Indices

Model search indices with elasticsearch in rails.

Why

I did this gem to:

• Gain control of the queries without losing simplicity.
• Have out of the box integration with activerecord and pagers.
• Deal with the just in time nature of elasticsearch.
• Integrate activerecord tool on it.
• Have a convention of how to integrate suggestions.

Install

Put this line in your Gemfile:

gem 'indices'

Then bundle:

$ bundle

To install Redis you can use homebrew:

brew install elasticsearch24

NOTE: This gem is tested agains version 2.4.

Configuration

Generate the configuration file:

bundle exec rails g indices:install

Configure the global settings:

Indices.configure do |config|

  config.hosts = %w(localhost:9200)
  config.log = false
  config.trace = false

  config.mappings do
    name do
      type 'string'
      fields do
        raw do
          type 'string'
          index 'not_analyzed'
        end
      end
    end
    category type: 'string'
    price type: 'long'
    currency type: 'string'
    product_suggestions do
      type 'completion'
      analyzer 'simple'
    end
  end

  config.analysis do
    filter do
      ngram do
        type 'nGram'
        min_gram 2
        max_gram 20
      end
    end
  end

  config.suggestions do |name, term, options={}|
    type = name.to_s.singularize
    text (term || '')
    completion do
      field "#{type}_suggestions"
    end
  end

  config.add_computed_sort :price do |direction|
    _script do
      type 'number'
      script do
        inline "if (_source.currency == 'UYU') { doc['price'].value * 30 }"
      end
      order direction
    end
  end

end

Generate an index:

bundle exec rails g indices:index products

Configure the index:

Indices.define :products do

  mappings do
    properties :name, :category, :price, :product_suggestions
  end

  serializer do |record|
    set record, :name, :category, :price
    product_suggestions do
      input [record.name, transliterate(record.name)].uniq
      output record.name
    end
  end

  search do |*args|
    options = args.extract_options!
    term = args.first
    query do
      if term.present?
        multi_match do
          query term
          type 'phrase_prefix'
          fields %w(name category)
        end
      else
        match_all
      end
    end
  end

end

Usage

Indexing

Ocurrs everytime you create or destroy a record:

product = Product.create(name: 'Les Paul', category: 'Gibson')

You can force it manually by:

product.index
product.reindex
product.unindex

At any time you can force a full rebuild:

bundle exec rake indices:rebuild

Or if you need it, just a build:

bundle exec rake indices:build

Search

The search parameters are sent to previous configured block:

@products = Product.search(name: 'Test')

You can use the returned value as a collection in views:

<%= render @products %>

Includes

Same as using activerecord relations:

Product.search(includes: :shop)

With / Without

You can force a record to be part of the results by id:

Product.search(with: 4)

Or the opposite:

Product.search(without: 4)

Pagination

Works the same as Pagers gem:

@products.page 1, padding: 4, length: 30

And you can send the collection directly to the helper in views:

<%= paginate @products %>

Order

Works the same as in relations:

@products.order(name: :asc)

To use a computed_sort:

@products.order(price: :asc)

NOTE: To sort by a string column, you must declare the mapping raw.

Suggestions

The suggestion parameters are sent to previous configured block:

Indices.suggest :products, 'gibson'

Returns array of hashes with a text property:

[{ text: 'Les Paul' }, ...]

Credits

This gem is maintained and funded by mmontossi.

License

It is free software, and may be redistributed under the terms specified in the MIT-LICENSE file.