[#7] [Backend] As a User, I can query a single keyword and get its Google search results parsed

Gemfile

@@ -15,6 +15,7 @@ gem 'bootsnap', require: false # Reduces boot times through caching; required in
 gem 'i18n-js', '3.5.1' # A library to provide the I18n translations on the Javascript
 gem 'jsonapi-serializer' # A fast JSON:API serializer for Ruby Objects.
 gem 'httparty' # A HTTP client for Ruby.
+gem 'nokogiri' # Nokogiri makes it easy and painless to work with XML and HTML from Ruby
 
 # Authentications & Authorizations
 gem 'devise' # Authentication solution for Rails with Warden

Gemfile.lock

@@ -506,6 +506,7 @@ DEPENDENCIES
   letter_opener
   listen (= 3.1.5)
   mini_magick
+  nokogiri
   pagy
   pg
   pry-byebug

app/services/google/parser_service.rb

@@ -0,0 +1,69 @@
+# frozen_string_literal: true
+
+module Google
+  class ParserService
+    NON_ADS_RESULT_SELECTOR = 'a[data-ved]:not([role]):not([jsaction]):not(.adwords):not(.footer-links)'
+    AD_CONTAINER_ID = 'tads'
+    ADWORDS_CLASS = 'adwords'
+
+    def initialize(html_response:)
+      raise ArgumentError, 'response.body cannot be blank' if html_response.body.blank?
+
+      @html = html_response
+
+      @document = Nokogiri::HTML.parse(html_response)
+
+      # Add a class to all AdWords link for easier manipulation
+      document.css('div[data-text-ad] a[data-ved]').add_class(ADWORDS_CLASS)
+
+      # Mark footer links to identify them
+      document.css('#footcnt a').add_class('footer-links')
+    end
+
+    # Parse html data and return a hash with the results
+    def call
+      {
+        ads_top_count: ads_top_count,
+        ads_page_count: ads_page_count,
+        ads_top_url: ads_top_url,
+        ads_page_url: ads_page_url,
+        non_ads_result_count: non_ads_result_count,
+        non_ads_url: non_ads_url,
+        total_link_count: total_link_count,
+        html: html
+      }
+    end
+
+    private
+
+    attr_reader :html, :document
+
+    def ads_top_count
+      document.css("##{AD_CONTAINER_ID} .#{ADWORDS_CLASS}").count
+    end
+
+    def ads_page_count
+      document.css(".#{ADWORDS_CLASS}").count
+    end
+
+    def ads_top_url
+      document.css("##{AD_CONTAINER_ID} .#{ADWORDS_CLASS}").map { |a_tag| a_tag['href'] }
+    end
+
+    def ads_page_url
+      document.css(".#{ADWORDS_CLASS}").map { |a_tag| a_tag['href'] }
+    end
+
+    def non_ads_result_count
+      document.css(NON_ADS_RESULT_SELECTOR).count
+    end
+
+    def non_ads_url
+      document.css(NON_ADS_RESULT_SELECTOR).map { |a_tag| a_tag['href'] }
+    end
+
+    def total_link_count
+      document.css('a').count
+    end
+  end
+end

spec/services/google/client_service_spec.rb

@@ -3,34 +3,36 @@
 require 'rails_helper'
 
 RSpec.describe Google::ClientService, type: :service do
-  context 'when querying a simple keyword' do
-    it 'returns an HTTParty Response', vcr: 'google_search' do
-      result = described_class.new(keyword: FFaker::Lorem.word).call
+  describe '#call' do
+    context 'when querying a simple keyword' do
+      it 'returns an HTTParty Response', vcr: 'google_search/base' do
+        result = described_class.new(keyword: FFaker::Lorem.word).call
 
-      expect(result).to be_an_instance_of(HTTParty::Response)
-    end
+        expect(result).to be_an_instance_of(HTTParty::Response)
+      end
 
-    it 'queries Google Search', vcr: 'google_search' do
-      path = described_class.new(keyword: FFaker::Lorem.word).call.request.path
+      it 'queries Google Search', vcr: 'google_search/base' do
+        path = described_class.new(keyword: FFaker::Lorem.word).call.request.path
 
