Accepting any 10 digit number in a string as a phone number

validate_phone_number.rb

class XXX < ActiveRecord::Base

  before_validation :format_phone
  validates_presence_of :phone
  validates_length_of :phone, :is => 10

  attr_accessible :phone

  private
  def format_phone
    unless self.phone.nil?
      formatted_phone = self.phone.scan(/\d+/).join
      self.phone = formatted_phone
    end 
  end 

end