Oha

Decouple the business logic from the delivery mechanismt by using this gem.

1. Define the use case.
2. Create the UseCase class.
3. Bind the UseCase's happy path (and the not so happy ones) to what the calling object should execute in each case.
4. Profit

Add this line to your application's Gemfile:

gem 'oha'

And then execute:

$ bundle

Or install it yourself as:

$ gem install oha

In the calling object:

SomeUseCase.call(params) do |use_case|
  use_case.bind(:success).to(redirect_to_user)
  use_case.bind(:data_invalid).to(render_new)
  use_case.bind(:another_error).to(do_something_different)
end

def redirect_to_user
  -> (payload) do
    redirect_to user_path(payload[:user])
  end
end

def render_new
  -> (_payload) do
    render :new
  end
end

def do_something_different
  -> (_payload) do
    # ...
  end
end

The Use Case:

class SomeUseCase
  include Oha

  def call(params)
    trigger(:data_invalid) if invalid_params?
    do_something
    trigger(:success, user: @user)
  rescue SomeError
    trigger(:another_error)
  end
  
  private
  
  def do_something
    @user = ...
    #...
  end
end

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec 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 tags, and push the .gem file to rubygems.org.

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

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

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