Rails Sunspot + spatial search + group by parent

Question

My app have a list of Routes, and each route has a list of Steps. I'm using Solr/Sunpost to index the step lat/lng coordinate do do some searches. Piece of code:

class Step < ActiveRecord::Base
   belongs_to :route
   searchable do
        integer :route_id, :references => Route
        latlon(:coordinates) { Sunspot::Util::Coordinates.new(lat, lng) }
   end
end

I can make searches using the order_by_geodist() from Sunspot, it works ok:

s = Step.search do
   order_by_geodist(:coordinates, lat, lng)
end

The thing is: is there a way to group the results by route_id? In other words, I want to return only one step for each route.

Answer 1

Resolved with the "group" option

s = Step.search do
      group :route_id
      order_by_geodist(:coordinates, lat, lng)
end

s.group(:route_id).groups.each do |g|
  logger.info g.value
  logger.info g.results[0].inspect
end