# Refactoring complex phone validations

I have a complex phone validation that does the following:

1. First, check if either a home phone, mobile phone or work phone is provided (there will be 3 text fields in form and at least one type of phone number is required).

2. Strip out any characters from the phone number that is not a digit except 'x' and '+', since those represent extensions and are valid.

3. Make sure that the phones that were provided actually pass the phone number regex test.

And this is how I implemented the 3 steps above:

  VALID_PHONE_FORMAT = /\A(?:(?:\+?1\s*(?:[.-]\s*)?)?(?:$$\s*([2-9]1[02-9]|[2-9][02-8]1|[2-9][02-8][02-9])\s*$$|([2-9]1[02-9]|[2-9][02-8]1|[2-9][02-8][02-9]))\s*(?:[.-]\s*)?)?([2-9]1[02-9]|[2-9][02-9]1|[2-9][02-9]{2})\s*(?:[.-]\s*)?([0-9]{4})(?:\s*(?:#|x\.?|ext\.?|extension)\s*(\d+))?\z/

validate :phone_provided
before_validation :clean_phone_numbers
validates_format_of :phone_home, with: VALID_PHONE_FORMAT, if: :home_is_filled?
validates_format_of :phone_mobile, with: VALID_PHONE_FORMAT, if: :mobile_is_filled?
validates_format_of :phone_work, with: VALID_PHONE_FORMAT, if: :work_is_filled?
validates_format_of :phone_fax, with: VALID_PHONE_FORMAT, if: :fax_is_filled?

private

def clean_phone_numbers
if phone_home.present?
end
if phone_mobile.present?
end
if phone_work.present?
end
if phone_fax.present?
end
end

send("#{attr}_before_type_cast").gsub(/[^\d+!x]/,'')
end

def phone_provided
if phone_home.blank? && phone_mobile.blank? && phone_work.blank?
errors.add(:base, "Must provide a phone number")
end
end

def home_is_filled?
!phone_home.blank?
end

def mobile_is_filled?
!phone_mobile.blank?
end

def work_is_filled?
!phone_work.blank?
end

def fax_is_filled?
!phone_fax.blank?
end


I particularly don't like how I am calling 4 different methods in the if condition for validates_format_of. I would like to only use one method and be able to tell which attribute to call blank? on. How can I refactor this?

1. Characters other than digits, !, or x are stripped.
2. If any of the four types of phone numbers is provided, it must be valid.
3. At least one of { home, mobile, work } must be provided.

Requirement 3 is taken care of by validate :phone_provided, which is simple and fine.

The dissatisfaction comes from implementing Requirements 1 and 2.

The implementation of Requirement 1 can be simplified by making strip_bad_characters() tolerant of nil. You can also call #read_attribute_before_type_cast() to avoid interpolation.

def strip_bad_characters(attr)
input.gsub(/[^\d+!x]/, '') if input
end


Also, clean_phone_numbers() can use a loop:

def clean_phone_numbers
[:phone_home, :phone_mobile, :phone_work, :phone_fax].each do |attr|
end
end


The solution for Requirement 2 is simple: wrap the entire regular expression in \A( )?\Z to make it optional. Then, you can get rid of all the …_is_filled? helpers.

You could do something like, using a little array magic

def clean_phone_numbers
%w(phone_home phone_mobile phone_work phone_fax).each do |attribute|