PHP 7.0.6 Released

    idn_to_utf8

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

    idn_to_utf8 — Convert domain name from IDNA ASCII to Unicode.

    Description

    Procedural style

    string idn_to_utf8 ( string $domain [, int $options = 0 [, int $variant = INTL_IDNA_VARIANT_2003 [, array &$idna_info ]]] )

    This function converts Unicode domain name from IDNA ASCII-compatible format to plain Unicode, encoded in UTF-8.

    Parameters

    domain

    Domain to convert in IDNA ASCII-compatible format.

    options

    Conversion options - combination of IDNA_* constants (except IDNA_ERROR_* constants).

    variant

    Either INTL_IDNA_VARIANT_2003 for IDNA 2003 or INTL_IDNA_VARIANT_UTS46 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

    Domain name in Unicode, encoded in UTF-8. or FALSE on failure

    Changelog

    Version Description
    5.4.0/PECL 2.0.0b1 Added the parameters variant and idna_info; UTS #46 support.

    Examples

    Example #1 idn_to_utf8() example

    <?php

    echo idn_to_utf8('xn--tst-qla.de'); 

    ?>

    The above example will output:

    täst.de

    See Also

    • idn_to_unicode()

    User Contributed Notes

    kushik.com
    2 years ago
    <?php
    // for those who has PHP older than version 5.3
    class IDN {
            // adapt bias for punycode algorithm
            private static function punyAdapt(
                $delta,
                $numpoints,
                $firsttime
            ) {
                $delta = $firsttime ? $delta / 700 : $delta / 2;
                $delta += $delta / $numpoints;
            for (    $k = 0; $delta > 455; $k += 36)
                    $delta = intval($delta / 35);
            return     $k + (36 * $delta) / ($delta + 38);
        }

            // translate character to punycode number
            private static function decodeDigit($cp) {
                $cp = strtolower($cp);
            if (    $cp >= 'a' && $cp <= 'z')
                return     ord($cp) - ord('a');
            elseif (    $cp >= '0' && $cp <= '9')
                return     ord($cp) - ord('0')+26;
        }

            // make utf8 string from unicode codepoint number
            private static function utf8($cp) {
            if (    $cp < 128) return chr($cp);
            if (    $cp < 2048)
                return     chr(192+($cp >> 6)).chr(128+($cp & 63));
            if (    $cp < 65536) return
                    chr(224+($cp >> 12)).
                    chr(128+(($cp >> 6) & 63)).
                    chr(128+($cp & 63));
            if (    $cp < 2097152) return
                    chr(240+($cp >> 18)).
                    chr(128+(($cp >> 12) & 63)).
                    chr(128+(($cp >> 6) & 63)).
                    chr(128+($cp & 63));
                // it should never get here
            }

            // main decoding function
            private static function decodePart($input) {
            if (    substr($input,0,4) != "xn--") // prefix check...
                    return $input;
                $input = substr($input,4); // discard prefix
                $a = explode("-",$input);
            if (    count($a) > 1) {
                    $input = str_split(array_pop($a));
                    $output = str_split(implode("-",$a));
            } else {
                    $output = array();
                    $input = str_split($input);
            }
                $n = 128; $i = 0; $bias = 72; // init punycode vars
                while (!empty($input)) {
                    $oldi = $i;
                    $w = 1;
                for (    $k = 36;;$k += 36) {
                        $digit = IDN::decodeDigit(array_shift($input));
                        $i += $digit * $w;
                    if (    $k <= $bias) $t = 1;
                    elseif (    $k >= $bias + 26) $t = 26;
                    else     $t = $k - $bias;
                    if (    $digit < $t) break;
                        $w *= intval(36 - $t);
                }
                    $bias = IDN::punyAdapt(
                        $i-$oldi,
                        count($output)+1,
                        $oldi == 0
                    );
                    $n += intval($i / (count($output) + 1));
                    $i %= count($output) + 1;
                    array_splice($output,$i,0,array(IDN::utf8($n)));
                    $i++;
            }
            return     implode("",$output);
        }

        public static function     decodeIDN($name) {
                // split it, parse it and put it back together
                return
                    implode(
                        ".",
                        array_map("IDN::decodePart",explode(".",$name))
                );
        }

    }
    echo     IDN::decodeIDN($_SERVER['HTTP_HOST']);
    ?>
    zedwood.com
    2 years ago
    @kushik.com:
    punyAdapt should be patched:
    <?php
            private static function punyAdapt($delta, $numpoints, $firsttime)
        {
                $delta = (int)($firsttime ? $delta / 700 : $delta / 2);
                $delta += (int)($delta / $numpoints);
            for(    $k = 0; $delta > 455; $k+=36)
                    $delta = (int)($delta / 35);
            }
            return     $k + (int)((36) * $delta / ($delta + 38));
        }
    ?>
    petrox81 at yahoo dot it
    2 years ago
    Why idn_to_utf8('xn--sorra-lqa.it') output xn--sorra-lqa.it?

    The correct output must be 'sßorra.it'
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