[PHP] – Valid URL Checking

To keep it short and sweet today, the following is a PHP function that will check the input for a valid URL, and will also check to see if it is responding (ie: returning Status: 200 OK).

UPDATES:

• December 01, 2024: Slight updates to code style and more “modern” PHP features (i.e.: PHP 7.4+). Also added an important note.

Note: This only checks if a given URL returns certain HTTP response/status codes. It considers a valid URL one that returns 200 OK, 301 Moved Permanently, or 302 Found.

With that being said, the function can be found below.

function isValidUrl(string $url): bool
{
	if (!($url = @parse_url($url))) {
		return false;
	}

	$url['port'] ??= 80;
	$url['path'] = (!empty($url['path'])) ? $url['path'] : '/';
	$url['path'] .= (isset($url['query'])) ? "?$url[query]" : '';

	if (isset($url['host']) && $url['host'] !== @gethostbyname($url['host'])) {
		$headers = get_headers(\sprintf('%s://%s:%d%s', $url['scheme'], $url['host'], $url['port'], $url['path']));

		return (bool) preg_match('#^HTTP/.*\s+[(200|301|302)]+\s#i', $headers[0]);
	}
	return false;
}

How to use it? It’s simple.

if (isValidUrl('http://google.com')) {
	echo 'sweetness!';
} else {
	echo 'awww damn';
}

Enjoy 🙂