goranseric
4/11/2013 - 8:27 PM

PHP code to get the domain name without subdomains (includes the tld, and the special types from IANA). Don't have support for unicode domai

PHP code to get the domain name without subdomains (includes the tld, and the special types from IANA). Don't have support for unicode domain names.

<?php
/**
 * @param string $domain Pass $_SERVER['SERVER_NAME'] here
 * @param bool $debug
 *
 * @debug bool $debug
 * @return string
 */
function get_domain($domain, $debug = false)
{
	$original = $domain = strtolower($domain);

	if (filter_var($domain, FILTER_VALIDATE_IP)) { return $domain; }

	$debug ? print('<strong style="color:green">&raquo;</strong> Parsing: '.$original) : false;

	$arr = array_slice(array_filter(explode('.', $domain, 4), function($value){
		return $value !== 'www';
	}), 0); //rebuild array indexes

	if (count($arr) > 2)
	{
		$count = count($arr);
		$_sub = explode('.', $count === 4 ? $arr[3] : $arr[2]);

		$debug ? print(" (parts count: {$count})") : false;

		if (count($_sub) === 2) // two level TLD
		{
			$removed = array_shift($arr);
			if ($count === 4) // got a subdomain acting as a domain
			{
				$removed = array_shift($arr);
			}
			$debug ? print("<br>\n" . '[*] Two level TLD: <strong>' . join('.', $_sub) . '</strong> ') : false;
		}
		elseif (count($_sub) === 1) // one level TLD
		{
			$removed = array_shift($arr); //remove the subdomain

			if (strlen($_sub[0]) === 2 && $count === 3) // TLD domain must be 2 letters
			{
				array_unshift($arr, $removed);
			}
			else
			{
				// non country TLD according to IANA
				$tlds = array(
					'aero',
					'arpa',
					'asia',
					'biz',
					'cat',
					'com',
					'coop',
					'edu',
					'gov',
					'info',
					'jobs',
					'mil',
					'mobi',
					'museum',
					'name',
					'net',
					'org',
					'post',
					'pro',
					'tel',
					'travel',
					'xxx',
				);

				if (count($arr) > 2 && in_array($_sub[0], $tlds) !== false) //special TLD don't have a country
				{
					array_shift($arr);
				}
			}
			$debug ? print("<br>\n" .'[*] One level TLD: <strong>'.join('.', $_sub).'</strong> ') : false;
		}
		else // more than 3 levels, something is wrong
		{
			for ($i = count($_sub); $i > 1; $i--)
			{
				$removed = array_shift($arr);
			}
			$debug ? print("<br>\n" . '[*] Three level TLD: <strong>' . join('.', $_sub) . '</strong> ') : false;
		}
	}
	elseif (count($arr) === 2)
	{
		$arr0 = array_shift($arr);

		if (strpos(join('.', $arr), '.') === false
			&& in_array($arr[0], array('localhost','test','invalid')) === false) // not a reserved domain
		{
			$debug ? print("<br>\n" .'Seems invalid domain: <strong>'.join('.', $arr).'</strong> re-adding: <strong>'.$arr0.'</strong> ') : false;
			// seems invalid domain, restore it
			array_unshift($arr, $arr0);
		}
	}

	$debug ? print("<br>\n".'<strong style="color:gray">&laquo;</strong> Done parsing: <span style="color:red">' . $original . '</span> as <span style="color:blue">'. join('.', $arr) ."</span><br>\n") : false;

	return join('.', $arr);
}

$urls = array(
	'www.example.com' => 'example.com',
	'example.com' => 'example.com',
	'example.com.br' => 'example.com.br',
	'www.example.com.br' => 'example.com.br',
	'www.example.gov.br' => 'example.gov.br',
	'localhost' => 'localhost',
	'www.localhost' => 'localhost',
	'subdomain.localhost' => 'localhost',
	'www.subdomain.example.com' => 'example.com',
	'subdomain.example.com' => 'example.com',
	'subdomain.example.com.br' => 'example.com.br',
	'www.subdomain.example.com.br' => 'example.com.br',
	'www.subdomain.example.biz.br' => 'example.biz.br',
	'subdomain.example.biz.br' => 'example.biz.br',
	'subdomain.example.net' => 'example.net',
	'www.subdomain.example.net' => 'example.net',
	'www.subdomain.example.co.kr' => 'example.co.kr',
	'subdomain.example.co.kr' => 'example.co.kr',
	'example.co.kr' => 'example.co.kr',
	'example.jobs' => 'example.jobs',
	'www.example.jobs' => 'example.jobs',
	'subdomain.example.jobs' => 'example.jobs',
	'insane.subdomain.example.jobs' => 'example.jobs',
	'insane.subdomain.example.com.br' => 'example.com.br',
	'www.doubleinsane.subdomain.example.com.br' => 'example.com.br',
	'www.subdomain.example.jobs' => 'example.jobs',
	'test' => 'test',
	'www.test' => 'test',
	'subdomain.test' => 'test',
	'www.detran.sp.gov.br' => 'sp.gov.br',
	'www.mp.sp.gov.br' => 'sp.gov.br',
	'ny.library.museum' => 'library.museum',
	'www.ny.library.museum' => 'library.museum',
	'ny.ny.library.museum' => 'library.museum',
	'www.library.museum' => 'library.museum',
	'info.abril.com.br' => 'abril.com.br',
	'127.0.0.1' => '127.0.0.1',
	'::1' => '::1',
);

$failed = 0;
$total = count($urls);

foreach ($urls as $from => $expected)
{
	$from = get_domain($from, true);
	if ($from !== $expected)
	{
		$failed++;
		print("<div style='color:fuchsia;'>expected {$from} to be {$expected}</div>");
	}
}

if ($failed)
{
	print("{$failed} tests failed out of {$total}");
}
else
{
	print("Success");
}