sunspot_config.rb

# Hook our MongoMapper model into Solr
module MongoAdapter
  class InstanceAdapter < Sunspot::Adapters::InstanceAdapter
    def id
      @instance.id
    end
  end

  class DataAccessor < Sunspot::Adapters::DataAccessor
    def load(id)
      @clazz.find(id)
    end
  end
end

Sunspot::Adapters::DataAccessor.register(MongoAdapter::DataAccessor, User)
Sunspot::Adapters::InstanceAdapter.register(MongoAdapter::InstanceAdapter, User)

Sunspot.setup(User) do
  text :name
  text :screen_name
  text :description
  
  string :screen_name
  
  string :flists, :multiple => true do
    listed_on.map{|l| l.keys.first.downcase.split(/-|_|\//)}.flatten
  end
  
  dynamic_text :lists do
    count = 0
    listed_on.inject({}) do |hash, l|
      hash["#{count}_#{l.keys.first}".to_sym] = {
        :value => l.keys.first,
        :boost => l.values.first == 0 ? 1 : l.values.first
      }
      count += 1
      hash
    end
  end
end