iis_rewrite_fix.php

if (!isset($_SERVER['REQUEST_URI']))
{
    // IIS Mod-Rewrite
    if (isset($_SERVER['HTTP_X_ORIGINAL_URL'])) {
        $_SERVER['REQUEST_URI'] = $_SERVER['HTTP_X_ORIGINAL_URL'];
    }
    // IIS Isapi_Rewrite
    else if (isset($_SERVER['HTTP_X_REWRITE_URL'])) {
        $_SERVER['REQUEST_URI'] = $_SERVER['HTTP_X_REWRITE_URL'];
    } else {
        // Use ORIG_PATH_INFO if there is no PATH_INFO
        if ( !isset($_SERVER['PATH_INFO']) && isset($_SERVER['ORIG_PATH_INFO']) )
            $_SERVER['PATH_INFO'] = $_SERVER['ORIG_PATH_INFO'];

        // Some IIS + PHP configurations puts the script-name in the path-info (No need to append it twice)
        if ( isset($_SERVER['PATH_INFO']) ) {
            if ( $_SERVER['PATH_INFO'] == $_SERVER['SCRIPT_NAME'] )
                $_SERVER['REQUEST_URI'] = $_SERVER['PATH_INFO'];
            else
                $_SERVER['REQUEST_URI'] = $_SERVER['SCRIPT_NAME'] . $_SERVER['PATH_INFO'];
        }

        // Append the query string if it exists and isn't null
        if (isset($_SERVER['QUERY_STRING']) && !empty($_SERVER['QUERY_STRING'])) {
            $_SERVER['REQUEST_URI'] .= '?' . $_SERVER['QUERY_STRING'];
        }
    }
}