Content-Type:    application/octet-stream    
...
Content-length:    56144    
Content-Disposition:    inline; filename="wingadget-rss.gadget";    
Content-transfer-encoding:    binary

<?php
if ( ($_GET["name"]) && (strpos($_GET["name"], ".gadget") ) )
{
    try
    {
        $readFile = "";
        $openFile = fopen ("your\url\to\content\folder\".$_GET["name"],"r");
        if($openFile)
        {        
            while(!feof($openFile))
            {
                $readFile  .= fread($openFile, 4096);
            }
            fclose($openFile);
            header("Content-Type: application/octet-stream; ");
            header("Content-Transfer-Encoding: binary");
            echo $readFile;
        }
    }
    catch (Exception $e)
    {
        echo "Sorry";
    }
}
else
{
    echo "Sorry";
}
?>