[updated] Please Help. PHP.

[Orions]

<?php
$config["path"] = "";
$config["ext"] = ".php";

if (!isset($_REQUEST["page"])){
    $page = "main";
} else {
    $page = $_REQUEST["page"];
    $page = urldecode($page);
    $page = trim($page);
    $page = strip_tags($page);
    if (substr_count($page,"..") > 0 || substr_count($page,"~") > 0){
        $page = "main";
    }
}
$full = $config["path"] . $page . $config["ext"];
if (!is_file($full) || is_dir($full) || !file_exists($full)){
    die ("Sorry, the page you are looking for is gone. Please email the webmaster with the URL currently in your address bar so that it can be corrected. Thanks!");
} else {
    require_once($full);
}
?>

Can somebody please help me rescript this code, to allow for & functions to a similar nature to this:

<a href="index.php?page=home&file=article&sid=78">

This way it will allow for more flexibility when navigating my site, so that the links dont HAVE to reside on the index.php page, but can also be inside pages that are $_REQUEST'ed

[bugayev]

Its asking for main.php, not home.php if you don't pass any arguments.

[Orions]

Updated thread.