How to Do Unit Conversion

I just set up a web service (link to a demo) to convert units and spit out json. The source is given below:

Some notes on the code, it spits out JSON in an uncompressed, non-pretty-printed format. It calls the units application to do the conversion. If I were so inclined, I'd have it access this through its shared library with cython, but this was quick and dirty, taking me all of 10 minutes.