I want to use Apache Mahout in my project on Ruby on Rails for implementing recommendations and collaborative filtering. In Particular my requirements are:
For what it's worth, the Mahout 'taste-web' module contains scripts that will build a ready-to-use web service around a Java-based Recommender, as a .war file that you can deploy on something like Tomcat, and then talk to via HTTP. That would be accessible from any platform that can make HTTP requests.
http://lucene.apache.org/mahout/taste.html#Standalone+server