PHP Method for getting the middle part of a string

This is a substring between two substrings in a string, such as getting coderbolg substring from the string www. ofstack. com, let this PHP function to achieve it, the code is as follows:

function get_between($input, $start, $end) {
  $substr = substr($input, strlen($start)+strpos($input, $start),
 (strlen($input) - strpos($input, $end))*(-1));
  return $substr;
}
$string = "www.ofstack.com";
$start = "www.";
$end = ".net";
echo get_between($string, $start, $end);  // output:coderbolg

However, the limitation of this function is that the $start substring and the $end substring can only appear once in the whole string. Look at the following example:

$string = "https://www.ofstack.com/";
$start = "http://";
$end = "/";

Obviously, I want to get the domain name part of this standard URL. Because the $end substring is not only 1 in the whole string, there will be problems. Please pay attention when using it!