Peafowl

Where do I put my application's business logic? I don't like to write business logics in rails' models or controllers. Peafowl encapsulate your business logic as a peafowl.

Installation

Add peafowl to your Gemfile and bundle install:

gem 'peafowl'

Getting Started

In addition to Interactor gem features, Peafowl support input validation. It is recommended that read Interactor gem before using Peafowl.

Peafowl use ActiveModel to provide validation for inputs. Following example shows a simple login service in Peafowl:

class LoginService
  include Peafowl

  attribute :username, String
  attribute :password, String

  validates :username, presence: true
  validates :password, presence: true

  def call
    sample_username = 'misugi'.freeze
    sample_password = 'captain_tsubasa'.freeze

    add_error!('Username or Password is not valid!') unless username == sample_username && password == sample_password

    context[:user] = { username: sample_username }
  end
end

And now you can use your service:

result = LoginService.call(username: 'misugi', password: 'captain_tsubasa')

raise UnauthorizedException.new(result.errors) if result.failure?

current_user = result.user

Input Parameters

You should define your input parameters with attribute keyword:

attribute param_name, String

String is parameter type and Peafowl will cast the passed argument to specified type (by Virtus gem).

add_error and add_error! Methods

Peafowl services returns array of string as error messages. add_error and add_error! get a string or array of string as argument.

add_error method adds error(s) to error list and does not break service execution. After end of execution failure? method will return true (and success? will return false).

add_error('Your error message.') if condition

add_error! is same as add_error with the difference that add_error! will break the execution of call method.

Why Peafowl?

Every gem which has been compared in this article has some drawbacks. I like active_interaction but it isn't flexible and doesn't support composition. interactor is very simple one with a flexible structure but doesn't support input validation.

Here are some advantages of Peafowl:

• Input validation
• Composition
• Simple error handling
• Readability, simplicity & flexibility

Todo

• Output validation
• Input type validation
• Better error handling