Solr Abstraction

solr.rb

module Morpheus
  module Adapters
    module Solr
        class Relation
          include ActiveModel::Model
          attr_accessor :connection, :relation_class, :where

          delegate :present?, :blank?, :empty?, to: :to_a
          delegate :each, :map, :collect, :select, :find, :last, :first, to: :to_a
          delegate :total, :facet_fields, to: :response

          # @api public
          #
          # Define the rows size to pass to Solr.
          #
          # @param per_page_number the page number that will be calculated to pass in the start Solr option.
          #
          # @example
          #
          #     Relation.new.per_page(50)
          #     Relation.new.limit(100)
          #
          def per_page(per_page_number)
            @per_page = per_page_number
            self
          end
          alias :limit :per_page

          # @api public
          #
          # Define the page number to pass to Solr.
          #
          # @param page_number the string that will pass to solr.
          #
          # @example
          #
          #     Relation.new.page('2')
          #
          def page(page_number)
            @page = page_number
            self
          end

          # @api public
          #
          # Define the order column to pass to Solr.
          #
          # @param order_by the string that will pass to solr.
          #
          # @example
          #
          #     Relation.new.order('')
          #
          def order(order_by)
            @order = order_by
            self
          end

          # @api public
          #
          # Define the field query param to send to Solr.
          #
          # @param field_query the exact field query, that will be send in params.
          #
          # @example
          #
          #     Relation.new.filter(name: 'Saraiva')
          #
          def filter(field_query)
            @filter = field_query
            self
          end

          # @api public
          #
          # Change the records parser, to only parse by the FacetResponseHandler.
          #
          def facets
            @facets = true
            self
          end

          # @api public
          #
          # Returns the start param to send to Solr.
          #
          # @example
          #
          #     Relation.new.start
          #
          def start
            if @per_page.present? and @page.present?
              @per_page.to_i * (@page.to_i - 1)
            end
          end

          # @api public
          #
          # Returns the total description and the actual records from this current page.
          #
          # <b>The per page default is 50 and the page default is 1.</b>
          #
          # @example
          #
          #     Relation.new(connection: connection, relation_class: Solr::Category).page(2).total_description
          #
          # def total_description
          #   limit_number = @per_page || 25
          #   page_number  = @page || 1
          #   initial      = start.to_i + 1
          #   final        = limit_number.to_i * page_number.to_i
          #   final        = total if final > total
          #
          #   I18n.t('admin.navigation.total_description', initial: initial, final: final, total: total)
          # end

          # @api public
          #
          # Make the solr request and setup the document collection to relation object
          #
          # @return <Array>
          #
          # @example
          #
          #     Relation.new(connection: connection, relation_class: Solr::Category).to_a
          #
          def to_a
            return collection if collection.present?

            response.records.each { |record| collection.push(record) }

            collection
          rescue RuntimeError, RSolr::Error::Http => exception
            Rails.logger.error exception.message
            collection
          end

          # @api public
          #
          # Returns the proxy object that wraps the response from Solr, passing the relation class.
          # See Solr::ResponseHandler for more information.
          #
          def response
            @response ||= if @facets.present?
              Solr::FacetResponseHandler.new(relation_class, response: response_body)
            else
              Solr::ResponseHandler.new(relation_class, response: response_body)
            end
          end

          # @api public
          #
          # Returns the Solr Raw response for wt ruby.
          #
          # <b>You need to pass a connection that responds to #get method.</b>
          #
          def response_body
            Rails.logger.info("\e[36m  #{relation_class} Load #{connection.base_uri.path} \e\[0m \e[01m#{params}\e[0m")
            connection.get('select', params: params)
          end

          # @api public
          #
          # Returns all collection array from solr.
          #
          def collection
            @collection ||= []
          end

          def inspect
            "#<Solr::Relation #{to_a}>"
          end

          # @api private
          #
          # Returns all params to send to Solr remove all blank values.
          #
          def params
            {
              q:     Solr::WhereNode.new(self.where),
              rows:  @per_page,
              start: start,
              sort:  @order,
              fq:    Solr::WhereNode.new(@filter)
            }.delete_if { |key, value| value.blank? }
          end

          # Create this alias just to be ActiveRecord like.
          #
          # @example
          #
          #    Solr::Relation.new(where: 'name_pt:Saraiva').explain
          #
          alias :explain :params
        end
      end

      class WhereNode < String
        # @param node can be a String or a Hash
        #
        def initialize(node)
          @node = node

          super(build.to_s)
        end

        # Build 'q' param to send to Solr.
        #
        # @example
        #
        #   # With String
        #   Solr::WhereNode.new('name_pt:"Saraiva"')
        #   # => 'name_pt:"Saraiva"'
        #
        #   # With Hash
        #   Solr::WhereNode.new(name_pt: "Saraiva")
        #   # => 'name_pt:"Saraiva"'
        #
        #   # With Hash with many fields
        #   Solr::WhereNode.new(name_pt: 'Saraiva', status: true)
        #   # => '(name_pt:"Saraiva") AND (status:true)'
        #
        #   # With value as Array
        #   Solr::WhereNode.new(id: [1, 2, 3, 4])
        #   # => 'id:(1 OR 2 OR 3 OR 4)'
        #
        def build
          return @node if @node.is_a?(String) or @node.blank?

