parse non encoded url - php

Question

there is an external page, that passes a URL using a param value, in the querystring. to my page.
eg: page.php?URL=http://www.domain2.com?foo=bar
i tried saving the param using
$url = $_GET['url']
the problem is the reffering page does not send it encoded. and therefore it recognizes anything trailing the "&" as the beginning of a new param.
i need a way to parse the url in a way that anything trailing the second "?" is part or the passed url and not the acctual querystring.

Answer 1

Get the full querystring and then take out the 'URL=' part of it
$name = http_build_query($_GET);
$name = substr($name, strlen('URL='));

Answer 2

Antonio's answer is probably best. A less elegant way would also work:
$url = $_GET['url'];
$keys = array_keys($_GET);
$i=1;
foreach($_GET as $value) {
$url .= '&'.$keys[$i].'='.$value;
$i++;
}
echo $url;

Answer 3

Something like this might help:
// The full request
$request_full = $_SERVER["REQUEST_URI"];
// Position of the first "?" inside $request_full
$pos_question_mark = strpos($request_full, '?');
// Position of the query itself
$pos_query = $pos_question_mark + 1;
// Extract the malformed query from $request_full
$request_query = substr($request_full, $pos_query);
// Look for patterns that might corrupt the query
if (preg_match('/([^=]+[=])([^\&]+)([\&]+.+)?/', $request_query, $matches)) {
// If a match is found...
if (isset($_GET[$matches[1]])) {
// ... get rid of the original match...
unset($_GET[$matches[1]]);
// ... and replace it with a URL encoded version.
$_GET[$matches[1]] = urlencode($matches[2]);
}
}

Answer 4

As you have hinted in your question, the encoding of the URL you get is not as you want it: a & will mark a new argument for the current URL, not the one in the url parameter. If the URL were encoded correctly, the & would have been escaped as %26.
But, OK, given that you know for sure that everything following url= is not escaped and should be part of that parameter's value, you could do this:
$url = preg_replace("/^.*?([?&]url=(.*?))?$/i", "$2", $_SERVER["REQUEST_URI"]);
So if for example the current URL is:
http://www.myhost.com/page.php?a=1&URL=http://www.domain2.com?foo=bar&test=12
Then the returned value is:
http://www.domain2.com?foo=bar&test=12
See it running on eval.in.