ng-universal-https-www-on-gae-flex-solution.ts

//... start of the script
server.all(/.*/, function (req, res, next) {
  //
  // Get host
  const host: any = req.header('host');

  //
  // Skip localhost and IP requests
  if(host.includes('localhost') || host.match(/\b((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)(\.|$)){4}\b/)) {
    next();
  }

  //
  // redirect non www to www
  else if (!host.includes('www')) {
      res.redirect(301, 'https://www.' + host + req.url);
  }

  //
  // redirect http to https
  else if (req.header('x-forwarded-proto') && req.header('x-forwarded-proto') === 'http') {
      res.redirect(301, 'https://' + host + req.url);
  }

  // 
  // it's fine now
  else {
    next();
  }
}
//... end of the script