Is there a PHP function for retrieving the "first part" of a URL?

Question

Is there a PHP function for retrieving the "first part" of a URL, similar to how dirname/basename act on file paths?

Something along the lines of

echo "url_basename('example.com/this_post/12312')"

which would return

example.com

Answer 1

parse_url should do this reliably.

Answer 2

Here is the code to output example.com with your given URL:

$url = 'example.com/this_post/12312';

if (strpos($url,'http') === FALSE) {
    $url = 'http://'.$url;
}

$arrURLParts = parse_url($url);
$host = $arrURLParts['host'];
echo $host;

Warning: if you omit the part to ensure the URL starts with http then parse_url would return an empty host and put 'example.com/this_post/12312' into $arrURLParts['path'] instead.