验证URL PHP

Question

I've working on a project and in this project i need to check the user input is a valid URL.

I've made a preg_match for all possible characters used on a URL. However, I'm trying to make it show an error if HTTP:// / HTTPS:// is not in front of the URL.

Here is what I've done.

if(preg_match('/[^0-9a-zA-Z.\-\/:?&=#%_]/', $url) || substr($url, 0, 7) != "http://" || substr($url, 0, 8) != "https://") {

But that doesn't work. It keeps giving me the an OK message. I'm not sure what I'm doing wrong here, I hope I can get some help!

The if statement will return true or false. So

    if(preg_match('/[^0-9a-zA-Z.\-\/:?&=#%_]/', $url) || substr($url, 0, 7) != "http://" || substr($url, 0, 8) != "https://") {
echo "true";
} else {
echo "false";
}

I just need to check if the url has entered a valid url. I don't need to verify it. Just need to check if it has HTTP:// or HTTPS:// and contains valid URL characters.

Answer 1

Instead of a regex, you could make things easy on yourself and use the URL filtering in filter_var:

if (filter_var($url, FILTER_VALIDATE_URL)) { ...