Webpal is a web-based rewrite of the Palantir data viewer.
Webpal uses rudimentary bindings to GetData (see bindings.cc) for viewing the current state of binary data stored in a dirfile. A Node.js server uses a higher-level module to be notified of updates to watched fields, and streams the updates with socket.io to clients.
The build the low-level bindings run
$ node-waf configure build
If you have a dirfile, try playing with bindings_test.js
$ vi bindings_test.js
(Update the path_to_dirfile and field_name variables)
$ node bindings_test.js