email_validation.rb

## Email validation
#
# Submitter: Paul Bergeron - paul.d.bergeron@gmail.com
# Website:   pauldbergeron.com
# Github:    https://github.com/dinedal
# Location:  San Francisco - CA
#
# A few notes:
#
# Never use this in production. A real email validation method should actually
# make an attempt to resolve the hostname associated with email,
# as this is the only really 100% reliable way to ensure that a given email
# actually has a valid hostname.
#
# This does mean that `someone@com` would fail validation, but a real
# production service probably doesn't even want to attempt to send email to
# that address anyway.


class EmailValidator

  def validate(email)
    email = email.to_s.strip
    regex = /^                # START
(".*"                         # username with quotes so special chars match
|                             # OR
[a-zA-Z0-9.+]*)               # username no quotes
@                             # @
[a-zA-Z0-9.?]*                # hostname or TLD
$                             # END
/x
    if regex.match(email)
      true
    else
      false
    end
  end

end


email_validator = EmailValidator.new

File.open(ARGV.first).readlines.each do |line|
  next if line.strip.empty?
  puts email_validator.validate(line)
end