$parsedUrl = parse_url($uri);
// if the uri has no scheme, it won't think there's a host and will give bad results
if ($parsedUrl !== false && !isset($parsedUrl['host'])) {
  // double slash prepended will parse $uri as if it has a schema and no schema will be in the result
  $parsedUrl = parse_url('//' . $uri);
}
if ($parsedUrl === false) {
  throw new MalformedUrlException('Malformed URL: ' . $uri);
}
// use parsed url as needed