Carlo Pecchia

A glimpse to Solr (with Rails, of course!)

I’ve recently published an article for the italian webzine HTML.it on using Solr within a Rails application.

Basically Solr is a search engine that you can “embed” in your Rails application through a nice plugin acts_as_solr.

After installing the plugin, and started the solr server (rake solr:start) you should define what model in your app fall under solr control and on which fields.

Let’s see some (simple) code.

class Recipe < ActiveRecord::Base
  has_and_belongs_to_many :tags
  has_and_belongs_to_many :ingredients

  validates_presence_of :name
  validates_presence_of :description
  validates_presence_of :preparation_time

  acts_as_solr  :fields => [:name, :description],
				:include => [:ingredients, :tags]
end

Now we are able to find recipe objects with Solr facility:

results = Recipe.find_by_solr('tomato')
recipes_related_to_tomato = results.docs

Simple, isn’t it?

Of course things can go more exciting:

results = Recipe.multi_solr_search('tomato OR apple',
				:models => [Tag, Ingredient])
objects_related_to_tomato_or_apple = results.docs

Finally, don’t forget to rebuild your Solr indexes when appropriate:

Recipe.rebuild_solr_index

Happy searching! ;)