Gourmet

Service Objects for Rails, useful for extracting business logic out of your controller actions. Credit goes to Philippe Creux for his original description of 'Gourmet Service Objects' in this blog post.

Installation

Add this line to your application's Gemfile:

gem 'gourmet'

And then execute:

$ bundle

Or install it yourself as:

$ gem install gourmet

Usage

Services are defined by subclassing Gourmet::Service and implementing a #call method. That's it! Service are an extremely thin wrapper over plain old Ruby objects, which make them easy to reason about and test in isolation. For example:

# app/services/create_and_track_signup.rb
class CreateAndTrackSignup < Gourmet::Service
  def call(name, email)
    User.create!(name: name, email: email)
    UserMailer.welcome_message(email).deliver
    mixpanel.track(email, 'signed up')
  end
end

# app/controllers/users_controller.rb
def create
  CreateAndTrackSignup.call(params[:name], params[:email])
  redirect_to dashboard_path
end

Handling complex return values

Gourmet ships with a built-in helper class Gourmet::Result for handling actions that may or may not succeed. Result has two subclasses Success and Failure (similar to Scala's Option pattern, or the Possibly gem in Ruby), which are instantiated using helper methods of the same name. Result objects implement #success? and #failure? query methods, and can also act as a wrapper for some value. To demonstrate:

class DoWork < Gourmet::Service
  def call(magic_number)
    if magic_number == 7
      Success(magic_number)
    else
      Failure()
    end
  end
end

result = DoWork.call(7)
result.success? # => true
result.value    # => 7

result = DoWork.call(2)
result.failure? # => true

Note that the use of the Result class and methods is completely optional - you're free to substitute your own mechanism for handling complex results, or forego it entirely.

Contributing

1. Fork it ( http://github.com/andrewberls/gourmet/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 new Pull Request