James Smith

Well, I finally got round to it. I started developing The Carbon Diet 2 years ago (had the idea 3 years ago!), and it's finally spread it's wings and joined the world of open source.

After I'd been developing it for a few months, it became obvious that it was never going to be a commercial proposition, so it's been my intention to open it up for a very long time now. However, I was putting it off until "after I get it finished", or "after I tidy up the code", or any number of other reasons. Having a small child puts paid to all those plans, so I've finally bitten the bullet and released my dodgy code to the world as it is, warts and all.

The site is built in Rails, but it's pretty creaky. It was originally written in version 1.2 as I was learning, and a lot of the old-style controller and route code is still hanging around, waiting to be improved. I've started, but there is a long way to go to bring it up to a decent standard.

Anyway, if you use the site (or not!) and fancy improving it, now you can. Head on over to github to grab the code and join in. I hope to see you there!

I've been crazy busy for a while, but what little spare time I have grabbed here and there has been used investigating some areas of Rails I hadn't played with before, like route globbing and running without a database. The results are a couple of tools, one useful, one most definitely not.

The first (and most useful) is Has My Gem Built Yet?. I have a bunch of ruby gems on GitHub and get annoyed that I have to keep running "gem update" while waiting for GitHub to build the gem once I've pushed the code. Well, no more. Just put in the details, and the page checks for you and pops up a message when the gem is done. Nice. It got picked up on the GitHub blog, and I've even had some patches sent in. It's a nice feeling :)

The second app is somewhat less useful (though still entertaining). After a suggestion on Twitter by Tom Taylor, I built a website which lets you bookmark sandwich combinations. There are a couple of interesting bits in this though - first is route globbing, which is the Rails way of using arbitrary bits of the URL as parameters to an action. Not something you use in every project, but still. More importantly, I've used it to test out rubymarks, a Rails plugin for generating links for social bookmarking services.

I love Rails for this sort of thing. I can't think of other system I've used that would let me create such fun things in the tiny snippets of spare time I have at the moment. And of course, everything above is open source and available on Github.

So, the other day I got a nice little tray icon working for my CurrentCost power monitor. That's great, but data is only really gets fun when it's mashable, so the next step was to get it online somehow.

Pachube is a site which aggregates data feeds from real-world (and virtual-world) devices, shows them on a map, makes graphs, things like that, so it seemed like a good first attempt at putting my power data online. My first thought was to get my app to post data at regular intervals to the service, but unfortunately Pachube doesn't work like that. Instead, it acts more like a news reader, not a publishing platform - Google Reader instead of Blogger, if that makes sense. So, I had to publish my feed live on the web and point Pachube at the URL.

First step: EEML. This is an XML-based format which Pachube reads which can contain not only multiple data feeds, but tags and other metadata. So (as seems to be the fashion), I wrapped it up in a Ruby gem, available from GitHub as ever. The gem simply provides utility classes to build an EEML feed and convert it to the XML-based format for delivery over the web.

Then, the final step was to publish the data on the web. For that, we need a web server. However, having a full web server for just one feed seemed overkill, and I didn't want to publish to yet another intermediate server, so we need to serve the data directly. Ruby to the rescue once again. WEBrick is a simple web server which is part of the core Ruby libraries. You create a server, write simple servlet classes, and mount them at particular locations. For instance:

# Create WEBrick server
s = WEBrick::HTTPServer.new( :Port => 50000 )
# A simple "hello world" servlet 
class HelloServlet < WEBrick::HTTPServlet::AbstractServlet
  def do_GET(request, response)
    response.status = 200
    response['Content-Type'] = "text/xml"
    response.body = "hello world"
  end
end
s.mount("/", HelloServlet)

Now, http://localhost:50000/ will say "hello world". From here it's a simple modification to publish the EEML feed. EEML-Ruby includes a simple EEML server script as an example. So, after building this into the tray app, now whenever my CurrentCost is connected and the app is running, it serves up EEML data to the web. You can see the data feed (fairly intermittent, as obviously the meter isn't always connected to my PC at the moment) live on Pachube.

After a bit of work, I've finally got my CurrentCost meter working in Ruby, and I now have a power monitor sitting in my system tray! There were a few stages involved...

Serial comms: The ruby-serialport library that already existed for Ruby was no good to me. Firstly, it didn't seem to be in a working state, but more importantly, the license it is under (GPL) is no good to me. So, I had to write my own. I've created a nice simple serial library (including a gem) for Ruby called RB232, which is available on GitHub. It only supports reading at the moment, and only works on Linux systems, but it's a start. Next!

Reading CurrentCost data: Once RB232 was in place, this was pretty easy. Just create a couple of classes to wrap up the process of getting data from the meter, and away you go. Easy. Also released as a Ruby gem on Github.

User interface: Last step was to make a simple user interface for the meter, which you can see in the picture above. It's a simple tray icon that changes colour based on power usage. It's based heavily on another very useful tool called cctrayrb, so many thanks to Daniel Parnell for doing the heavy GUI lifting there. The app is included as part of the currentcost-ruby gem mentioned above.

Anyway, it's all freely available, so if you have a CurrentCost meter and a serial cable for it, you can grab the code and get going. Enjoy :)

JabberStatus was originally inspired by Twitter's facility to update your status via XMPP/Jabber. Unfortunately, Twitter's Jabber interface has been down for months now, which is rather sucky.

The solution to this? Extend JabberStatus to work for Twitter as well as Facebook. It turned out to be very easy, so it's online now. Just add twitterstatus@jabber.org to your contact list and it will talk you through the rest.

The JabberStatus code has moved to GitHub now, so you can grab it from there. The code for the CO2Updates app has also moved there.