Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers.
...

error brings everything to a halt. Well on Centos the way to install the MySQL gem is:

$ sudo yum install mysql mysql-devel gcc
...
 
# 32 bit machine
$ sudo gem install mysql -- \
> --with-mysql-include=/usr/bin/mysql \
> --with-mysql-lib=/usr/lib/mysql
 
# or 64 bit like they are on SliceHost
$ sudo gem install mysql -- \
> --with-mysql-include=/usr/bin/mysql \
> --with-mysql-lib=/usr/lib64/mysq
 
Building native extensions.  This could take a while...
Successfully installed mysql-2.7
1 gem installed
...

We implemented QR Codes on BBC programmes (A project I’m one of the Software Engineer’s on, at the BBC) a few weeks back. They’ve been talked about since so I won’t repeat things, only to say it was a simple implementation using a JavaScript library by Kazuhiko Arase and took all of 5 minutes of my lunch hour to add. It started as an email by colleague Michael Smethhurst asking if we could/should implement them, and was also the first I had really heard of them.

Since then, I have done lots more research and think there is great mileage there for promotional material and advertising. At the moment the codes are built on the client side, but this will be moved to the server soon so we can start caching the pages, and also so we can provide the code in a more useful format (maybe images instead of the current HTML table).

So to the point of this post. During my research to understand QR Codes more and because of the lack of free readable spec (Anyone know if there is one?) I decided to reverse engineer the JavaScript library into a Ruby Gem as there didn’t seem to be one out there. This helped me understand the how QR Codes are encoded, while at the same time giving something back for other people to use.

You can find out more over at it’s project page on Github:
http://whomwah.github.com/rqrcode/

So that should get you going. Enjoy!