stripping altered URLs from strings with preg_replace() - php

Question

As the title says, but the regex i am using has some glitches. im not too good with regex, as you can see
I am trying to remove any web URLs that a user adds to a string.
However, as the user is "crafty", they try to alter the URL slightly so that it does not trigger my removal code, hence my below regex will match on slightly modified urls too (hence me not using a conventional ULR regex). I know it will always be possible to trick my removal code, but i would like to make it as hard as possible
The problem i am having is if a user adds a sentence and then a full stop, but does not space out things right, the below regex matches this. i would like to limit this as best possible.
e.g all the below match:
this.matches (i dont want this to match).
mysite.co.xx (i want this to match).
http:// www.mysite.co.xx (i want this to match)
i am trying to limit the characters after the last "." to between 2 and 4 but am struggling to work out how to do this.
The code below is what i am using.
define('REG_URL', '#((https?://|https?://\s)?([-\w]+\.[-\w\.]+)+\w(:\d+)?(/([-\w/_\.]*(\?\S+)?)?)*)#');
public function stripURLs($string){
try {
$replacement = "[** website removed **]";
$string = preg_replace(REG_URL, $replacement, $string);
return $string;
}
catch (Exception $e){
error_log('checksubmitted.class.php MLE_Check.stripURls - Exception caught: '.$e->getMessage());
return false;
}
}
if anyone could point me in the right direction for how i do what i want, i would be very grateful.
If anyone know of any similar questions on here (i cant find any) or any other site that offers advice on removing "crafty" URLs i would again be grateful if this could be pointed out to me.

Answer 1

This is my personal preference for validating urls:
_^(?:(?:https?|ftp)://)(?:\S+(?::\S*)?#)?(?:(?!10(?:\.\d{1,3}){3})(?!127(?:\.\d{1,3}){3})(?!169\.254(?:\.\d{1,3}){2})(?!192\.168(?:\.\d{1,3}){2})(?!172\.(?:1[6-9]|2\d|3[0-1])(?:\.\d{1,3}){2})(?:[1-9]\d?|1\d\d|2[01]\d|22[0-3])(?:\.(?:1?\d{1,2}|2[0-4]\d|25[0-5])){2}(?:\.(?:[1-9]\d?|1\d\d|2[0-4]\d|25[0-4]))|(?:(?:[a-z\x{00a1}-\x{ffff}0-9]+-?)*[a-z\x{00a1}-\x{ffff}0-9]+)(?:\.(?:[a-z\x{00a1}-\x{ffff}0-9]+-?)*[a-z\x{00a1}-\x{ffff}0-9]+)*(?:\.(?:[a-z\x{00a1}-\x{ffff}]{2,})))(?::\d{2,5})?(?:/[^\s]*)?$_iuS