Upcase Refactoring Trail

Extract Class

Refactoring exercise using the Extract Class refactoring for the Upcase Refactoring Trail.

Extract Class

You have one class doing work that should be done by two. Create a new class and move the relevant fields and methods from the old class into the new class. -- Martin Fowler

Before

# survey_inviter.rb

class SurveyInviter
  EMAIL_REGEX = /\A([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})\z/

  def initialize(attributes = {})
    @survey = attributes[:survey]
    @message = attributes[:message] || ''
    @recipients = attributes[:recipients] || ''
    @sender = attributes[:sender]
  end

  attr_reader :message, :recipients, :survey

  def valid?
    valid_message? && valid_recipients?
  end

  def deliver
    recipient_list.each do |email|
      invitation = Invitation.create(
        survey: @survey,
        sender: @sender,
        recipient_email: email,
        status: 'pending'
      )
      Mailer.invitation_notification(invitation, @message)
    end
  end

  def invalid_recipients
    @invalid_recipients ||= recipient_list.map do |item|
      unless item.match(EMAIL_REGEX)
        item
      end
    end.compact
  end

  private

  def valid_message?
    @message.present?
  end

  def valid_recipients?
    invalid_recipients.empty?
  end

  def recipient_list
    @recipient_list ||= @recipients.gsub(/\s+/, '').split(/[\n,;]+/)
  end
end

After

# survey_inviter.rb

class SurveyInviter
  def initialize(attributes = {})
    @survey     = attributes[:survey]
    @message    = attributes[:message] || ''
    @recipients = EmailParser.email_list_for attributes[:recipients]
    @sender     = attributes[:sender]
  end

  attr_reader :message, :recipients, :survey

  def valid?
    Validator.valid? message: message, recipients: recipients
  end

  def deliver
    recipients.each do |email|
      invitation = Invitation.create(
        survey: @survey,
        sender: @sender,
        recipient_email: email,
        status: 'pending'
      )
      Mailer.invitation_notification(invitation, @message)
    end
  end
end

# email_parser.rb

class EmailParser
  WHITESPACE = /\s+/
  DELIMITERS = /[\n,;]+/

  def self.email_list_for(recipients)
    new(recipients).email_list
  end

  def initialize(recipients)
    @recipients = recipients || ''
  end

  def email_list
    @email_list ||= parse_recipients
  end

  private

  def parse_recipients
    @recipients.gsub(WHITESPACE, '').split(DELIMITERS)
  end
end

# validator.rb

class Validator
  EMAIL_REGEX = /\A([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})\z/

  def self.valid?(message:, recipients:)
    new(message, recipients).valid?
  end

  def initialize(message, recipients)
    @message    = message
    @recipients = recipients
  end

  def valid?
    valid_message? && valid_recipients?
  end

  private

  def valid_message?
    @message.present?
  end

  def valid_recipients?
    invalid_emails.empty?
  end

  def invalid_emails
    @invalid_emails ||= @recipients.reject(&valid_emails)
  end

  def valid_emails
    proc { |item| item if item.match(EMAIL_REGEX) }
  end
end