Generic hooks with callbacks for Ruby.
Hooks lets you define hooks declaratively in your ruby class. You can add callbacks to your hook, which will be run as soon as you run the hook!
It's almost like ActiveSupport::Callbacks but 76,6% less complex. Instead, it is not more than 60 lines of code, one method compilation, no method_missing and no magic.
Also, you may pass additional arguments to your callbacks when invoking a hook.
Let's take… a cat.
require 'hooks' class Cat include Hooks define_hook :after_dinner
Now you can add callbacks to your hook declaratively in your class.
after_dinner do puts "Ice cream!" end after_dinner :have_a_desert # => refers to Cat#have_a_desert def have_a_desert puts "Hell, yeah!" end
Running the callbacks happens on instances. It will run the block and #have_a_desert from above.
cat.run_hook :after_dinner # => Ice cream! Hell, yeah!
Hooks are inherited, here's a complete example to put it all together.
class Garfield < Cat after_dinner :want_some_more def want_some_more puts "Is that all?" end end Garfield.new.run_hook :after_dinner # => Ice cream! Hell, yeah! Is that all?
Note how the callbacks are invoked in the order they were inherited.
Options for Callbacks
You're free to pass any number of arguments to #run_callback, those will be passed to the callbacks.
cat.run_hook :before_dinner, cat, Time.now
The callbacks should be ready for receiving parameters.
before_dinner :wash_pawns before_dinner do |who, when| ... end def wash_pawns(who, when)
Not sure why a cat should have ice cream for dinner. Beside that, I was tempted naming this gem hooker.
gem install hooks
Anybody using it?
Hooks is already used in [Apotomo:github.com/apotonick/apotomo], a hot widget framework for Rails. Look at lib/apotomo/widget.rb for examples and into lib/apotomo/tree_node.rb to learn how modules-driven code might benefit from hooks.
Copyright © 2010, Nick Sutterer
Released under the MIT License.