While building a facebook applicaiton that will be utilized across 100's of pages it was found a slight challenge to grab the current url dynamically...

First try:

function curPageURL() {
 $pageURL = 'http';
 if ($_SERVER["HTTPS"] == "on") {$pageURL .= "s";}
 $pageURL .= "://";
 if ($_SERVER["SERVER_PORT"] != "80") {
  $pageURL .= $_SERVER["SERVER_NAME"].":".$_SERVER["SERVER_PORT"].$_SERVER["REQUEST_URI"];
 } else {
  $pageURL .= $_SERVER["SERVER_NAME"].$_SERVER["REQUEST_URI"];
 }
 return $pageURL;
}
 
$currenturl = curPageURL();

A simple curl call was tried, however the server where the .php was was called not the facebook url

What worked:

<?php

$pageid = $_REQUEST['fb_sig_page_id'];

//grabs the current page id then use the current page id with the graph api

$jsonurl = file_get_contents("https://graph.facebook.com/" . $pageid);
$urlobj = json_decode($jsonurl);
$curUrl = $urlobj->{'link'};

print $curUrl;

?>

Hope this helps for anyone