PHP Getting Domain Name From Subdomain

Stackoverflow Question Archive:

• How to get domain name from url?
• Check if domain equals value?
• How do I get the base url?

print get_domain("http://somedomain.co.uk"); // outputs 'somedomain.co.uk'function get_domain($url){  $pieces = parse_url($url);  $domain = isset($pieces['host']) ? $pieces['host'] : '';  if (preg_match('/(?P<domain>[a-z0-9][a-z0-9\-]{1,63}\.[a-z\.]{2,6})$/i', $domain, $regs)) {    return $regs['domain'];  }  return false;}

If you want a fast simple solution, without external calls and checking against predefined arrays. Works for new domains like "www.domain.gallery" also, unlike the most popular answer.

function get_domain($host){  $myhost = strtolower(trim($host));  $count = substr_count($myhost, '.');  if($count === 2){    if(strlen(explode('.', $myhost)[1]) > 3) $myhost = explode('.', $myhost, 2)[1];  } else if($count > 2){    $myhost = get_domain(explode('.', $myhost, 2)[1]);  }  return $myhost;}

• domain.com -> domain.com
• sub.domain.com -> domain.com
• www.domain.com -> domain.com
• www.sub.sub.domain.com -> domain.com
• domain.co.uk -> domain.co.uk
• sub.domain.co.uk -> domain.co.uk
• www.domain.co.uk -> domain.co.uk
• www.sub.sub.domain.co.uk -> domain.co.uk
• domain.photography -> domain.photography
• www.domain.photography -> domain.photography
• www.sub.domain.photography -> domain.photography

I would do something like the following:

// hierarchical array of top level domains$tlds = array(    'com' => true,    'uk' => array(        'co' => true,        // …    ),    // …);$domain = 'here.example.co.uk';// split domain$parts = explode('.', $domain);$tmp = $tlds;// travers the tree in reverse order, from right to leftforeach (array_reverse($parts) as $key => $part) {    if (isset($tmp[$part])) {        $tmp = $tmp[$part];    } else {        break;    }}// build the resultvar_dump(implode('.', array_slice($parts, - $key - 1)));