Redis::TextSearch - Use Redis to perform text search from any type of class

This gem implements an extremely fast text search using Redis, based on the patterns from James Gray’s lists and sets in Redis post as well as Antirez’s text search gist. You can use it with any type of class, whether it be ActiveRecord, DataMapper, MongoRecord, or even a class having nothing to do with an ORM.

This is not intended to be the most full-featured text search available. For that, look into Sphinx, Solr, or other alternatives. This gem is designed to (a) be extremely fast and (b) handle any (or multiple) data stores.

The only requirement this gem has is that your class must provide an id instance method which returns the ID for that instance. ActiveRecord, DataMapper, and MongoRecord all have id methods which are known to be suitable. Since “ID” can be any data type, you can even write an id method of your own that just returns a string, or an MD5 of a filename, or something else unique.

Installation

gem install redis-textsearch

Initialization

If you’re using Rails, config/initializers/redis.rb is a good place for this:

require 'redis'
require 'redis/text_search'
Redis::TextSearch.redis = Redis.new(:host => 'localhost', :port => 6379)

Example

Model class:

class Post < ActiveRecord::Base
  include Redis::TextSearch

  text_index :title, :minlength => 2
  text_index :tags, :exact => true
  text_index :description, :full => true  # allow full-phrase "Search With Spaces"

  # Using AR callback (you can call update_text_indexes anywhere on your instance)
  after_save do |r|
    r.update_text_indexes
  end
  after_destroy do |r|
    r.delete_text_indexes
  end
end

Create posts:

Post.create(:title => "All About Bacon", :tags => "chef nontechnical")
Post.create(:title => "All About Bacon - Part 2", :tags => "chef nontechnical")
Post.create(:title => "Homemade Belgian Waffles", :tags => "chef nontechnical")
Post.create(:title => "Using Redis with Ruby", :tags => "technical ruby redis")
Post.create(:title => "Installing Redis on Linux", :tags => "technical redis linux")
Post.create(:title => "Chef Deployment Recipes", :tags => "ruby howto chef")

Then search for them:

@posts = Post.text_search('bacon')   # 2 results
@posts = Post.text_search('chef')    # 4 results (tags and title)
@posts = Post.text_search('technical', 'ruby')   # AND search (1 result)
@posts = Post.text_search('chef', :fields => :tags)   # 3 results (only search tags)

You can pass options through to the find method:

@posts = Post.text_search('redis', :order => 'updated_at desc')
@posts = Post.text_search('redis', :select => 'id,title', :limit => 50)

And do pagination (adapted from will_paginate):

@posts = Post.text_search('redis', :page => 1, :per_page => 10)
@posts = Post.text_search('redis', :page => 1)  # uses class.per_page like will_paginate

You can also specify specific fields to search as a hash:

@posts = Post.text_search(:tags => 'chef')  # 4 results
@posts = Post.text_search(:tags => ['technical','ruby'])  # AND (1 result)
@posts = Post.text_search(:tags => 'redis', :title => 'linux')  # 1 result
@posts = Post.text_search(:title => 'chef') # 1 result

Note that if you need to pass options to find AND search specific fields, the first hash must be in brackets:

@posts = Post.text_search({:tags => 'chef', :title => 'deployment'},
                          :order => 'updated_at desc')

Redis::TextSearch - Use Redis to perform text search from any type of class

Installation

Initialization

Example

Author