Url validation with regex for old php version - php

Question

Note: I'm using an older PHP version so FILTER_VALIDATE_URL is not available at this time.
After many many searches I am still unable to find the exact answer that can cover all URL structure possibilities but at the end I'm gonna use this way:
I'm using the following function
1) Function to get proper scheme
function convertUrl ($url){
$pattern = '#^http[s]?://#i';
if(preg_match($pattern, $url) == 1) { // this url has proper scheme
return $url;
} else {
return 'http://' . $url;
}
}
2) Conditional to check if it is a URL or not
if (preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&##\/%?=~_|!:,.;]*[-a-z0-9+&##\/%=~_|]/i", $url)) {
echo "URL is valid";
}else {
echo "URL is invalid<br>";
}
Guess What!? It works so perfect for all of these possibilities:
$url = "google.com";
$url = "www.google.com";
$url = "http://google.com";
$url = "http://www.google.com";
$url = "https://google.com";
$url = "https://www.codgoogleekarate.com";
$url = "subdomain.google.com";
$url = "https://subdomain.google.com";
But still have this edge case
$url = "blahblahblahblah";
The function convertUrl($url) will convert this to $url = "http://blahblahblahblah";
then the regex will consider it as valid URL while it isn't!!
How can I edit it so that it won't pass a URL with this structure http://blahblahblahblah

Answer 1

If you want to validate internet url's, add a check for including a dot (.) character in your reg-ex.
Note: http://blahblahblah is a valid url as is http://localhost

Answer 2

Try this:
if (preg_match("/^(([\w]+:)?\/\/)?(([\d\w]|%[a-fA-f\d]{2,2})+(:([\d\w]|%[a-fA-f\d]{2,2})+)?#)?([\d\w][-\d\w]{0,253}[\d\w]\.)+[\w]{2,4}(:[\d]+)?(\/([-+_~.\d\w]|%[a-fA-f\d]{2,2})*)*(\?(&?([-+_~.\d\w]|%[a-fA-f\d]{2,2})=?)*)?(#([-+_~.\d\w]|%[a-fA-f\d]{2,2})*)?$/", $url)) {
echo "URL is valid";
}else {
echo "URL is invalid<br>";
}