          @nodes = @node.collect.each { |key, value| build_criteria(key, value) }

          if @nodes.size > 1
            @nodes.map! { |node| "(#{node})" }.join(' AND ')
          else
            @nodes.join()
          end
        end

        def build_criteria(key, value)
          formatted_value = if value.is_a?(Array)
            "(#{Array(value).join(' OR ')})"
          else
            build_value(value)
          end

          "#{key}:#{formatted_value}"
        end

        def build_value(value)
          value == '*' ? value : %{"#{value}"}
        end
      end

      class Base
        include Virtus
        extend ActiveModel::Naming
        extend ActiveModel::Translation

        def category_path(categories)
          Array(categories.find { |category| category.id.to_i == category_id.to_i }.try(:parent_path))
        end

        class << self
          attr_accessor :resource_name

          def connection
            RSolr.connect(
              url:               "#{Settings.solr.url}/#{resource_name}",
              read_timeout:      Settings.solr.read_timeout,
              open_timeout:      Settings.solr.open_timeout,
              retry_503:         Settings.solr.retry_503,
              retry_after_limit: Settings.solr.retry_after_limit
            )
          end

          # @api public
          #
          # Set the resource name that will be search in Solr Request.
          #
          # @example
          #
          #      class MyClass < Solr::Base
          #        # Will search by solr_url/my_class
          #        resource :my_class
          #      end
          #
          def resource(name)
            self.resource_name = name.to_s
          end

          # @api public
          #
          # Make the where criteria passing what will have inside the 'q' Solr param.
          #
          # @returns <Solr::Relation>
          #
          # @example
          #
          #   Base.where("name_pt:Saraiva").order("name_pt ASC").limit(100).page(1)
          #
          def where(criteria)
            Solr::Relation.new(connection: connection, relation_class: self, where: criteria)
          end

          # @api public
          #
          def find(id)
            where(id: id).first
          end

          # @api public
          # Make the basic search passing an object that responds to: #valid_for_basic_search?, #basic_query, #per_page and #page.
          #
          # @returns [Solr::Relation]
          #
          def basic_search(offer_search)
            # return [] unless offer_search.valid_for_basic_search?
            #
            # search(offer_search)
          end

          # @api public
          # Make the basic search passing an object that responds to: #basic_query, #per_page and #page.
          #
          # @returns [Solr::Relation]
          #
          def search(search)
            # order_query = "#{fields[offer_search.order_field_name.to_sym]} #{offer_search.order_type}"
            # where(offer_search.basic_query).per_page(offer_search.per_page).page(offer_search.page).order(order_query).filter(offer_search.filter)
          end
        end

        def ==(other)
          id == other.id
        end
      end

      class ResponseHandler
        attr_reader :resource_class

        def initialize(resource_class, options={})
          @resource_class = resource_class
          @response       = options.fetch(:response)
        end

        def docs
          response['docs'].to_a
        end

        def total
          response['numFound'].to_i
        end

        def records
          docs.collect do |document|
            resource_class.new.tap do |new_object|
              attributes = new_object.attributes
              attributes.each { |key, value| attributes[key] = document[key.to_s] }
              new_object.attributes = attributes
            end
          end
        end

        def facet_fields
          FacetFields.new(@response['facet_counts']['facet_fields'])
        end

        private

        def response
          @response['response'] || {}
        end
      end

      class FacetFields < Hash
        def initialize(fields={})
          @fields = fields
          assign_facet_field

          super
        end

        def assign_facet_field
          @fields.each do |facet_field, facet_values|
            self[facet_field] = facet_values.each_slice(2).collect do |name, count|
              FacetField.new(name: name, count: count, field: facet_field)
            end
          end
        end
      end

      class FacetField
        include ActiveModel::Model
        attr_accessor :name, :count, :field

        def ==(other_facet_field)
          name == other_facet_field.name && count == other_facet_field.count && field == other_facet_field.field
        end
      end

      module Solr
        class FacetResponseHandler
          attr_reader :field_name

          def initialize(collection_object, options={})
            @collection_object = collection_object
            @response          = options.fetch(:response)
            @field_name        = options[:field_name] || 'name_so'
          end

          def records
            facet_fields[@field_name].each_slice(2).collect do |new_field_name, count|
              @collection_object.new(@field_name => new_field_name)
            end
          end

          def facet_fields
            @response['facet_counts']['facet_fields']
          end
        end
      end
  end
end