PHP check if url is valid - php

Question

I wonder what would be the best way in php to check if provided url is valid... At first I tried with:
filter_var($url, FILTER_VALIDATE_URL) === false
But it does not accept www.example.com (without protocol). So I tried with a simple modification:
protected function checkReferrerUrl($url) {
if(strpos($url, '://') == false) {
$url = "http://".$url;
}
if(filter_var($url, FILTER_VALIDATE_URL) === false) {
return false;
}
return true;
}
Now it works fine with www.example.com but also accepts simple foo as it converts to http://foo. However though this is not a valid public url I think... so what would you suggest? Go back to traditional regexp?

Answer 1

I recommend, that you do not use filter_var with type URL.
There are much more side-effects.
For example, these are valid URLs according to filter_var:
http://example.com/"><script>alert(document.cookie)</script>
http://example.ee/sdsf"f
Additionally FILTER_VALIDATE_URL does not support internationalized domain names (IDN).
I recommend using a regex combined with some ifs afterwards (f.e. for the domain) for security reasons.
Without the security aspect I am using parse_url to take my parts. But this function has a similar issue, when the scheme (no http/https) is missing.

Answer 2

Use this
<?php
$url = 'www.example.com';
if(validateURL($url)){
echo "Valid";
}else{
echo "invalid";
}
function validateURL($URL) {
$pattern_1 = "/^(http|https|ftp):\/\/(([A-Z0-9][A-Z0-9_-]*)(\.[A-Z0-9][A-Z0-9_-]*)+.(com|org|net|dk|at|us|tv|info|uk|co.uk|biz|se)$)(:(\d+))?\/?/i";
$pattern_2 = "/^(www)((\.[A-Z0-9][A-Z0-9_-]*)+.(com|org|net|dk|at|us|tv|info|uk|co.uk|biz|se)$)(:(\d+))?\/?/i";
if(preg_match($pattern_1, $URL) || preg_match($pattern_2, $URL)){
return true;
} else{
return false;
}
}
?>
Try this one too
<?php
// Assign URL to $URL variable
$url = 'http://example.com';
// Check url using preg_match
if (preg_match("/^(https?:\/\/+[\w\-]+\.[\w\-]+)/i",$url)){
echo "Valid";
}else{
echo "invalid";
}
?>