PHP에서 이메일 주소를 확인하는 방법

PHP에서 이메일 주소를 확인하는 방법

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이메일 주소를 확인하는이 기능이 있습니다.

function validateEMAIL($EMAIL) {
    $v = "/[a-zA-Z0-9_-.+]+@[a-zA-Z0-9-]+.[a-zA-Z]+/";

    return (bool)preg_match($v, $EMAIL);
}

이메일 주소가 유효한지 확인해도됩니까?

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이메일 주소가 올바른지 여부를 확인하는 가장 쉽고 안전한 방법은 다음 filter_var()기능 을 사용하는 것입니다.

if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
    // invalid emailaddress
}

또한 도메인이 MX레코드를 정의하는지 확인할 수 있습니다 .

if (!checkdnsrr($domain, 'MX')) {
    // domain is not valid
}

그러나 이것은 여전히 ​​메일의 존재를 보장하지 않습니다. 이를 확인하는 유일한 방법은 확인 메일을 보내는 것입니다.

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이제 빠른 답변을 얻었으므로 빠른 답변을 배우고 사용하고 계속 진행하려는 경우 이메일 주소 확인에 대해 자유롭게 읽으십시오. 유감 없음.

정규식을 사용하여 이메일 주소를 확인하는 것은 "불가능한"작업입니다. 나는 당신이 만든 정규식이 쓸모 없다고 말하기까지합니다. emailaddresses 및 잘못된 emailaddresses를 잡기 위해 정규식을 작성하는 3 가지 rfc가 있으며 동시에 잘못된 긍정이 없으면 필사자가 할 수없는 일입니다. PHP 함수에서 사용하는 정규식 테스트 (실패 및 성공)를 보려면이 목록 을 확인하십시오 filter_var().

내장 PHP 기능, 이메일 클라이언트 또는 서버조차도 제대로 작동하지 않습니다. 여전히 대부분의 경우 filter_var최선의 선택입니다.

이메일 주소의 유효성을 검사하기 위해 PHP가 현재 사용하는 정규식 패턴을 알고 싶다면 PHP 소스를 참조하십시오 .

이메일 주소에 대해 더 자세히 알고 싶다면 사양을 읽기 시작하는 것이 좋습니다. 그러나 모든 것이 쉽게 읽을 수는 없다고 경고해야합니다.

• rfc5322
• rfc5321
• rfc3696
• rfc6531 (유니 코드 문자를 허용하지만 많은 클라이언트 / 서버에서는이를 허용하지 않음)

참고 filter_var()로 이미 PHP 5.2으로 만 사용할 수 적혀있다. 이전 버전의 PHP에서 작동하려면 PHP에서 사용되는 정규식을 사용할 수 있습니다.

<?php

$pattern = '/^(?!(?:(?:\\x22?\\x5C[\\x00-\\x7E]\\x22?)|(?:\\x22?[^\\x5C\\x22]\\x22?)){255,})(?!(?:(?:\\x22?\\x5C[\\x00-\\x7E]\\x22?)|(?:\\x22?[^\\x5C\\x22]\\x22?)){65,}@)(?:(?:[\\x21\\x23-\\x27\\x2A\\x2B\\x2D\\x2F-\\x39\\x3D\\x3F\\x5E-\\x7E]+)|(?:\\x22(?:[\\x01-\\x08\\x0B\\x0C\\x0E-\\x1F\\x21\\x23-\\x5B\\x5D-\\x7F]|(?:\\x5C[\\x00-\\x7F]))*\\x22))(?:\\.(?:(?:[\\x21\\x23-\\x27\\x2A\\x2B\\x2D\\x2F-\\x39\\x3D\\x3F\\x5E-\\x7E]+)|(?:\\x22(?:[\\x01-\\x08\\x0B\\x0C\\x0E-\\x1F\\x21\\x23-\\x5B\\x5D-\\x7F]|(?:\\x5C[\\x00-\\x7F]))*\\x22)))*@(?:(?:(?!.*[^.]{64,})(?:(?:(?:xn--)?[a-z0-9]+(?:-+[a-z0-9]+)*\\.){1,126}){1,}(?:(?:[a-z][a-z0-9]*)|(?:(?:xn--)[a-z0-9]+))(?:-+[a-z0-9]+)*)|(?:\\[(?:(?:IPv6:(?:(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){7})|(?:(?!(?:.*[a-f0-9][:\\]]){7,})(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,5})?::(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,5})?)))|(?:(?:IPv6:(?:(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){5}:)|(?:(?!(?:.*[a-f0-9]:){5,})(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,3})?::(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,3}:)?)))?(?:(?:25[0-5])|(?:2[0-4][0-9])|(?:1[0-9]{2})|(?:[1-9]?[0-9]))(?:\\.(?:(?:25[0-5])|(?:2[0-4][0-9])|(?:1[0-9]{2})|(?:[1-9]?[0-9]))){3}))\\]))$/iD';

$emailaddress = 'test@gmail.com';

if (preg_match($pattern, $emailaddress) === 1) {
    // emailaddress is valid
}

PS 위에서 사용한 정규식 패턴에 대한 참고 사항 (PHP 소스에서). Michael Rushton 의 저작권이있는 것 같습니다 . 명시된 바와 같이 : "이 코드를 자유롭게 사용하고 재배포하십시오. 그러나이 저작권 고지 사항을 유지하십시오."

