Call Me Back

Synopsis

Automatically provide dead-simple ActiveSupport callbacks to your instance methods.

Preface

This gem is a small extension of ActiveSupport available features. In fact, as referred at this this link, creating callbacks for custom methods induces modify your existent method code source. This gem just automates this task.

Why?

When I work in Ruby On Rails projects, I often use native callbacks, provided by ActiveSupport, such as before_save or after_create. But sometimes I want to use this kind of hook methods for my methods. Of course, there is a way to perform this, explained in the previous link. This gem just simplifies the way you can do this.

Installation

Just type:

gem install callmeback

Or add it to your gem file:

gem 'callmeback'

Usage

Basic

Add include Callmeback to your class:

class Example
  include Callmeback

  before :foo => :bar

  def initialize
    callmeback!
    @result = []
  end

  def foo
    @result << 'foo'
  end

  def bar
    @result << 'bar'
  end
end

example = Example.new
example.foo #=> ['bar','foo']

Because your methods must be redefined to perform custom callbacks, you need to call #callmeback! on initialization.

You can use before, after and around, as if you use the suggested method in the ActiveSupport::Callbacks documentation. To perform the around callbacks, define them like:

around :foo => :wrapped_foo

def wrapped_foo
  bar
  yield
  bar
end

ActiveRecord and Mongoid

You may want to use Callmeback on your ActiveRecord or Mongoid models. I recommend you not to redefine the initialize method. Instead please use the after_initialize callback. Here is an example using Mongoid:

class Example
  include Mongoid::Document
  include Callmeback

  after_initialize do
    callmeback!
  end
  ...

Array of callbacks

You can pass an array of callback method symbol:

before :foo => [:bar, :bar]
# => ['bar', 'bar', 'foo']

Blocks

You also can pass blocks:

before :foo do
  bar
end

after :foo do
  bar
end

around :foo do |&block|
  bar
  block.call
  bar
end

Combinations

You can combine them with methods:

before :foo => [:bar, :bar]
after :foo do
  bar
end

Array of binded methods

You can pass an array of the methods you want:

before [:foo, :bar] => [:other_method]

Regex

You can run a callback for every method that matches a given regex:

before /^fo.$/ => [:bar, :bar]

How is it work?

First, this gem module defines the class methods .before, .after, .around in your class. Then when you instanciate your class, the gem overrides your binded methods and wraps them to bind your custom callbacks.

Contributing to callmeback

Check out the latest master to make sure the feature hasn’t been implemented or the bug hasn’t been fixed yet.
Check out the issue tracker to make sure someone already hasn’t requested it and/or contributed it.
Fork the project.
Start a feature/bugfix branch.
Commit and push until you are happy with your contribution.
Make sure to add tests for it. This is important so I don’t break it in a future version unintentionally.
Please try not to mess with the Rakefile, version, or history. If you want to have your own version, or is otherwise necessary, that is fine, but please isolate to its own commit so I can cherry-pick around it.