(PECL idn >= 0.1)
idn_to_ascii — Convert UTF-8 encoded domain name to ASCII
This function converts a UTF-8 encoded domain name to ASCII according to the IDNA toUnicode() specification. If the input has non-ASCII characters, the output will be in the "xn--" ACE notation.
The UTF-8 encoded domain name.
If e.g. an ISO-8859-1 (aka Western Europe latin1) encoded string is passed it will be converted into an ACE encoded "xn--" string. It will not be the one you expected though!
Will be set to the IDNA error code.
The ACE encoded version of the domain name or FALSE in case of an error.
If an error occurs FALSE is returned and the optional errorcode is set. In addition a E_WARNING message is printed.
Example #1 idn_to_ascii() example
First a simple example and then one explaining how to catch errors.
<?php
// ISO-8859-1 encoded string
echo idn_to_ascii(utf8_encode('t?st.de')));
// Cannot convert a domain name to ASCII that contains non-ASCII chars but already starts with "xn--"
$ascii = idn_to_ascii("xn--".chr(0xC3).chr(0xA4), $errorcode);
if ($ascii === false) {
printf("Detected error %d: %s\n", $errorcode, idn_strerror($errorcode));
}
?>
上例的输出类似于：
xn--tst-qla.de Detected error 8: Input already contain ACE prefix (`xn--')