301 Redirect with Express

If you've created a site using Node.js, there's a great chance you've used the Express framework.  Express has turned into a massive project and for good reason:  it's loaded with useful functionality, an easy API, and massive community support.  On of my recent projects was using Express and I loved it!

One problem I recently needed to solve was creating a 301 redirect from an old staging domain to the new production domain.  Here's how you can create that 301 redirect with Express:

app.use(function forceLiveDomain(req, res, next) {
  // Don't allow user to hit Heroku now that we have a domain
  var host = req.get('Host');
  if (host === 'serviceworker-cookbook.herokuapp.com') {
    return res.redirect(301, 'https://serviceworke.rs/' + req.originalUrl);
  }
  return next();
});

Surprisingly the redirect code is the first argument to redirect instead of the URL.  It's important to call next() at the end of the function or a non-match will make your app hang!