Aop

Very thin AOP gem for Ruby.

Thin and fast framework for Aspect Oriented Programming in Ruby.

Installation

Add this line to your application's Gemfile:

gem 'aop'

And then execute:

$ bundle

Or install it yourself as:

$ gem install aop

Usage

Before advice

module Authentication
  Aop["BankAccount#transfer:before"].advice do |account, *args, &blk|
    can!(:transfer, account)
  end

  def self.can!(action, subject)
    # raises error if current user can't execute `action` on `subject`
  end
end

After advice

module Analytics
  Aop["User#sign_in:after"].advice do |target, *args, &blk|
    report("sign_in", user.id)
  end
end

Around advice

module Transactional
  Aop["BankAccount#transfer:around"].advice do |joint_point, account, *args, &blk|
    start_transaction
    joint_point.call
    finish_transaction
  end
end

Class methods

Use .method notation:

module Transactional
  Aop["BankAccount.transfer:around"].advice do |joint_point, klass, *args, &blk|
    start_transaction
    joint_point.call
    finish_transaction
  end
end

Multiple classes, methods and advices

Use , to use multiple classes, methods and advices:

module Analytics
  Aop["User,Admin#sign_in,.sign_up,#sign_out:before,:after"].advice do |target, *args, &blk|
    report("auth_action", user.id)
  end
end

Handling missed pointcuts

When pointcut is gone, for example when method or class gets renamed, it is a potential bug, because some code will not be run. This library tackles this problem by failing hard when pointcut can not be found.

Example:

Aop["Admin#sign_in:after"].advice do |target, *args, &blk|
  # .. do something ..
end

Then somebody renames Admin#sign_in to Admin#logout, and when you run the code you will get:

Aop::PointcutNotFound: Unable to find pointcut Admin#sign_in
    Reason: #<NameError: undefined method `sign_in' for class `Admin'>
    .. backtrace ..

Contributing

1. Fork it ( https://github.com/waterlink/aop/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request