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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.


Let's take… a cat.

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!"

after_dinner :have_a_desert   # => refers to Cat#have_a_desert

def have_a_desert
  puts "Hell, yeah!"

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!


You're free to pass any number of arguments to #run_callback.

cat.run_hook :before_dinner, cat,

The callbacks should be ready for receiving parameters.

before_dinner :wash_pawns
before_dinner do |who, when|

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


The current gem requires

  • active_support 2.3.x

Anybody using it?

  • Hooks is already used in [], 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.

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Copyright © 2010, Nick Sutterer

Released under the MIT License.