Question

My app has Machines that have and belong to many Specifications

class Machine < ActiveRecord::Base
  has_and_belongs_to_many :specs

Specifications have both field (width, weight, capacity, horsepower) and value attributes.

The search is done entirely through Solr through Sunspot.

I’d like to be able to find a Machine based on its Specifications, such as find all machines with Width greater than 50.

I know I can index spec_field and spec_valueseparately, but it will filter for specs with value more than 50, which could include fields I don’t want, such as height or capacity (so searching for width > 50 will yield capacity > 50 in results).

Ideally, I’d like to assign each Specification of a Machine to its own indexed field along with its value, so that my index has field such as “height” or “weight”, but the specifications are flexible, and some machines have one set of specs while another machine has a different set, so it doesn’t look like it can work out.

Can it even be done with Solr?

Answer 1

Solution Found

The Solution I found was to use “Dynamic Fields” as described here

INDEXING

dynamic_integer :specs do
  specs.inject({}) do |hash,spec|
    hash.merge(spec.spec_field.label.to_sym => spec.value)
  end
end

QUERY

  dynamic :specs do
    if params[:specs].present?
      for spec in params[:specs]
        case spec[:condition]
          when "gt"
            with(spec[:field]).greater_than(spec[:value])
          when "lt"
            with(spec[:field]).less_than(spec[:value])
          else
            with(spec[:field],spec[:value])
        end
      end
    end
  end

SOLR keeps looking better and better to me!