问题
I have a URL which can be any of the following formats:
http://example.com
https://example.com
http://example.com/foo
http://example.com/foo/bar
www.example.com
example.com
foo.example.com
www.foo.example.com
foo.bar.example.com
http://foo.bar.example.com/foo/bar
example.net/foo/bar
Essentially, I need to be able to match any normal URL. How can I extract example.com (or .net, whatever the tld happens to be. I need this to work with any TLD.) from all of these via a single regex?
回答1:
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.
回答2:
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)
回答3:
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:
- www.db.de (Subdomain) versus bbc.co.uk (Domain)
- big.uk.com (SLD) versus www.uk.com (TLD)
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
回答4:
$onlyHostName = implode('.', array_slice(explode('.', parse_url($link, PHP_URL_HOST)), -2));
回答5:
I think the best way to handle this problem is:
$second_level_domains_regex = '/\.asn\.au$|\.com\.au$|\.net\.au$|\.id\.au$|\.org\.au$|\.edu\.au$|\.gov\.au$|\.csiro\.au$|\.act\.au$|\.nsw\.au$|\.nt\.au$|\.qld\.au$|\.sa\.au$|\.tas\.au$|\.vic\.au$|\.wa\.au$|\.co\.at$|\.or\.at$|\.priv\.at$|\.ac\.at$|\.avocat\.fr$|\.aeroport\.fr$|\.veterinaire\.fr$|\.co\.hu$|\.film\.hu$|\.lakas\.hu$|\.ingatlan\.hu$|\.sport\.hu$|\.hotel\.hu$|\.ac\.nz$|\.co\.nz$|\.geek\.nz$|\.gen\.nz$|\.kiwi\.nz$|\.maori\.nz$|\.net\.nz$|\.org\.nz$|\.school\.nz$|\.cri\.nz$|\.govt\.nz$|\.health\.nz$|\.iwi\.nz$|\.mil\.nz$|\.parliament\.nz$|\.ac\.za$|\.gov\.za$|\.law\.za$|\.mil\.za$|\.nom\.za$|\.school\.za$|\.net\.za$|\.co\.uk$|\.org\.uk$|\.me\.uk$|\.ltd\.uk$|\.plc\.uk$|\.net\.uk$|\.sch\.uk$|\.ac\.uk$|\.gov\.uk$|\.mod\.uk$|\.mil\.uk$|\.nhs\.uk$|\.police\.uk$/';
$domain = $_SERVER['HTTP_HOST'];
$domain = explode('.', $domain);
$domain = array_reverse($domain);
if (preg_match($second_level_domains_regex, $_SERVER['HTTP_HOST']) {
$domain = "$domain[2].$domain[1].$domain[0]";
} else {
$domain = "$domain[1].$domain[0]";
}
回答6:
I recommend using TLDExtract library for all operations with domain name.
回答7:
There are two ways to extract subdomain from a host:
The first method that is more accurate is to use a database of tlds (like public_suffix_list.dat) and match domain with it. This is a little heavy in some cases. There are some PHP classes for using it like php-domain-parser and TLDExtract.
The second way is not as accurate as the first one, but is very fast and it can give the correct answer in many case, I wrote this function for it:
function get_domaininfo($url) { // regex can be replaced with parse_url preg_match("/^(https|http|ftp):\/\/(.*?)\//", "$url/" , $matches); $parts = explode(".", $matches[2]); $tld = array_pop($parts); $host = array_pop($parts); if ( strlen($tld) == 2 && strlen($host) <= 3 ) { $tld = "$host.$tld"; $host = array_pop($parts); } return array( 'protocol' => $matches[1], 'subdomain' => implode(".", $parts), 'domain' => "$host.$tld", 'host'=>$host,'tld'=>$tld ); }Example:
print_r(get_domaininfo('http://mysubdomain.domain.co.uk/index.php'));Returns:
Array ( [protocol] => https [subdomain] => mysubdomain [domain] => domain.co.uk [host] => domain [tld] => co.uk )
回答8:
Here's a function I wrote to grab the domain without subdomain(s), regardless of whether the domain is using a ccTLD or a new style long TLD, etc... There is no lookup or huge array of known TLDs, and there's no regex. It can be a lot shorter using the ternary operator and nesting, but I expanded it for readability.
// Per Wikipedia: "All ASCII ccTLD identifiers are two letters long,
// and all two-letter top-level domains are ccTLDs."
function topDomainFromURL($url) {
$url_parts = parse_url($url);
$domain_parts = explode('.', $url_parts['host']);
if (strlen(end($domain_parts)) == 2 ) {
// ccTLD here, get last three parts
$top_domain_parts = array_slice($domain_parts, -3);
} else {
$top_domain_parts = array_slice($domain_parts, -2);
}
$top_domain = implode('.', $top_domain_parts);
return $top_domain;
}
回答9:
echo getDomainOnly("http://example.com/foo/bar");
function getDomainOnly($host){
$host = strtolower(trim($host));
$host = ltrim(str_replace("http://","",str_replace("https://","",$host)),"www.");
$count = substr_count($host, '.');
if($count === 2){
if(strlen(explode('.', $host)[1]) > 3) $host = explode('.', $host, 2)[1];
} else if($count > 2){
$host = getDomainOnly(explode('.', $host, 2)[1]);
}
$host = explode('/',$host);
return $host[0];
}
回答10:
I had problems with the solution provided by pocesar. When I would use for instance subdomain.domain.nl it would not return domain.nl. Instead it would return subdomain.domain.nl Another problem was that domain.com.br would return com.br
I am not sure but i fixed these issues with the following code (i hope it will help someone, if so I am a happy man):
function get_domain($domain, $debug = false){
$original = $domain = strtolower($domain);
if (filter_var($domain, FILTER_VALIDATE_IP)) {
return $domain;
}
$debug ? print('<strong style="color:green">»</strong> Parsing: '.$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($arr[0]) === 2 && $count === 3){ // TLD domain must be 2 letters
array_unshift($arr, $removed);
}elseif(strlen($arr[0]) === 3 && $count === 3){
array_unshift($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">«</strong> Done parsing: <span style="color:red">' . $original . '</span> as <span style="color:blue">'. join('.', $arr) ."</span><br>\n") : false;
return join('.', $arr);
}
回答11:
Here's one that works for all domains, including those with second level domains like "co.uk"
function strip_subdomains($url){
# credits to gavingmiller for maintaining this list
$second_level_domains = file_get_contents("https://raw.githubusercontent.com/gavingmiller/second-level-domains/master/SLDs.csv");
# presume sld first ...
$possible_sld = implode('.', array_slice(explode('.', $url), -2));
# and then verify it
if (strpos($second_level_domains, $possible_sld)){
return implode('.', array_slice(explode('.', $url), -3));
} else {
return implode('.', array_slice(explode('.', $url), -2));
}
}
Looks like there's a duplicate question here: delete-subdomain-from-url-string-if-subdomain-is-found
回答12:
Simply try this:
preg_match('/(www.)?([^.]+\.[^.]+)$/', $yourHost, $matches);
echo "domain name is: {$matches[0]}\n";
this working for majority of domains.
回答13:
Simply try this:
<?php
$host = $_SERVER['HTTP_HOST'];
preg_match("/[^\.\/]+\.[^\.\/]+$/", $host, $matches);
echo "domain name is: {$matches[0]}\n";
?>
来源：https://stackoverflow.com/questions/2679618/get-domain-name-not-subdomain-in-php