OData Server
This is a rails plugin/engine to embue your application with OData features (so its data can be readily consumed by an OData client).
It was forked Mark Borkum’s work at from rubyforge.org/scm/?group_id=9605 with only a few small additions to support postgresql and declarative authorization and released as a gem.
The software iterates over your models exposing each as an OData source automatically.
Beware - this code is not heavily tested, it does work in my limited tests usint Tableau public to consume data.