I recently ran into an issue where I needed the values from GET variables, but I did not know what the variables name was. The problem was related to the Facebook API. The API used PHP to get the current URL, but the current URL was rewritten using Apaches Mod Rewrite, making it an invalid URL (technically). To overcome this I needed a way to regenerate the URL of the page without knowing how many GET variables there were going to be and what they would be called. After a bit of messing around this is what I came up with.
E.G. You have a rewritten URL that looks like the following
http://example.net/page/123/345.html
This URL works with Apache, but it is not a proper URL that another website can understand without having the information to map the variable names.  The code snippet below will take a URL that you have rewritten using mod rewrite or any other method and output it as a URL with the GET variables present.
You will need to replace the name of the URL to the url of your website. If you run this on any page it will generate the full URL of your page.
http://example.net/page/123/345.html  =>   http://example.net/page.php?var1=123&var2=345
$filename = $_SERVER['PHP_SELF'];
$url = $filename;
if(isset($_GET))
{
$url = $url."?";
$counter = 0;
foreach($_GET as $var => $value)
{
if($counter != 0)
{
$url = $url."&";
}
$url = $url."&".$var."=".$value;
$counter ++;
}
}
$currentUrl = "http://example.net".$url;