RegDom - Registered Domain Check in PHP

Object oriented PHP library for querying Mozilla's Public Suffix List to determine the registrable domain portion of URLs and validate cookie domains per RFC 6265. Adapted from Florian Sager's regdom library.

For more information on public suffixes, see publicsuffix.org.

Requirements

• PHP 7.4 or later
• ext-intl recommended (for internationalized domain name support)

Installation

composer require xoops/regdom

Usage

Extracting the Registered Domain

use Xoops\RegDom\RegisteredDomain;

$regdom = new RegisteredDomain();

echo $regdom->getRegisteredDomain('https://www.google.com/');
// Output: google.com

echo $regdom->getRegisteredDomain('theregister.co.uk');
// Output: theregister.co.uk

var_dump($regdom->getRegisteredDomain('co.uk'));
// Output: NULL (co.uk is a public suffix, not a registrable domain)

// IDN support (requires ext-intl)
echo $regdom->getRegisteredDomain('www.münchen.de');
// Output: münchen.de

Cookie Domain Validation (RFC 6265)

use Xoops\RegDom\RegisteredDomain;

// Validates if a cookie domain is appropriate for a given host
RegisteredDomain::domainMatches('www.example.com', 'example.com');  // true
RegisteredDomain::domainMatches('example.com', 'com');              // false (public suffix)
RegisteredDomain::domainMatches('google.com', 'facebook.com');      // false (cross-domain)
RegisteredDomain::domainMatches('192.168.1.1', '192.168.1.1');      // false (IP addresses)

Querying the Public Suffix List

use Xoops\RegDom\PublicSuffixList;

$psl = new PublicSuffixList();

$psl->isPublicSuffix('com');        // true
$psl->isPublicSuffix('co.uk');      // true
$psl->isPublicSuffix('example.com'); // false

$psl->getPublicSuffix('www.example.co.uk'); // 'co.uk'

$psl->isException('www.ck'); // true (PSL exception rule)

Checking PSL Cache Status

$metadata = $psl->getMetadata();
// Returns: active_cache, last_updated, days_old, rule_counts, needs_update

Updating the Public Suffix List

composer run update-psl

Set the XOOPS_SKIP_PSL_UPDATE environment variable to skip automatic PSL updates during composer install/update (useful in CI or restricted networks).

Configuration

XOOPS_COOKIE_DOMAIN_USE_PSL

When defined and set to false, disables PSL-based validation in RegisteredDomain::domainMatches(). Defaults to true when undefined.

XOOPS_SKIP_PSL_UPDATE

Environment variable. When set (to any value), prevents automatic PSL download during Composer post-install/update hooks.

Development

composer install          # Install dependencies
composer ci               # Run all checks: lint + analyse + test
composer test             # Run PHPUnit tests
composer lint             # Check code style (PSR-12)
composer analyse          # Run PHPStan (level max)
composer fix              # Auto-fix code style issues

Credits

Reg-dom was written by Florian Sager, 2009-02-05, sager@agitos.de

Marcus Bointon's adapted code: https://github.com/Synchro/regdom-php

License

The PHP library code in this repository is licensed under the Apache License 2.0. See LICENSE.txt for the full Apache 2.0 license text.

The bundled Public Suffix List data/cache is derived from Mozilla's Public Suffix List and is available under the Mozilla Public License 2.0 (MPL-2.0). For details, see https://www.mozilla.org/en-US/MPL/2.0/ and https://publicsuffix.org/.