ハズレ日記

はてブでotsuneさんやkazuhookuさんがPHPクオリティについて勘違いしていたので、一言申し上げたところ、参考にされた方がいたようで、もうちょっと補足します。

いくつか実装での「正しいメールアドレス」を調べてみました。

phpspot

function is_mail($text) {
    if (preg_match('/^[a-zA-Z0-9_\.\-]+?@[A-Za-z0-9_\.\-]+$/',$text)) {
        return TRUE;
    } else {
        return FALSE;
    }
}

PEAR::Mail_RFC822

    function isValidInetAddress($data, $strict = false)
    {
        $regex = $strict ? '/^([.0-9a-z_+-]+)@(([0-9a-z-]+¥.)+[0-9a-z]{2,})$/i' : '/^([*+!.&#$|¥'¥¥%¥/0-9a-z^_`{}=?‾:-]+)@(([0-9a-z-]+¥.)+[0-9a-z]{2,})$/i';
        if (preg_match($regex, trim($data), $matches)) {
            return array($matches[1], $matches[2]);
        } else {
            return false;
        }
    }

CakePHP

define('VALID_EMAIL', '/¥¥A(?:^([a-z0-9][a-z0-9_¥¥-¥¥.¥¥+]*)@([a-z0-9][a-z0-9¥¥.¥¥-]{0,63}¥¥.(com|org|net|biz|info|name|net|pro|aero|coop|museum|[a-z]{2,4}))$)¥¥z/i');

Ethna

    function checkMailAddress($mailaddress)
    {
        if (preg_match('/^([a-z0-9_]|\-|\.|\+)+@(([a-z0-9_]|\-)+\.)+[a-z]{2,6}$/i',
                       $mailaddress)) {
            return true;
        }
        return false;

symfony

  public function execute(&$value, &$error)
  {
    $strict = $this->getParameterHolder()->get('strict');
    if ($strict == true)
    {
      $re = '/^([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})$/i';
    }
    else
    {
      /* Cal Henderson: http://iamcal.com/publish/articles/php/parsing_email/pdf/
       * The long regular expression below is made by the following code
       * fragment:
       *
       *   $qtext = '[^\\x0d\\x22\\x5c\\x80-\\xff]';
       *   $dtext = '[^\\x0d\\x5b-\\x5d\\x80-\\xff]';
       *   $atom = '[^\\x00-\\x20\\x22\\x28\\x29\\x2c\\x2e\\x3a-\\x3c'
       *         . '\\x3e\\x40\\x5b-\\x5d\\x7f-\\xff]+';
       *   $quoted_pair = '\\x5c\\x00-\\x7f';
       *   $domain_literal = "\\x5b($dtext|$quoted_pair)*\\x5d";
       *   $quoted_string = "\\x22($qtext|$quoted_pair)*\\x22";
       *   $domain_ref = $atom;
       *   $sub_domain = "($domain_ref|$domain_literal)";
       *   $word = "($atom|$quoted_string)";
       *   $domain = "$sub_domain(\\x2e$sub_domain)*";
       *   $local_part = "$word(\\x2e$word)*";
       *   $addr_spec = "$local_part\\x40$domain";
       */

      $re = '/^([^\\x00-\\x20\\x22\\x28\\x29\\x2c\\x2e\\x3a-\\x3c\\x3e\\x40\\x5b-'
           .'\\x5d\\x7f-\\xff]+|\\x22([^\\x0d\\x22\\x5c\\x80-\\xff]|\\x5c\\x00-'
           .'\\x7f)*\\x22)(\\x2e([^\\x00-\\x20\\x22\\x28\\x29\\x2c\\x2e\\x3a-'
           .'\\x3c\\x3e\\x40\\x5b-\\x5d\\x7f-\\xff]+|\\x22([^\\x0d\\x22\\x5c\\x80'
           .'-\\xff]|\\x5c\\x00-\\x7f)*\\x22))*\\x40([^\\x00-\\x20\\x22\\x28\\x29'
           .'\\x2c\\x2e\\x3a-\\x3c\\x3e\\x40\\x5b-\\x5d\\x7f-\\xff]+|\\x5b([^'
           .'\\x0d\\x5b-\\x5d\\x80-\\xff]|\\x5c\\x00-\\x7f)*\\x5d)(\\x2e([^\\x00-'
           .'\\x20\\x22\\x28\\x29\\x2c\\x2e\\x3a-\\x3c\\x3e\\x40\\x5b-\\x5d\\x7f-'
           .'\\xff]+|\\x5b([^\\x0d\\x5b-\\x5d\\x80-\\xff]|\\x5c\\x00-\\x7f)*'
           .'\\x5d))*$/'
      ;
    }

    if (!preg_match($re, $value))
    {
      $error = $this->getParameterHolder()->get('email_error');
      return false;
    }

    $checkDomain = $this->getParameterHolder()->get('check_domain');
    if ($checkDomain && function_exists('checkdnsrr'))
    {
      $tokens = explode('@', $value);
      if (!checkdnsrr($tokens[1], 'MX') && !checkdnsrr($tokens[1], 'A'))
      {
        $error = $this->getParameterHolder()->get('email_error');

        return false;
      }
    }

    return true;
  }