idn_to_ascii

(PHP 5 >= 5.3.0, PHP 7, PHP 8, PECL intl >= 1.0.2, PECL idn >= 0.1)

idn_to_ascii — ドメイン名をIDNAのASCII形式に変換する

説明

手続き型

idn_to_ascii(
    string $domain,
    int $flags = IDNA_DEFAULT,
    int $variant = INTL_IDNA_VARIANT_UTS46,
    array &$idna_info = null
): string|false

Unicode のドメイン名を、IDNAが定めたASCII形式に変換します。

パラメータ

domain: 変換するドメイン名。UTF-8 にエンコードされている必要があります。
flags: 変換オプション - IDNA_ ではじまる定数 (IDNA_ERROR_* 定数を除く) の組み合わせです。
variant: IDNA 2003 の場合は INTL_IDNA_VARIANT_2003 (PHP 7.2.0 以降は非推奨)、あるいは UTS #46 の場合は INTL_IDNA_VARIANT_UTS46 (ICU 4.6 以降のみ利用可能)。
idna_info: このパラメータを使うのは、variant が INTL_IDNA_VARIANT_UTS46 の場合だけです。このとき、このパラメータには 'result'、 'isTransitionalDifferent'、そして 'errors' の三つのキーを含む配列が入ります。 'result' にはおそらく不正だと考えられる変換結果、 'isTransitionalDifferent' には UTS #46 の非移行的な機能を使って結果を変更したかどうかをあらわす boolean 値、そして 'errors' はエラー定数 IDNA_ERROR_* のビットセットを表します。

戻り値

IDNA のASCII形式でエンコードされたドメイン名。失敗した場合に false を返します

変更履歴

バージョン	説明
7.4.0	`variant` のデフォルト値が `INTL_IDNA_VARIANT_UTS46` となり、その代わりに `INTL_IDNA_VARIANT_2003` は非推奨となりました。
7.2.0	`INTL_IDNA_VARIANT_2003` は非推奨です。代わりに `INTL_IDNA_VARIANT_UTS46` を使用してください。

例

例1 idn_to_ascii() の例

<?php

echo idn_to_ascii('tast.de'); 

?>

上の例の出力は以下となります。

xn--tst-qla.de

参考

idn_to_utf8() - IDNAのASCII方式でエンコードされたドメイン名をUnicodeに変換する

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User Contributed Notes 4 notes

down

mschrieck at gmail dot com ¶

7 years ago

To convert IDN Domains with the IDNA2008 definition use following command.

idn_to_ascii('teßt.com',IDNA_NONTRANSITIONAL_TO_ASCII,INTL_IDNA_VARIANT_UTS46)

The result is then as expected

xn--tet-6ka.com

down

edible dot email at gmail dot com ¶

12 years ago

The notes on this function are not very clear and a little misleading.



Firstly, <=5.3, you will need to make use of one of several scripts or classes available on the internet which might, or might not, require the installation of of the intl and idn PECL extensions ...and you will need to have !<4.0 in order to be able to install both.



Secondly, if you have >=5.4 you will not require the PECL extensions.



Third, use of utf8_encode() is not necessary.  In fact, it will potentially prevent idn_to_ascii() from working at all.



On my setup it was necessary to change the charset in the script meta tags to UTF-8:



<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />



...and to change charset_default in the php.ini file (/usr/local/lib/php.ini, whereis php.ini, find / -name php.ini):



default_charset = "UTF-8"



The above changes mean that idn_to_ascii() can now be used with that syntax (no need for utf8_encode()).  Previously, the function worked to convert some IDNs, but failed to convert Japanese and Cyrillic IDNs.  Further, no additional locales were enabled or added, and Apache's charset file was left unmodified.



It is also important to remember only to apply the function where required, eg:



idn_to_ascii(cåsino.com) // is wrong



...whereas...



iden_to_ascii(cåsino) // is right



...and also be aware of text editors that don't support UTF-8 encoding, or the $domain = 'cåsino' value will end up as $domain = '??????' ...and the function will fail.



I have found that Notepad++ easily and reliably handles UTF-8 encoding that works for this function using UTF-8 as the encoding option, not UTF-8 without BOM.

down

alexchexes at gmail dot com ¶

1 year ago

idn_to_ascii and idn_to_utf8 functions don't properly handle full URLs (i.e. with schema and paths), so here's the helper functions which handles all URLs, including ones with path but without a scheme

<?php
/**
 * Converts URLS to punycode  
 * It doesn't url-encodes other parts
 * The initial code from snipp dor ru website, here is modified version that handles urls without scheme
 */
function punycode_encode($url)
{
    $no_scheme = false;
    if (!preg_match('/^.+?:\/\//', $url) && substr($url, 0, 2) !== '//') {
        $url = '//' . $url;
        $no_scheme = true;
    }

    $parts = parse_url($url);
 
    $out = '';
    if (!empty($parts['scheme']))   $out .= $parts['scheme'] . ':';
    if (!empty($parts['host']))     $out .= '//';
    if (!empty($parts['user']))     $out .= $parts['user'];
    if (!empty($parts['pass']))     $out .= ':' . $parts['pass'];
    if (!empty($parts['user']))     $out .= '@';
    if (!empty($parts['host']))     $out .= idn_to_ascii($parts['host']);
    if (!empty($parts['port']))     $out .= ':' . $parts['port'];
    if (!empty($parts['path']))     $out .= $parts['path'];
    if (!empty($parts['query']))    $out .= '?' . $parts['query'];
    if (!empty($parts['fragment'])) $out .= '#' . $parts['fragment'];

    if ($no_scheme) {
        $out = substr($out, 2);
    }
 
    return $out;
}

function punycode_decode($url)
{
    $no_scheme = false;
    if (!preg_match('/^.+?:\/\//', $url) && substr($url, 0, 2) !== '//') {
        $url = '//' . $url;
        $no_scheme = true;
    }

    $parts = parse_url($url);
    $out = '';
    if (!empty($parts['scheme']))   $out .= $parts['scheme'] . ':';
    if (!empty($parts['host']))     $out .= '//';
    if (!empty($parts['user']))     $out .= $parts['user'];
    if (!empty($parts['pass']))     $out .= ':' . $parts['pass'];
    if (!empty($parts['user']))     $out .= '@';
    if (!empty($parts['host']))     $out .= idn_to_utf8($parts['host']);
    if (!empty($parts['port']))     $out .= ':' . $parts['port'];
    if (!empty($parts['path']))     $out .= $parts['path'];
    if (!empty($parts['query']))    $out .= '?' . $parts['query'];
    if (!empty($parts['fragment'])) $out .= '#' . $parts['fragment'];
 
    if ($no_scheme) {
        $out = substr($out, 2);
    }
    
    return $out;
}

down

mpf at mk dot de ¶

11 months ago

The documentation ist not clear what failure in the return section means. This should be substituted to something like this:

"Returns failure if the given string could not be converted".

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