gistfile1.rb

# define search method to be used in Rails controller
    def search(query=nil, options={})

      options ||= {}

      # setup empty search definition
      @search_definition = {
        query: {},
        filter: {},
        facets: {},
      }

      # Prefill and set the filters (top-level `filter` and `facet_filter` elements)
      __set_filters = lambda do |key, f|

        @search_definition[:filter][:and] ||= []
        @search_definition[:filter][:and]  |= [f]

        @search_definition[:facets][key.to_sym][:facet_filter][:and] ||= []
        @search_definition[:facets][key.to_sym][:facet_filter][:and]  |= [f]
      end

      # facets
      @search_definition[:facets] = search_facet_fields.each_with_object({}) do |a,hsh|
        hsh[a.to_sym] = {
          terms: {
            field: a
          },
          facet_filter: {}
        }
      end

      # query
      unless query.blank?
        @search_definition[:query] = {
          bool: {
            should: [
              { multi_match: {
                  query: query,
                  # limit which fields to search, or boost here:
                  fields: search_text_fields,
                  operator: 'and'
                }
              }
            ]
          }
        }
      else
        @search_definition[:query] = { match_all: {} }
      end

      # add filters for facets
      options.each do |key,value|
        next unless search_facet_fields.include?(key)

        f = { term: { key.to_sym => value } }

        __set_filters.(key, f)

      end

      # execute Elasticsearch search
      __elasticsearch__.search(@search_definition)

    end