我认为你最好使用PHP的内置过滤器-在这种特殊情况下:

当提供FILTER_VALIDATE_EMAIL参数时，它可以返回true或false。

我认为你最好使用PHP的内置过滤器-在这种特殊情况下:

当提供FILTER_VALIDATE_EMAIL参数时，它可以返回true或false。

在FILTER_VALIDATE_EMAIL中有一个更好的正则表达式，但任何正则表达式都可能给出糟糕的结果。

例如. .

// "not an email" is invalid so its false.
php > var_export(filter_var("not an email", FILTER_VALIDATE_EMAIL));
false
// "foo@a.com" looks like an email, so it passes even though its not real.
php > var_export(filter_var("foo@a.com", FILTER_VALIDATE_EMAIL));
'foo@a.com'
// "foo@gmail.com" passes, gmail is a valid email server,
//  but gmail require more than 3 letters for the address.
var_export(filter_var("foo@gmail.com", FILTER_VALIDATE_EMAIL));
'foo@gmail.com'

你可能会考虑使用像Real Email这样的API，它可以进行深入的邮箱检查，以检查电子邮件是否真实。

有点像…

$email = "foo@bar.com";
$api_key = ???;

$request_context = stream_context_create(array(
    'http' => array(
        'header'  => "Authorization: Bearer " . $api_key
    )
));

$result_json = file_get_contents("https://isitarealemail.com/api/email/validate?email=" . $email, false, $request_context);

if (json_decode($result_json, true)['status'] == "valid") {
    echo("email is valid");
} else if (json_decode($result_json, true)['status'] == "invalid") {
    echo("email is invalid");
} else {
  echo("email was unknown");
}

/(?![[:alnum:]]|@|-|_|\.)./

现在，如果你使用带有type=email的HTML5表单，那么你已经有80%的安全性了，因为浏览器引擎有它们自己的验证器。为了补充它，将这个正则表达式添加到你的preg_match_all()并对其求反:

if (!preg_match_all("/(?![[:alnum:]]|@|-|_|\.)./",$email)) { .. }

找到HTML5表单使用的正则表达式进行验证 https://regex101.com/r/mPEKmy/1

看完这里的答案后，我得出了以下结论:

public static function isValidEmail(string $email) : bool
{
    if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
        return false;
    }

    //Get host name from email and check if it is valid
    $email_host = array_slice(explode("@", $email), -1)[0];

    // Check if valid IP (v4 or v6). If it is we can't do a DNS lookup
    if (!filter_var($email_host,FILTER_VALIDATE_IP, [
        'flags' => FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE,
    ])) {
        //Add a dot to the end of the host name to make a fully qualified domain name
        // and get last array element because an escaped @ is allowed in the local part (RFC 5322)
        // Then convert to ascii (http://us.php.net/manual/en/function.idn-to-ascii.php)
        $email_host = idn_to_ascii($email_host.'.');

        //Check for MX pointers in DNS (if there are no MX pointers the domain cannot receive emails)
        if (!checkdnsrr($email_host, "MX")) {
            return false;
        }
    }

    return true;
}

使用以下代码:

// Variable to check
$email = "john.doe@example.com";

// Remove all illegal characters from email
$email = filter_var($email, FILTER_SANITIZE_EMAIL);


// Validate e-mail
if (filter_var($email, FILTER_VALIDATE_EMAIL)) {
  echo("Email is a valid email address");
}