Get domain name (not subdomain) in php
Well you can use parse_url to get the host:
$info = parse_url($url);
$host = $info['host'];
Then, you can do some fancy stuff to get only the TLD and the Host
$host_names = explode(".", $host);
$bottom_host_name = $host_names[count($host_names)-2] . "." . $host_names[count($host_names)-1];
Not very elegant, but should work.
If you want an explanation, here it goes:
First we grab everything between the scheme (http://, etc), by using parse_url's capabilities to... well.... parse URL's. :)
Then we take the host name, and separate it into an array based on where the periods fall, so test.world.hello.myname would become:
array("test", "world", "hello", "myname");
After that, we take the number of elements in the array (4).
Then, we subtract 2 from it to get the second to last string (the hostname, or example, in your example)
Then, we subtract 1 from it to get the last string (because array keys start at 0), also known as the TLD
Then we combine those two parts with a period, and you have your base host name.
It is not possible to get the domain name without using a TLD list to compare with as their exist many cases with completely the same structure and length:
nas.db.de (Subdomain)
bbc.co.uk (Top-Level-Domain)
www.uk.com (Subdomain)
big.uk.com (Second-Level-Domain)
Mozilla's public suffix list should be the best option as it is used by all major browsers:
https://publicsuffix.org/list/public_suffix_list.dat
Feel free to use my function:
function tld_list($cache_dir=null) {
// we use "/tmp" if $cache_dir is not set
$cache_dir = isset($cache_dir) ? $cache_dir : sys_get_temp_dir();
$lock_dir = $cache_dir . '/public_suffix_list_lock/';
$list_dir = $cache_dir . '/public_suffix_list/';
// refresh list all 30 days
if (file_exists($list_dir) && @filemtime($list_dir) + 2592000 > time()) {
return $list_dir;
}
// use exclusive lock to avoid race conditions
if (!file_exists($lock_dir) && @mkdir($lock_dir)) {
// read from source
$list = @fopen('https://publicsuffix.org/list/public_suffix_list.dat', 'r');
if ($list) {
// the list is older than 30 days so delete everything first
if (file_exists($list_dir)) {
foreach (glob($list_dir . '*') as $filename) {
unlink($filename);
}
rmdir($list_dir);
}
// now set list directory with new timestamp
mkdir($list_dir);
// read line-by-line to avoid high memory usage
while ($line = fgets($list)) {
// skip comments and empty lines
if ($line[0] == '/' || !$line) {
continue;
}
// remove wildcard
if ($line[0] . $line[1] == '*.') {
$line = substr($line, 2);
}
// remove exclamation mark
if ($line[0] == '!') {
$line = substr($line, 1);
}
// reverse TLD and remove linebreak
$line = implode('.', array_reverse(explode('.', (trim($line)))));
// we split the TLD list to reduce memory usage
touch($list_dir . $line);
}
fclose($list);
}
@rmdir($lock_dir);
}
// repair locks (should never happen)
if (file_exists($lock_dir) && mt_rand(0, 100) == 0 && @filemtime($lock_dir) + 86400 < time()) {
@rmdir($lock_dir);
}
return $list_dir;
}
function get_domain($url=null) {
// obtain location of public suffix list
$tld_dir = tld_list();
// no url = our own host
$url = isset($url) ? $url : $_SERVER['SERVER_NAME'];
// add missing scheme ftp:// http:// ftps:// https://
$url = !isset($url[5]) || ($url[3] != ':' && $url[4] != ':' && $url[5] != ':') ? 'http://' . $url : $url;
// remove "/path/file.html", "/:80", etc.
$url = parse_url($url, PHP_URL_HOST);
// replace absolute domain name by relative (http://www.dns-sd.org/TrailingDotsInDomainNames.html)
$url = trim($url, '.');
// check if TLD exists
$url = explode('.', $url);
$parts = array_reverse($url);
foreach ($parts as $key => $part) {
$tld = implode('.', $parts);
if (file_exists($tld_dir . $tld)) {
return !$key ? '' : implode('.', array_slice($url, $key - 1));
}
// remove last part
array_pop($parts);
}
return '';
}
What it makes special:
- it accepts every input like URLs, hostnames or domains with- or without scheme
- the list is downloaded row-by-row to avoid high memory usage
- it creates a new file per TLD in a cache folder so
get_domain()only needs to check throughfile_exists()if it exists so it does not need to include a huge database on every request like TLDExtract does it. - the list will be automatically updated every 30 days
Test:
$urls = array(
'http://www.example.com',// example.com
'http://subdomain.example.com',// example.com
'http://www.example.uk.com',// example.uk.com
'http://www.example.co.uk',// example.co.uk
'http://www.example.com.ac',// example.com.ac
'http://example.com.ac',// example.com.ac
'http://www.example.accident-prevention.aero',// example.accident-prevention.aero
'http://www.example.sub.ar',// sub.ar
'http://www.congresodelalengua3.ar',// congresodelalengua3.ar
'http://congresodelalengua3.ar',// congresodelalengua3.ar
'http://www.example.pvt.k12.ma.us',// example.pvt.k12.ma.us
'http://www.example.lib.wy.us',// example.lib.wy.us
'com',// empty
'.com',// empty
'http://big.uk.com',// big.uk.com
'uk.com',// empty
'www.uk.com',// www.uk.com
'.uk.com',// empty
'stackoverflow.com',// stackoverflow.com
'.foobarfoo',// empty
'',// empty
false,// empty
' ',// empty
1,// empty
'a',// empty
);
Recent version with explanations (German):
http://www.programmierer-forum.de/domainnamen-ermitteln-t244185.htm
My solution in https://gist.github.com/pocesar/5366899
and the tests are here http://codepad.viper-7.com/GAh1tP
It works with any TLD, and hideous subdomain patterns (up to 3 subdomains).
There's a test included with many domain names.
Won't paste the function here because of the weird indentation for code in StackOverflow (could have fenced code blocks like github)