EmailFormatValidator

email_format_validator.rb

class EmailFormatValidator < ActiveModel::EachValidator
  def validate_each record, attribute, value
    begin
      email = Mail::Address.new value
      # We must check that value contains a domain and that value is an email address
      result = email.domain && email.address == value
      tree = email.__send__ :tree
      # We need to dig into treetop
      # A valid domain must have dot_atom_text elements size > 1
      # user@localhost is excluded
      # treetop must respond to domain
      # We exclude valid email values like <user@localhost.com>
      # Hence we use email.__send__(tree).domain
      result &&= (tree.domain.dot_atom_text.elements.size > 1)
    rescue Exception => e
      result = false
    end
    record.errors[attribute] << (options[:message] || "is invalid") unless result
  end
end