, except:

@controller ||= ActionController::Base.new

This line will emulate (if needed) controller outside of standard Rails flow. Thanks to this we can sweep stuff whenever we need. Example:

class NewsSweeper < BaseSweeper

  observe News

  def expire_data(data)
      super
      expire_fragment /news_#{data.id}/
  end

end

There’s one more thing to do. We need to add sweeper to observers in application.rb file (so our sweeper will react on any change in observed model):
application.rb:

    config.active_record.observers =
      "CommentObserver",
      "JakistamInnyObserver",
      # Sweepery
      "NewsSweeper"