URL shorteners are the bane of the internet. However, for those of us who use Twitter on a regular basis, you know that 140 characters can be limiting. URLs can theoretically be 2,000 characters or more, but most are in the 40 to 80 character range. That's almost half your tweet! So we use URL shorteners to not only shorten the URLs, but (in the case of some services like Bit.ly) to track clicks and get statistics about who clicked on these short URLs.

The problem, however, with the popular URL services is that the more that they are used, the longer their URLs get. Both Bit.ly and Tiny.cc are up to 6 characters in their autogenerated URL paths. Add in the URL protocol (http://), the hostname (bit.ly) and the initial slash, and you've got minimum 20 character URLs.

So why use someone else's short URL service, when you can create your own, branded, shorter short URL service with URLs like lb.cm/a or jen.cm/j? A branded URL shortener can also be a sign of prestige or add a layer of trust. For instance, Flickr's URL shortener, flic.kr only links to Flickr photos. When you click on a flic.kr URL, you know what you're going to get. Google has a similar service with goo.gl and WordPress has recently launched wp.me. Even if you open it up for the public to use, as we have with lb.cm, there's just a certain geek prestige in having your own URL shortener.

Why Drupal?

So why use Drupal as a URL shortener? There are several single-purpose stand-alone Open Source URL shorteners out there already. And Drupal is sometimes criticized as being big and slow. URL shorteners need to be small and fast. On the other hand, we're not really expecting bit.ly-level traffic here, are we? Maybe we can consider Drupal.

So what do we get out of using Drupal as a URL shortener?

• User management - Bang! You've got users with accounts and passwords and permissions.
• Views support - Provide a nice listing for users of the URL's they've created
• Security - We can build on top of Drupal's existing security around database requests, user permissions, and
• Internationalization - A localized URL shortener? A multilingual URL shortener? It's all built-in to Drupal.
• Hooks - Drupal's hook system is what allows you to build modules. By using hook_boot() for a URL shortener module, we can get in before Drupal bootstraps most of its code. This essentially trims some of Drupal's fat and allows us to do just a single database query to try to load a given short URL. If it exists, "bingo!" we can redirect the user without invoking a complete Drupal boostrap.

And what if our URL shortener does become super-popular? Well then we'd probably start doing some cool tricks with Memcache, maybe a little Varnish, and probably adjust our .htaccess file so that Drupal would never get touched when an existing short URL is requested. All of the Drupal goodness without any of the Drupal bloat!

Building our URL Shortener: lb.cm

I've been using bit.ly for several years and I really like it. My goal was to build something with a similar feature set including:

• choice of custom (create-your-own) or auto-generated URLs
• click tracking
• user-owned short URLs
• a web services API for shortening and expanding URLs
• case-sensitive URLs (more characters in less space = shorter URLs)
• click-to-copy-to-clipboard link on resulting short URLs
• the ability to alias multiple domains to the same redirects (bit.ly and j.mp)
• a javascript bookmarklet to autofill a page's URL
• role-based rate limiting to prevent anonymous overuse of the API, conversely to allow special users unlimited use of the API

I also wanted

• the ability to add special character Unicode (UTF8) URLs
• Views support to allow admins to create custom listings

The funny thing about a dedicated URL shortening site is that it doesn't really use nodes! On our site, there's currently only one published node, the about page. The rest of it is just blocks and pages from the ShURLy module.

ShURLy Module

My initial research turned up the Shorten URLs / Short URL combo of modules. Shorten URLs is an abstracted module for using the web services APIs of sites like bit.ly, is.gd, tinyurl.com, etc., to create short URLs using the Drupal interface. Short URL is an API add-on to Shorten URLs which allows you to turn your own site into a URL shortener. I gave them a once over and found the user interface to be confusing with lots of options for things I didn't need and lacking in most of the features which I was looking for. Perhaps most importantly, upon inspecting the way that they were storing their information in the database, I couldn't figure out a way to provide the features I was looking for and also give administrators an upgrade path.

So I decided to start from scratch and create my own module. It's been a while since I've done a from-scratch module and I thought it would be fun. And it was! The result is ShURLy, a module which is now available on drupal.org. It implements all of the features I was looking for. It's really easy to set up and it's got what I hope is a pretty self-explanatory user interface. Download it and check it out for yourself. I'd like to know what people think.

The End Result

The real project here was to create a site, not a module. So that's what we did! The end result can be seen at http://lb.cm. It's open to the public for anyone to use. Anonymous users can create auto-generated short URLs. But if you want to really see the beauty of it, create an account for yourself and you'll be able to see your URL history, get click tracking, and create your own custom URLs. You can even create unicode URLs like http://lb.cm/♥, http://lb.cm/✌, or http://lb.cm/¡ǝɯosǝʍɐ-sı-sıɥʇ.

It's about as simple a Drupal site as you're going to see. It's mostly just ShURLy and a really nice theme design by Lullabot's superstar designer, Jared Ponchot. Once you're logged in, you'll get to see Views in action showing your URL history in a block at the bottom of the page. Views also provides the admin page listing history for all users.

The site also has web services, courtesy of ShURLy, and you can find documentation for them here. Jerad Bitner has already created (the beginnings of) a module called ShurlyBot to allow users to create short URLs in an IRC channel using Drupal's Bot module.

This was definitely one of those weekend-fun-turned-actually-useful projects. A URL shortener is a great example of something that seems simple until you really start digging into it. But now that it's done, we're happy to have lb.cm, and we're happy to contribute ShURLy back to the Drupal community.