A simplified version of our Elasticsearch query library at Wootric, including a few examples

elasticsearch.rb

require 'rest-client'
require 'json'

class Elasticsearch
  class << self
    attr_accessor :url

    def configured?
      url.present?
    end 

    def create_index(name, options = {}) 
      response = RestClient.put "#{url}/#{name}", options.to_json
      fail if JSON.parse(response.body)['acknowledged'] != true
    end 

    def delete_index(name)
      response = RestClient.delete "#{url}/#{name}"
      fail if JSON.parse(response.body)['acknowledged'] != true
    end 

    def index_exists?(name)
      RestClient.head "#{url}/#{name}"
      return true
    rescue RestClient::ResourceNotFound
      return false
    end 

    def index_document(index_name:, type:, document:, options: {}) 
      response = RestClient::Request.execute(
        method: 'PUT',
        url: "#{url}/#{index_name}/#{type}/#{document[:id]}",
        headers: { params: options },
        payload: document.to_json
      )   
      fail unless JSON.parse(response.body)['_shards']['successful'] >= 1
    end 

    def delete_document(index_name:, type:, id:, options: {}) 
      response = RestClient::Request.execute(
        method: 'DELETE',
        url: "#{url}/#{index_name}/#{type}/#{id}",
        headers: { params: options }
      )   
      fail unless JSON.parse(response.body)['_shards']['successful'] >= 1
    end

    def search(index_name:, type: nil, query:, options: {}) 
      payload = { query: query }.merge(options).to_json
      Rails.logger.debug "Elasticsearch query: #{payload}"
      response = RestClient::Request.execute(
        method: 'GET',
        url: "#{url}/#{index_name}/#{type ? type + '/' : ''}_search",
        payload: payload
      )
      JSON.parse(response.body)
    end
  end
end

sample_queries.rb

require 'elasticsearch'
Elasticsearch.url = 'http://localhost:9200'

# index a document:
Elasticsearch.index_document(
  type: 'responses',
  document: { id: 1, score: 10, text: '<3' }.to_json
)

# find documents:
ids = Elasticsearch.search(
  type: 'responses',
  query: { match: { score: 10 } },
)['hits']['hits'].map { |r| r['_id'].to_i }