-      expect(path.to_s).to start_with(described_class::BASE_SEARCH_URL)
+        expect(path.to_s).to start_with(described_class::BASE_SEARCH_URL)
+      end
     end
-  end
 
-  context 'when google returns an HTTP error' do
-    it 'returns false', vcr: 'google_warn' do
-      result = described_class.new(keyword: FFaker::Lorem.word).call
+    context 'when google returns an HTTP error' do
+      it 'returns false', vcr: 'google_search/too_many_requests' do
+        result = described_class.new(keyword: FFaker::Lorem.word).call
 
-      expect(result).to eq(false)
-    end
+        expect(result).to eq(false)
+      end
 
-    it 'logs a warning with the escaped keyword', vcr: 'google_warn' do
-      allow(Rails.logger).to receive(:warn)
+      it 'logs a warning with the escaped keyword', vcr: 'google_search/too_many_requests' do
+        allow(Rails.logger).to receive(:warn)
 
-      word = FFaker::Lorem.word
-      described_class.new(keyword: word).call
+        word = FFaker::Lorem.word
+        described_class.new(keyword: word).call
 
-      expect(Rails.logger).to have_received(:warn).with(/#{CGI.escape(word)}/)
+        expect(Rails.logger).to have_received(:warn).with(/#{CGI.escape(word)}/)
+      end
     end
   end
 end

spec/services/google/parser_service_spec.rb

@@ -0,0 +1,54 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe Google::ParserService, type: :service do
+  describe '#call' do
+    context 'when parsing a page having 1 top ad' do
+      it 'counts exactly 1 top ad', vcr: 'google_search/top_ads_1' do
+        result = Google::ClientService.new(keyword: 'squarespace').call
+
+        expect(described_class.new(html_response: result).call[:ads_top_count]).to eq(1)
+      end
+    end
+
+    context 'when parsing a page having 3 top ads, 3 bottom ads and 14 non ad links' do
+      it 'counts exactly 3 top ads', vcr: 'google_search/top_ads_6' do
+        result = Google::ClientService.new(keyword: 'vpn').call
+
+        expect(described_class.new(html_response: result).call[:ads_top_count]).to eq(3)
+      end
+
+      it 'counts exactly 6 ads in total', vcr: 'google_search/top_ads_6' do
+        result = Google::ClientService.new(keyword: 'vpn').call
+
+        expect(described_class.new(html_response: result).call[:ads_page_count]).to eq(6)
+      end
+
+      it 'finds exactly the 3 top ads urls', vcr: 'google_search/top_ads_6' do
+        result = Google::ClientService.new(keyword: 'vpn').call
+
+        expect(described_class.new(html_response: result).call[:ads_top_url]).to contain_exactly('https://cloud.google.com/free', 'https://www.expressvpn.com/', 'https://www.top10vpn.com/best-vpn-for-vietnam/')
+      end
+
+      it 'counts exactly 14 non ad results', vcr: 'google_search/top_ads_6' do
+        result = Google::ClientService.new(keyword: 'vpn').call
+
+        expect(described_class.new(html_response: result).call[:non_ads_result_count]).to eq(14)
+      end
+
+      it 'gets 14 results', vcr: 'google_search/top_ads_6' do
+        result = Google::ClientService.new(keyword: 'vpn').call
+
+        expect(described_class.new(html_response: result).call[:non_ads_url].count).to eq(14)
+      end
+
+      it 'gets exactly 113 links', vcr: 'google_search/top_ads_6' do
+        # Counted from cassette html raw code
+        result = Google::ClientService.new(keyword: 'vpn').call
+
+        expect(described_class.new(html_response: result).call[:total_link_count]).to eq(113)
+      end
+    end
+  end
+end

spec/support/vcr.rb

@@ -10,6 +10,10 @@
   c.ignore_request do |request|
     URI(request.uri).port == 9200
   end
+  # Uncomment when need to record a cassette with readable Html
+  # c.before_record do |i|
+  #   i.response.body.force_encoding('UTF-8')
+  # end
   c.default_cassette_options = { record: :none, match_requests_on: [:path] }
 end