Nerdy New Year

Saturday, December 31, 2011

New Year’s resolutions come in all shapes and sizes; if you’re a web developer stuck for good ideas of things you could do to improve the world (or at least the tiny chunk of it that’s concerned with web performance and security) I’d like to propose two: secure user’s connections to all your websites, and use a cookieless domain for static assets.

SSL Everywhere.

If you look closely, you’ll notice that mikewest.org is being served via a secure connection: https rather than http. This is a Good Thing™, for reasons which I explored earlier this year. I’d like to suggest that each of you pop open Firefox (yes, Firefox) and head to StartSSL where you can, for free, create an account, verify your ownership of a domain, and generate an SSL certificate.

I’ve moved to StartSSL for every domain I own that hosts a website. It’s trivially easy, very well supported (I’ve never waited more than 18 hours for a response to a support request), and works well in every browser I care about. Moreover, it’s run by real people who you can email. I’ve gotten responses from the founder himself at two in the morning; the service is brilliant.

I’d suggest, actually, going through the extra step of verifying your identity with them so that you can generate wildcard certificates, and certificates with DNS alt names: both will make it easier for you to host SSL websites without the annoyance of setting up separate IP addresses for each host. They charge $59.90 for the verification, at which point you can create as many certificates as you like. It’s a heck of a deal.

And hey, while you’re at it, start serving Strict-Transport-Security headers too!

Cookieless domains for static assets

You’ve probably heard at some point in the past that it’s a good idea to serve static assets from a domain that doesn’t set cookies. Yesterday, I finally got around to doing that here. If you hop into devtools or Firebug, you’ll see that this page’s CSS, JavaScript, and images are all being served not from mikewest.org, but from mikewestdotorg.hasacdn.net. Setting up an alias like this is trivial in any server. Here’s how I made it work in Nginx:

My websites all have specific directories in which static assets live, /home/mkwst/public_html/mikewest.org/public/static for example. I simply set up a server listening for requests to mikewestdotorg.hasacdn.net, and use the static asset directory as the root. With that in place, I ensure that all files are served with far-future expiry headers, and then set up some trivial versioning magic by ignoring the first chunk of the URL: https://mikewestdotorg.hasacdn.net/20111231/style.css serves the same file as https://mikewestdotorg.hasacdn.net/1/style.css, but because the paths are different, the file can be loaded and cached anew when something changes.

That setup looks like this:

server {
  listen 80;
  server_name mikewestdotorg.hasacdn.net;

  # Turn off logging for static assets:
  access_log  off;
  error_log   /dev/null crit;

  # Set the root from which Nginx reads files for this domain:
  root /home/mkwst/public_html/mikewest.org/public/static;

  location / {
    add_header Expires "Thu, 31 Dec 2037 23:55:55 GMT";
    add_header Cache-Control "public, max-age=315360000";
    
    if (-f $request_filename) {
      break;
    }

    rewrite ^/\d+/(.*) /$1 break;
  }
}

Easy! I’ve thrown the whole config file up on GitHub if you’re curious.

So there you have it; enjoy the end of your holidays with these two resolutions that you can bang out over the weekend. You’ll be ahead of the game, and the envy of all your friends and neighbors when you compare notes at the end of 2012.

— Mike West