HTTP to HTTPS redirection on App Engine Flexible

The flexible environment does not current support handlers in the app.yaml. If you want https:// redirection, you have a few options:

• Use helmet to do to HSTS stuff for you, and implement your own initial redirect.
• I wrote a happy little library to always forces SSL on all routes for express yes-https

We are considering auto-redirecting all traffic to SSL by default. Do you think that would be a good thing for your apps?

Pulling Justin's yes-https library, I was able to get this to work:

var app = express();
app.use(function(req, res, next){
  if (req.host != 'localhost' && req.get('X-Forwarded-Proto') == 'http') {
    res.redirect(`https://${req.host}${req.url}`);
    return;
  }

  app.router(req, res, next);
});

At first I thought I had to do that since I was on an appengine subdomain and couldn't use HSTS. Then I learned HSTS works fine for subdomains. :) Regardless, I thought people might want to see what the magic bit to use was if they didn't want to use yes-https for some reason.

Justin, auto-redirecting all traffic to SSL by default sounds great to me. I just spent hours trying to figure out how to do so before I found this post because I was trying to get my app to get Chrome's add to homescreen install banner as per https://developers.google.com/web/fundamentals/engage-and-retain/app-install-banners/.