Elasticsearch::FacetedSearch

gem 'elasticsearch-facetedsearch'

$ bundle

ELASTICSEARCH_INDEX = [
  Rails.env.development? && `whoami`.strip,
  Rails.env,
  Rails.application.class.to_s.split("::").first.downcase
].reject(&:blank?).join('_')

# Optional concepts to help with indexing / connection
ELASTICSEARCH_MODELS = []
ELASTICSEARCH_SERVER = 'http://lalaland.com:9200'

Elasticsearch::Model.client = Elasticsearch::Client.new({
  log: false,
  host: ELASTICSEARCH_SERVER,
  retry_on_failure: 5,
  reload_connections: true
})

# Good idea to prefilter the params with strong_params
#
def search
  @search = FruitFacetsSearch.new(params)

  # Fetch results
  # @search.results

  # Fetch facets
  # @search.facets
end

class FruitFacetsSearch
  include Elasticsearch::FacetedSearch::FacetBase

  # ... include other facet classes (examples below) ...
  include Elasticsearch::FacetedSearch::FacetColor

  # *required
  # The type to search for (Elasticsearch Type)
  # Can be an Array or String
  def type
    'fruit'
  end

  # Use this to add a query search or something
  # Probably best to cache the results
  def query
    @query ||= super
  end

  # Apply additional pre-filters
  # If overwriting this method, ensure to call super, and ensure to cache the results
  # => require color to be 'blue'
  def filter_query
    @filter_query ||= begin
      fq = super
      fq << { term: { color: 'blue' } }
      fq
    end
  end

  # Force specific limit or allow changable #s
  #
  def limit
    33
  end

  # Whitelisted collection of sortable options
  def sorts
    [
      {
        label: "Relevant",
        value: "relevant",
        search: [
          "_score"
        ],
        default: true
      }
    ]
  end

  # Want to always keep facet counts the same regardless of filters applied?
  # pass true to keep counts scoped to search, & false to remove filters entirely
  #
  def build_facets
    super(false)
  end
end

module Elasticsearch
  module FacetedSearch
    module FacetColor
      extend ActiveSupport::Concern

      included do
        # Adds the facet to the class.facets collection
        #
        # Available types:
        # => facet_multivalue
        # => facet_multivalue_and(:ident, 'elasticsearch_field', 'Human String')
        #     - Allows multiple values, but filters with :and execution
        # => facet_multivalue_or(:ident, 'elasticsearch_field', 'Human String')
        #     - Allows multiple values, but filters with :or execution
        # => facet_exclusive_or(:ident, 'elasticsearch_field', 'Human String')
        #     - Allows single value only
        #
        facet_multivalue_or(:color, 'color_field', 'Skin Color')
      end

      # *required
      # Should we apply the filter for this facet?
      # __Replace 'color' with the :ident value of your facet key
      def filter_color?
        valid_color?
      end

      # *required
      # Returns the array of selected values
      # __Replace 'color' with the :ident value of your facet key
      # __You should really take this time to whitelist the values and remove any noise. Elasticsearch can be picky if you're searching a number field and pass it an alpha character
      def color_value
        return unless valid_color?
        search_params[:color].split( operator_for(:color) )
      end

      # (optional)
      # By default, Elasticsearch only returns terms that are pertaining to the specific search. If a result was filtered out, that term would not show up.
      # Normally this isn't optimal... create this method and return an array of hashes with id and term keys.
      #
      # __Replace 'color' with the :ident value of your facet key
      def color_collection
        @color_collection ||= begin
          Color.all.map{|x| {id: x.id, term: x.name}}
        end
      end

      # (concept)
      # Use these type of helper methods to validate the information given to you by users
      #
      def valid_color?
        search_params[:color].present? && !!(search_params[:color] =~ /[\|[0-9]+]/)
      end
    end
  end
end

%ul
  -@search.facets.each do |group|
    %li.title=group.title
    -group.items.each do |item|
      - # Assuming you have some dynamic urls, you can use the url_for and merge in the params
      %li=item.link_to("#{item.term} (#{item.count})", url_for(params.merge(item.params_for)))

%ul
  -@search.results.each do |item|
    - # item is now direct reference to the elastic search _source
    - # item also contains item._type that displays the Elasticsearch type field
    %li=item.id