VSS – Vector Space Search  

A simple vector space search engine with tf*idf ranking.

More info, and details of how it works.

Just install the gem:

gem install vss

Or add to your Gemfile, if you're using Bundler:

gem 'vss'

To perform a search on a collection of documents:

require "vss"
docs = ["hello", "goodbye", "hello and goodbye", "hello, hello!"]
engine = VSS::Engine.new(docs)
engine.search("hello") #=> ["hello", "hello, hello!", "hello and goodbye"]

If you want to search a collection of ActiveRecord objects, you need to pass a documentizer Proc when initializing VSS::Engine which will convert the objects into documents (which are simply strings). For example:

class Page < ActiveRecord::Base
    #attrs: title, content
end

docs = Page.all
documentizer = lambda { |record| record.title + " " + record.content }
engine = VSS::Engine.new(docs, documentizer)

This isn't designed to be used on huge collections of records. The original use case was for ranking a smallish set of ActiveRecord results obtained via a query (using SearchLogic). So, essentially, the search consisted of 2 stages; getting the corpus via a SQL query, then doing the VSS on that.

Tested with the following Ruby versions:

• MRI 1.9.2
• MRI 1.8.7

Probably works on JRuby ~> 1.6 too, but not actively tested.

Heavily inspired by Joesph Wilk's article on building a vector space search engine in Python.

Written by Mark Dodwell (@madeofcode)