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```{index} single: IO::Socket::SSL::PublicSuffix
```

# IO::Socket::SSL::PublicSuffix

provide access to Mozilla's list of effective TLD names

## SYNOPSIS

```perl
   # use builtin default
   use IO::Socket::SSL::PublicSuffix;
   $ps = IO::Socket::SSL::PublicSuffix->default;

   # load from string
   $ps = IO::Socket::SSL::PublicSuffix->from_string("*.uk\n*");

   # load from file or file handle
   $ps = IO::Socket::SSL::PublicSuffix->from_file($filename);
   $ps = IO::Socket::SSL::PublicSuffix->from_file(\*STDIN);


   # --- string in -> string out
   # $rest -> whatever.host
   # $tld  -> co.uk
   my ($rest,$tld) = $ps->public_suffix('whatever.host.co.uk');
   my $tld = $ps->public_suffix('whatever.host.co.uk');

   # $root_domain -> host.co.uk
   my $root_domain = $ps->public_suffix('whatever.host.co.uk', 1);

   # --- array in -> array out
   # $rest -> [qw(whatever host)]
   # $tld  -> [qw(co uk)]
   my ($rest,$tld) = $ps->public_suffix([qw(whatever host co uk)]);

----

   # To update this file with the current list:
   perl -MIO::Socket::SSL::PublicSuffix -e 'IO::Socket::SSL::PublicSuffix::update_self_from_url()'
```

## DESCRIPTION

This module uses the list of effective top level domain names from the mozilla
project to determine the public top level domain for a given hostname.

### Method

- class->default(%args)

    Returns object with builtin default.
    `min_suffix` can be given in `%args` to specify the minimal suffix, default
    is 1.

- class->from\_string(string,%args)

    Returns object with configuration from string.
    See method `default` for `%args`.

- class->from\_file( file name| file handle, %args )

    Returns object with configuration from file or file handle.
    See method `default` for `%args`.

- $self->public\_suffix( $host|\\@host, \[ $add \] )

    In array context the function returns the non-tld part and the tld part of the
    given hostname, in scalar context only the tld part.
    It adds `$add` parts of the non-tld part to the tld, e.g. with `$add=1` it
    will return the root domain.

    If there were no explicit matches against the public suffix configuration it
    will fall back to a suffix of length 1.

    The function accepts a string or an array-ref (e.g. host split by `.`). In the
    first case it will return string(s), in the latter case array-ref(s).

    International hostnames or labels can be in ASCII (IDNA form starting with
    `xn--`) or unicode. In the latter case an IDNA handling library needs to be
    available.  [URI](https://metacpan.org/pod/URI) is preferred, but [Net::IDN:::Encode](https://metacpan.org/pod/Net::IDN:::Encode), [Net::LibIDN](https://metacpan.org/pod/Net::LibIDN) are
    still supported.

- ($self|class)->can\_idn

    Returns true if IDN support is available.

## FILES

http://publicsuffix.org/list/effective\_tld\_names.dat

## SEE ALSO

Domain::PublicSuffix, Mozilla::PublicSuffix

## BUGS

```text
Q: Why yet another module, we already have L<Domain::PublicSuffix> and
   L<Mozilla::PublicSuffix>.
A: Because the public suffix data change more often than these modules do,
   IO::Socket::SSL needs this list and it is more easy this way to keep it
   up-to-date.
```

## AUTHOR

Steffen Ullrich