Roommate bill splitter.
Screenshot: http://i.imgur.com/jukaf.png
The front-end is a single-page app written in LiveScript, using the bootstrap framework. Any change to the page is immediately saved to the back-end, and it is possible to navigate back in time to an arbitrary version of the data.
- Edit src/main.ls. You might be interested in changing
backend-url,namesandmonth-names. - Run
make. - Copy www/ to your server.
For the back-end I wrote a simple HTTP server in Haskell (inspired by rephttpd). Initially I used CouchDB to persist the data but since I was unable to install the couchdb cabal package on Debian 6, I eventually replaced it with my own database.
The database (see LastDB.hs) is a ridiculously simple append-only key-value store. Each entry is a line in a file. Newlines are not supported in an entry, which is not a problem as I'm only storing JSON-serialized items. The key to each entry is the offset in the file to end of that line, and each read operation returns the key to the previous line.
As such, all operations (getThing, getLastThing, appendThing) run in constant time w.r.t the number of items in the database.
- Edit the HTTP port in
Httpd.hs, and the database file inLastDB.hs. cabal install~/.cabal/bin/contas