A Ruby wrapper for the Viralheat Sentiment Analysis API
see : http://viralheat.com/developer/sentiment_api
gem install sentiment_analysis
You can get an API key by visiting http://www.viralheat.com/developer. Sign up as a FREE developer and get a key for use with this gem. The developer dashboard will also show you details on your quota.
Simple way
require 'sentiment_analysis'
sa = SentimentAnalysis::Client.new(:api_key => '0123456789')
puts as.review(text: "i don't like this")
# => {"prob":0.732603741199471,"mood":"negative","text":"i don't like this"}
puts as.train(text: "I don't like coffee'", mood: 'negative')
# => {"status":"ok"}