Preg-replace - replace all URLs except a domain and its subdomains - php

Question

I've a Glype proxy and I want not parse external URLs. All URLs on the page are automatically converted to: http://proxy.com/browse.php?u=[URL HERE]. Example: If I visit The Pirate Bay on my proxy, then I want not to parse the following URLs:
ByteLove.com (Not to: http://proxy.com/browse.php?u=http://bytelove.com&b=0)
BayFiles.com (Not to: http://proxy.com/browse.php?u=http://bayfiles.com&b=0)
BayIMG.com (Not to: http://proxy.com/browse.php?u=http://bayimg.com&b=0)
PasteBay.com (Not to: http://proxy.com/browse.php?u=http://pastebay.com&b=0)
Ipredator.com (Not to: http://proxy.com/browse.php?u=https://ipredator.se&b=0)
etc.
Of course I want to keep the internal URLs, so:
thepiratebay.se/browse (To: http://proxy.com/browse.php?u=http://thepiratebay.se/browse&b=0)
thepiratebay.se/top (To: http://proxy.com/browse.php?u=http://thepiratebay.se/top&b=0)
thepiratebay.se/recent (To: http://proxy.com/browse.php?u=http://thepiratebay.se/recent&b=0)
etc.
Is there a preg_replace to replace all URL's except thepiratebay.se and there subdomains (as in the example)? An other function is also welcome. (Such as domdocument, querypath, substr or strpos. Not str_replace because then I should define all URLs)
I've found something, but I'm not familiar with preg_replace:
$exclude = '.thepiratebay.se';
$pattern = '(https?\:\/\/.*?\..*?)(?=\s|$)';
$message= preg_replace("~(($exclude)?($pattern))~i", '$2$5$6', $message);

Answer 1

I'll guess you would need to provide a whitelist to tell which domains should be proxied:
$whitelist = array();
$whitelist[] = "internal1.se";
$whitelist[] = "internal2.no";
$whitelist[] = "internal3.com";
// and so on...
$string = 'External link 1<br>';
$string .= 'Internal link 1<br>';
$string .= 'Internal link 2<br>';
$string .= 'External link 2<br>';
//Assuming the URL always is inside '' or "" you can use this pattern:
$pattern = '#(https?://proxy\.org/browse\.php\?u=(https?[^&|\"|\']*)(&?[^&|\"|\']*))#i';
$string = preg_replace_callback($pattern, "my_callback", $string);
//I had only PHP 5.2 on my server, so I decided to use a callback function.
function my_callback($match) {
global $whitelist;
// set return bypass proxy URL
$returnstring = urldecode($match[2]);
foreach ($whitelist as $white) {
// check if URL matches whitelist
if (stripos($match[2], $white) > 0) {
$returnstring = $match[0];
break; } }
return $returnstring;
}
echo "NEW STRING[:\n" . $string . "\n]\n";

Answer 2

you can use preg_replace_callback() to execute a callback function for every match. In that function you can determine if the matched string should be converted or not.
<?php
$string = 'http://foobar.com/baz and http://example.org/bumm';
$pattern = '#(https?\:\/\/.*?\..*?)(?=\s|$)#i';
$string = preg_replace_callback($pattern, function($match) {
if (stripos($match[0], 'example.org/') !== false) {
// exclude all URLs containing example.org
return $match[0];
} else {
return 'http://proxy.com/?u=' . urlencode($match[0]);
}
}, $string);
echo $string, "\n";
(Example is using PHP 5.3 closure notation)