---

이를 위해 filter_var 를 사용할 수 있습니다 .

<?php
   function validateEmail($email) {
      return filter_var($email, FILTER_VALIDATE_EMAIL);
   }
?>

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In my experience, regex solutions have too many false positives and filter_var() solutions have false negatives (especially with all of the newer TLDs).

Instead, it's better to make sure the address has all of the required parts of an email address (user, "@" symbol, and domain), then verify that the domain itself exists.

There is no way to determine (server side) if an email user exists for an external domain.

This is a method I created in a Utility class:

public static function validateEmail($email)
{
    // SET INITIAL RETURN VARIABLES

        $emailIsValid = FALSE;

    // MAKE SURE AN EMPTY STRING WASN'T PASSED

        if (!empty($email))
        {
            // GET EMAIL PARTS

                $domain = ltrim(stristr($email, '@'), '@') . '.';
                $user   = stristr($email, '@', TRUE);

            // VALIDATE EMAIL ADDRESS

                if
                (
                    !empty($user) &&
                    !empty($domain) &&
                    checkdnsrr($domain)
                )
                {$emailIsValid = TRUE;}
        }

    // RETURN RESULT

        return $emailIsValid;
}

---

I think you might be better off using PHP's inbuilt filters - in this particular case:

It can return a true or false when supplied with the FILTER_VALIDATE_EMAIL param.

---

This will not only validate your email, but also sanitize it for unexpected characters:

$email  = $_POST['email'];
$emailB = filter_var($email, FILTER_SANITIZE_EMAIL);

if (filter_var($emailB, FILTER_VALIDATE_EMAIL) === false ||
    $emailB != $email
) {
    echo "This email adress isn't valid!";
    exit(0);
}

---

Answered this in 'top question' about emails verification https://stackoverflow.com/a/41129750/1848217

For me the right way for checking emails is:

1. Check that symbol @ exists, and before and after it there are some non-@ symbols: /^[^@]+@[^@]+$/
2. Try to send an email to this address with some "activation code".
3. When the user "activated" his email address, we will see that all is right.

Of course, you can show some warning or tooltip in front-end when user typed "strange" email to help him to avoid common mistakes, like no dot in domain part or spaces in name without quoting and so on. But you must accept the address "hello@world" if user really want it.

Also, you must remember that email address standard was and can evolute, so you can't just type some "standard-valid" regexp once and for all times. And you must remember that some concrete internet servers can fail some details of common standard and in fact work with own "modified standard".

So, just check @, hint user on frontend and send verification emails on given address.

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If you're just looking for an actual regex that allows for various dots, underscores and dashes, it as follows: [a-zA-z0-9.-]+\@[a-zA-z0-9.-]+.[a-zA-Z]+. That will allow a fairly stupid looking email like tom_anderson.1-neo@my-mail_matrix.com to be validated.

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

Nowadays, if you use a HTML5 form with type=email then you're already by 80% safe since browser engines have their own validator. To complement it, add this regex to your preg_match_all() and negate it:

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

Find the regex used by HTML5 forms for validation
https://regex101.com/r/mPEKmy/1

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If you want to check if provided domain from email address is valid, use something like:

/*
* Check for valid MX record for given email domain
*/
if(!function_exists('check_email_domain')){
    function check_email_domain($email) {
        //Get host name from email and check if it is valid
        $email_host = explode("@", $email);     
        //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)
        $host = end($email_host) . "."; 
        //Convert to ascii (http://us.php.net/manual/en/function.idn-to-ascii.php)
        return checkdnsrr(idn_to_ascii($host), "MX"); //(bool)       
    }
}

This is handy way to filter a lot of invalid email addresses, along with standart email validation, because valid email format does not mean valid email.

Note that idn_to_ascii() (or his sister function idn_to_utf8()) function may not be available in your PHP installation, it requires extensions PECL intl >= 1.0.2 and PECL idn >= 0.1.

Also keep in mind that IPv4 or IPv6 as domain part in email (for example user@[IPv6:2001:db8::1]) cannot be validated, only named hosts can.

See more here.

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After reading the answers here, this is what I ended up with:

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;
}

참고URL : https://stackoverflow.com/questions/12026842/how-to-validate-an-email-address-in-php