如何通过PHP检查Web服务器上是否存在ssl？

Question

I have this function in a class:

function enable_ssl() {
    if ($_SERVER[HTTPS] != "on") {
        $domain = "https://".$_SERVER['HTTP_HOST'] . "/" . $_SERVER['SCRIPT_NAME'];
        header("Location: {$domain}");
    }
}

The problem is that when the server doesn't have SSL installed and I have this function initiating the page redirects to a 404 page. I was wondering how I can have this function work only when SSL is installed and working?

Is it possible?

Thanks.

P.S.: I did some Google research but couldn't find much of anything.

Answer 1

On a *nix server, you could try parsing the output of netstat -A inet -lnp for a web server listening on port 443. Kinda clunky.

Better option, I'd say, is to make it a configuration option for the user. Let them tell your app if they've got HTTPS enabled.