PHP 的 filter_var FILTER_VALIDATE_EMAIL 真的有效吗？

Question

在阅读了各种帖子后，我决定不使用 REGEX 来检查电子邮件是否有效，而是简单地使用 PHP 内置的 filter_var 函数。它似乎工作正常，直到它开始告诉我一封电子邮件无效，因为我里面有一个号码。

即 [email protected] 有效，而 [电子邮件受保护] 没有。

我是否遗漏了某些内容，或者 filter_var($email, FILTER_VALIDATE_EMAIL) 真的非常无效？

Answer 1

PHP 5.3.3 过滤器代码中使用的正则表达式基于 Michael Rushton 的博客，内容为 电子邮件地址验证。它似乎确实适用于您提到的情况。

您还可以查看比较电子邮件地址验证正则表达式<中的一些选项/a> （当前 PHP 中使用的正则表达式是经过测试的其中之一）。

然后您可以选择您更喜欢的正则表达式，并将其用于调用 preg_match()。

或者，您可以采用正则表达式并替换文件 PHP/ext/filter/tical_filter.c 中的正则表达式，函数 php_filter_validate_email()，然后重建 PHP。

Answer 2

[email protected] 似乎工作正常：
http://codepad.org/5HDgMW5i

但我确实看到人们抱怨它有问题，即使是在 SO 上。它很可能确实存在问题，但正则表达式解决方案也会存在问题。电子邮件地址规范非常非常复杂（RFC XXXX）。

这就是为什么您应该依赖的验证电子邮件的唯一解决方案是向该地址发送电子邮件并要求采取行动（例如：如果是注册脚本，请他们单击验证链接）。

Answer 3

function isValidEmail($email, $checkDNS = false)
{

    $valid = (
            /* Preference for native version of function */
            function_exists('filter_var') and filter_var($email, FILTER_VALIDATE_EMAIL)
            ) || (
                /* The maximum length of an e-mail address is 320 octets, per RFC 2821. */
                strlen($email) <= 320
                /*
                 * The regex below is based on a regex by Michael Rushton.
                 * However, it is not identical. I changed it to only consider routeable
                 * addresses as valid. Michael's regex considers a@b a valid address
                 * which conflicts with section 2.3.5 of RFC 5321 which states that:
                 *
                 * Only resolvable, fully-qualified domain names (FQDNs) are permitted
                 * when domain names are used in SMTP. In other words, names that can
                 * be resolved to MX RRs or address (i.e., A or AAAA) RRs (as discussed
                 * in Section 5) are permitted, as are CNAME RRs whose targets can be
                 * resolved, in turn, to MX or address RRs. Local nicknames or
                 * unqualified names MUST NOT be used.
                 *
                 * This regex does not handle comments and folding whitespace. While
                 * this is technically valid in an email address, these parts aren't
                 * actually part of the address itself.
                 */
                and preg_match_all(
                    '/^(?!(?:(?:\\x22?\\x5C[\\x00-\\x7E]\\x22?)|(?:\\x22?[^\\x5C\\x22]\\x22?))'.
                    '{255,})(?!(?:(?:\\x22?\\x5C[\\x00-\\x7E]\\x22?)|(?:\\x22?[^\\x5C\\x22]\\x22?))'.
                    '{65,}@)(?:(?:[\\x21\\x23-\\x27\\x2A\\x2B\\x2D\\x2F-\\x39\\x3D\\x3F\\x5E-\\x7E]+)|'.
                    '(?:\\x22(?:[\\x01-\\x08\\x0B\\x0C\\x0E-\\x1F\\x21\\x23-\\x5B\\x5D-\\x7F]|(?:\\x5C[\\x00-\\x7F]))*\\x22))'.
                    '(?:\\.(?:(?:[\\x21\\x23-\\x27\\x2A\\x2B\\x2D\\x2F-\\x39\\x3D\\x3F\\x5E-\\x7E]+)|'.
                    '(?:\\x22(?:[\\x01-\\x08\\x0B\\x0C\\x0E-\\x1F\\x21\\x23-\\x5B\\x5D-\\x7F]|'.
                    '(?:\\x5C[\\x00-\\x7F]))*\\x22)))*@(?:(?:(?!.*[^.]{64,})'.
                    '(?:(?:(?:xn--)?[a-z0-9]+(?:-+[a-z0-9]+)*\\.){1,126})'.'{1,}'.
                    '(?:(?:[a-z][a-z0-9]*)|(?:(?:xn--)[a-z0-9]+))(?:-+[a-z0-9]+)*)|'.
                    '(?:\\[(?:(?:IPv6:(?:(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){7})|'.
                    '(?:(?!(?:.*[a-f0-9][:\\]]){7,})(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,5})?::'.
                    '(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,5})?)))|'.
                    '(?:(?:IPv6:(?:(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){5}:)|'.
                    '(?:(?!(?:.*[a-f0-9]:){5,})'.'(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,3})?::'.
                    '(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,3}:)?)))?(?:(?:25[0-5])|'.
                    '(?:2[0-4][0-9])|(?:1[0-9]{2})|(?:[1-9]?[0-9]))(?:\\.(?:(?:25[0-5])|'.
                    '(?:2[0-4][0-9])|(?:1[0-9]{2})|(?:[1-9]?[0-9]))){3}))\\]))$/iD',
                    $email)
            );

    if( $valid )
    {
        if( $checkDNS && ($domain = end(explode('@',$email, 2))) )
        {
            /*
            Note:
            Adding the dot enforces the root.
            The dot is sometimes necessary if you are searching for a fully qualified domain
            which has the same name as a host on your local domain.
            Of course the dot does not alter results that were OK anyway.
            */
            return checkdnsrr($domain . '.', 'MX');
        }
        return true;
    }
    return false;
}


//-----------------------------------------------------------------

    var_dump(isValidEmail('[email protected]', true));
    // bool(true)

Answer 4

该过滤器最近已进行了改造。
http://codepad.org/Lz5m2S2N - 看来在键盘使用的版本中您的大小写已正确过滤

您可以另请参阅 http://bugs.php.net/49576 和 http://svn.php.net/viewvc/php/php-src /trunk/ext/filter/tical_filters.c 。正则表达式非常可怕。