Parsing domain from a URL

Question

Check out parse_url():

$url = 'http://google.com/dhasjkdas/sadsdds/sdda/sdads.html';
$parse = parse_url($url);
echo $parse['host']; // prints 'google.com'

parse_url doesn't handle really badly mangled urls very well, but is fine if you generally expect decent urls.

$domain = str_ireplace('www.', '', parse_url($url, PHP_URL_HOST));

This would return the google.com for both http://google.com/... and http://www.google.com/...

From http://us3.php.net/manual/en/function.parse-url.php#93983

for some odd reason, parse_url returns the host (ex. example.com) as the path when no scheme is provided in the input url. So I've written a quick function to get the real host:

function getHost($Address) { 
   $parseUrl = parse_url(trim($Address)); 
   return trim($parseUrl['host'] ? $parseUrl['host'] : array_shift(explode('/', $parseUrl['path'], 2))); 
} 

getHost("example.com"); // Gives example.com 
getHost("http://example.com"); // Gives example.com 
getHost("www.example.com"); // Gives www.example.com 
getHost("http://example.com/xyz"); // Gives example.com 

function get_domain($url = SITE_URL)
{
    preg_match("/[a-z0-9\-]{1,63}\.[a-z\.]{2,6}$/", parse_url($url, PHP_URL_HOST), $_domain_tld);
    return $_domain_tld[0];
}

get_domain('http://www.cdl.gr'); //cdl.gr
get_domain('http://cdl.gr'); //cdl.gr
get_domain('http://www2.cdl.gr'); //cdl.gr

The code that was meant to work 100% didn't seem to cut it for me, I did patch the example a little but found code that wasn't helping and problems with it. so I changed it out to a couple of functions (to save asking for the list from Mozilla all the time, and removing the cache system). This has been tested against a set of 1000 URLs and seemed to work.

function domain($url)
{
    global $subtlds;
    $slds = "";
    $url = strtolower($url);

    $host = parse_url('http://'.$url,PHP_URL_HOST);

    preg_match("/[^\.\/]+\.[^\.\/]+$/", $host, $matches);
    foreach($subtlds as $sub){
        if (preg_match('/\.'.preg_quote($sub).'$/', $host, $xyz)){
            preg_match("/[^\.\/]+\.[^\.\/]+\.[^\.\/]+$/", $host, $matches);
        }
    }

    return @$matches[0];
}

function get_tlds() {
    $address = 'http://mxr.mozilla.org/mozilla-central/source/netwerk/dns/effective_tld_names.dat?raw=1';
    $content = file($address);
    foreach ($content as $num => $line) {
        $line = trim($line);
        if($line == '') continue;
        if(@substr($line[0], 0, 2) == '/') continue;
        $line = @preg_replace("/[^a-zA-Z0-9\.]/", '', $line);
        if($line == '') continue;  //$line = '.'.$line;
        if(@$line[0] == '.') $line = substr($line, 1);
        if(!strstr($line, '.')) continue;
        $subtlds[] = $line;
        //echo "{$num}: '{$line}'"; echo "<br>";
    }

    $subtlds = array_merge(array(
            'co.uk', 'me.uk', 'net.uk', 'org.uk', 'sch.uk', 'ac.uk', 
            'gov.uk', 'nhs.uk', 'police.uk', 'mod.uk', 'asn.au', 'com.au',
            'net.au', 'id.au', 'org.au', 'edu.au', 'gov.au', 'csiro.au'
        ), $subtlds);

    $subtlds = array_unique($subtlds);

    return $subtlds;    
}

Then use it like

$subtlds = get_tlds();
echo domain('www.example.com') //outputs: example.com
echo domain('www.example.uk.com') //outputs: example.uk.com
echo domain('www.example.fr') //outputs: example.fr

I know I should have turned this into a class, but didn't have time.

If you want extract host from string http://google.com/dhasjkdas/sadsdds/sdda/sdads.html, usage of parse_url() is acceptable solution for you.

But if you want extract domain or its parts, you need package that using Public Suffix List. Yes, you can use string functions arround parse_url(), but it will produce incorrect results sometimes.

I recomend TLDExtract for domain parsing, here is sample code that show diff:

$extract = new LayerShifter\TLDExtract\Extract();

# For 'http://google.com/dhasjkdas/sadsdds/sdda/sdads.html'

$url = 'http://google.com/dhasjkdas/sadsdds/sdda/sdads.html';

parse_url($url, PHP_URL_HOST); // will return google.com

$result = $extract->parse($url);
$result->getFullHost(); // will return 'google.com'
$result->getRegistrableDomain(); // will return 'google.com'
$result->getSuffix(); // will return 'com'

# For 'http://search.google.com/dhasjkdas/sadsdds/sdda/sdads.html'

$url = 'http://search.google.com/dhasjkdas/sadsdds/sdda/sdads.html';

parse_url($url, PHP_URL_HOST); // will return 'search.google.com'

$result = $extract->parse($url);
$result->getFullHost(); // will return 'search.google.com'
$result->getRegistrableDomain(); // will return 'google.com'