ActiveDuty

Service objects, based loosely on Interactor.

Design

Define the logic in run and call it with call:

Basic usage

class AuthenticateUser < ActiveDuty::Base
  def initialize(email, password)
    @email, @password = email, password 
  end

  def run
    if user = User.authenticate(@email, @password)
      context.user = user 
    else
      fail!
    end
  end
end

Usage:

service = AuthenticateUser.new("josh@example.com", password: "password")
service.call 
if service.success?
  # do something
else
  puts service.errors.inspect 
end 

Advanced usage

init_with

A DSL for initializing.

Ordered arguments

class AuthenticateUser < ActiveDuty::Base 
  init_with :username, :password 
end 

Is the equivalent of:

class AuthenticateUser < ActiveDuty::Base 
  attr_reader :username, :password 
  def initialize(username, password)
    @username, @password = username, password 
  end 
end 

Keyword arguments

class AuthenticateUser < ActiveDuty::Base 
  init_with uname: :username, pw: :password  
end 

Is the equivalent of:

class AuthenticateUser < ActiveDuty::Base 
  attr_reader :username, :password 
  def initialize(uname:, pw:)
    @username, @password = uname, pw 
  end 
end 

Defaults

class AuthenticateUser < ActiveDuty::Base 
  init_with :username, [:password, nil] 
end 

Is the equivalent of:

class AuthenticateUser < ActiveDuty::Base 
  attr_reader :username, :password 
  def initialize(username, password = nil)
    @username, @password = username, password 
  end 
end 

Keyword arguments

class AuthenticateUser < ActiveDuty::Base 
  init_with uname: [nil, :username], pw: ["good-password", :password]
end 

Is the equivalent of:

class AuthenticateUser < ActiveDuty::Base 
  attr_reader :username, :password 
  def initialize(uname: nil, pw: "good-password")
    @username, @password = uname, pw 
  end 
end 

Callbacks

Supports after_initialize, before_call, after_call. They use ActiveModel::Callbacks under the hood, so the API is familiar.

Context

An OpenStruct for a setting information during the runtime of your service object. Exposed via context.

Errors

Uses ActiveModel::Errors under the hood.

Rollbacks

If your call fails and you need to do some housekeeping, define a rollback:

class AuthenticateUser < ActiveDuty::Base
  def rollback 
    # do something 
  end
end

Or class-level:

class AuthenticateUser < ActiveDuty::Base
  rollback do 
    # do something 
  end 
end

Failing

Need to fail? Call fail!

Sequential calls

Want to run service after service?

class ServiceTwo < ActiveDuty::Base; end 
class ServiceThree < ActiveDuty::Base; end 
class ServiceOne < ActiveDuty::Base 
  boots ServiceTwo, ServiceThree
end 

They won't take arguments at this time.