Service objects, verb-first

service_objects_verb_first.rb

# Illustrate the usage of service objects named in the verb-first form.

# a test user
user = User.where(name: 'Oleg').first

SubscribeUserToList.call(user)
# => "Oleg was added to the mailing list."

UnsubscribeUserFromList.call(user)
# => "Oleg was removed from the mailing list."

SendGoodbyeEmail.call(user)
# => "Sent a goodbye email to Oleg."

RemoveUserComments.call(user)
# => "Removed comments by Oleg."

ArchiveInactiveUsers.call([user])
# => "Oleg was removed from the mailing list."
# => "Sent a goodbye email to Oleg."
# => "Removed comments by Oleg."

archive_inactive_users.rb

# app/services/archive_inactive_users.rb
class ArchiveInactiveUsers
  def self.call(users)
    users.each do |user|
      UnsubscribeUserFromList.call(user)
      SendGoodbyeEmail.call(user)
      RemoveUserComments.call(user)
    end
  end
end

remove_user_comments.rb

# app/services/remove_user_comments.rb
class RemoveUserComments
  def self.call(user)
    # user.comments.destroy_all
    puts "Removed comments by #{user.name}."
  end
end

send_goodbye_email.rb

# app/services/send_goodbye_email.rb
class SendGoodbyeEmail
  def self.call(user)
    # Notifier.goodbye(user).deliver
    puts "Sent a goodbye email to #{user.name}."
  end
end

subscribe_user_to_list.rb

# app/services/subscribe_user_to_list.rb
class SubscribeUserToList
  def self.call(user, list = MailingList.new)
    # list.add!(user.email)
    puts "#{user.name} was added to the #{list.name} list."
  end
end

unsubscribe_user_from_list.rb

# app/services/unsubscribe_user_from_list.rb
class UnsubscribeUserFromList
  def self.call(user, list = MailingList.new)
    # list.remove!(user.email)
    puts "#{user.name} was removed from the #{list.name} list."
  end
end