PHP Manual: idn_to

Description

Procedural style

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

This function converts a Unicode domain name to an IDNA ASCII-compatible format in lowercase.

Parameters

domain: The domain to convert, which must be UTF-8 encoded.
flags: Conversion options - combination of IDNA_* constants (except IDNA_ERROR_* constants).
variant: Either INTL_IDNA_VARIANT_2003 (deprecated as of PHP 7.2.0) for IDNA 2003 or INTL_IDNA_VARIANT_UTS46 (only available as of ICU 4.6) for UTS #46.
idna_info: This parameter can be used only if INTL_IDNA_VARIANT_UTS46 was used for variant. In that case, it will be filled with an array with the keys 'result', the possibly illegal result of the transformation, 'isTransitionalDifferent', a boolean indicating whether the usage of the transitional mechanisms of UTS #46 either has or would have changed the result and 'errors', which is an int representing a bitset of the error constants IDNA_ERROR_*.

Return Values

The domain name encoded in ASCII-compatible form, or false on failure

Changelog

Version	Description
8.4.0	Now throws a ValueError if the `domain` parameter is empty.
8.4.0	Now throws a ValueError if the `variant` parameter is not `INTL_IDNA_VARIANT_UTS46`.
7.4.0	The default value of `variant` is now `INTL_IDNA_VARIANT_UTS46` instead of the deprecated `INTL_IDNA_VARIANT_2003`.
7.2.0	`INTL_IDNA_VARIANT_2003` has been deprecated; use `INTL_IDNA_VARIANT_UTS46` instead.

Examples

Example #1 idn_to_ascii() example

<?php

echo idn_to_ascii('täst.de'); 

?>

The above example will output:

xn--tst-qla.de

Example #2 All-ASCII domain names are just converted to lowercase

<?php

var_dump(idn_to_ascii('Example.com'));

?>