Hooki

Add before and after callbacks to methods.

Installation

Install the gem and add it to the application's Gemfile by executing:

$ bundle add hooki

If bundler is not being used to manage dependencies, install the gem by executing:

$ gem install hooki

Usage

You can use Hooki in several ways to add before and after callbacks to methods.

Hooki provides callbacks for instance and singleton methods:

instance: before_method, after_method singleton: before_singleton_method, after_singleton_method

All the callbacks accept optional parameters only and except for filtering in which methods trigger the callbacks. only and except accepts a single symbol or array.

This is a basic example:

class Foo
  include Hooki

  before_method :log_before, only: :bar # or [:bar]
  after_method :log_after, expect: :bar # or [:bar]

  before_singleton_method :log_singleton_before, only: [:bar] # or :bar
  after_singleton_method :log_singleton_after, expect: [:bar] # or :bar

  def self.bar
    puts "singleton bar"
  end

  def self.baz
    puts "singleton baz"
  end

  def self.log_singleton_before(method_name)
    puts "-- log singleton before #{method_name}"
  end

  def self.log_singleton_after(method_name)
    puts "-- log singleton after #{method_name}"
  end

  def bar
    puts "bar"
  end

  def baz
    puts "baz"
  end

  private

  def log_before(method_name)
    puts "-- log before #{method_name}"
  end

  def log_after(method_name)
    puts "-- log after #{method_name}"
  end
end

The previous example doesn't seem too useful, Hooki unchains its potential when used on class inheritance or modules, for example:

module Logger
  include Hooki

  before_method :log

  private

  def log(method_name)
    puts "running #{method_name}"
  end
end

class Foo
  include Logger

  def bar
    puts "bar"
  end

  def baz
    puts "baz"
  end
end

There are more examples on test/examples.rb

Performance

Good, but how slow is it? Well, this is a lot of metaprograming, so it will be slower than the traditional approach.

There are two benchmarks in benchmarks/ folder.

The results on my machine are the following:

$ bundle exec ruby benchmarks/no_job.rb
Warming up --------------------------------------
                with    58.373k i/100ms
             without   377.367k i/100ms
Calculating -------------------------------------
                with    387.588k (±20.7%) i/s -      1.868M in   5.058400s
             without      3.624M (±19.7%) i/s -     17.359M in   5.025660s

Comparison:
             without:  3623753.6 i/s
                with:   387587.8 i/s - 9.35x  slower


$ bundle exec ruby benchmarks/with_job.rb
Warming up --------------------------------------
                with    11.220k i/100ms
             without    14.801k i/100ms
Calculating -------------------------------------
                with    112.751k (± 8.7%) i/s -    561.000k in   5.025158s
             without    143.033k (±11.0%) i/s -    710.448k in   5.052800s

Comparison:
             without:   143033.0 i/s
                with:   112751.4 i/s - 1.27x  slower

The "no job" benchmark is ~9 times slower, but it is doing nothing, it doesn't seem a realistic scenario. The "with job" benchmark is only a bit slower.

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake test to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and the created tag, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/ceritium/hooki. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.

License

The gem is available as open source under the terms of the MIT License.

Code of Conduct

Everyone interacting in the Hooki project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.