PHP filter_input验证并清理

Question

I'm coding a contact form and I want to validate and sanitize user input using filter_input The problem is that because I use it for every POST variable shall I do a validate then sanitize or what? my suggestion is as follows:

if (!filter_input(INPUT_POST, 'email', FILTER_VALIDATE_EMAIL)) {
exit ();
} else {
$email  = $_POST['email'];
}

is this OK or I must re-sanitize the $_POST['email']

Thanks

Answer 1

Try this:

if ( !$email = filter_input(INPUT_POST, 'email', FILTER_VALIDATE_EMAIL)) {
    exit();
}

echo $email