Automatic HTTPS connection/redirect with node.js/express

Thanks to this guy: https://www.tonyerwin.com/2014/09/redirecting-http-to-https-with-nodejs.html

If secure, requests via https, otherwise redirects to https

app.enable('trust proxy')
app.use((req, res, next) => {
    req.secure ? next() : res.redirect('https://' + req.headers.host + req.url)
})

Ryan, thanks for pointing me in the right direction. I fleshed out your answer (2nd paragraph) a little bit with some code and it works. In this scenario these code snippets are put in my express app:

// set up plain http server
var http = express();

// set up a route to redirect http to https
http.get('*', function(req, res) {  
    res.redirect('https://' + req.headers.host + req.url);

    // Or, if you don't want to automatically detect the domain name from the request header, you can hard code it:
    // res.redirect('https://example.com' + req.url);
})

// have it listen on 8080
http.listen(8080);

The https express server listens ATM on 3000. I set up these iptables rules so that node doesn't have to run as root:

iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 80 -j REDIRECT --to-port 8080
iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 443 -j REDIRECT --to-port 3000

All together, this works exactly as I wanted it to.

To prevent theft of cookies over HTTP, see this answer (from the comments) or use this code:

const session = require('cookie-session');
app.use(
  session({
    secret: "some secret",
    httpOnly: true,  // Don't let browser javascript access cookies.
    secure: true, // Only use cookies over https.
  })
);