Add support for ingesting etag data from API endpoints

lib/yt/actions/list.rb

@@ -12,15 +12,22 @@ def first!
         first.tap{|item| raise Errors::NoItems, error_message unless item}
       end
 
+      def etag
+        @etag ||= fetch_etag
+      end
+
     private
 
       def list
+        owner = self
         @last_index, @page_token = 0, nil
         Enumerator.new(-> {total_results}) do |items|
           while next_item = find_next
             items << next_item
           end
           @where_params = {}
+        end.tap do |enum|
+          enum.define_singleton_method(:etag) { owner.instance_variable_get(:@etag) }
         end
       end
 
@@ -63,7 +70,7 @@ def resource_class
       #   Can be overwritten by subclasses that initialize instance with
       #   a different set of parameters.
       def new_item(data)
-        resource_class.new attributes_for_new_item(data)
+        resource_class.new attributes_for_new_item(data).merge(etag: data['etag'])
       end
 
       # @private
@@ -91,11 +98,17 @@ def eager_load_items_from(items)
 
       def fetch_page(params = {})
         @last_response = list_request(params).run
+        @etag = @last_response.body['etag']
         token = @last_response.body['nextPageToken']
         items = extract_items @last_response.body
         {items: items, token: token}
       end
 
+      def fetch_etag
+        response = list_request(list_params).run
+        response.body['etag']
+      end
+
       def list_request(params = {})
         @list_request = Yt::Request.new(params).tap do |request|
           print "#{request.as_curl}\n" if Yt.configuration.developing?

lib/yt/collections/assets.rb

@@ -17,7 +17,7 @@ def insert(attributes = {})
 
       def new_item(data)
         klass = (data["kind"] == "youtubePartner#assetSnippet") ? Yt::AssetSnippet : Yt::Asset
-        klass.new attributes_for_new_item(data)
+        klass.new attributes_for_new_item(data).merge(etag: data['etag'])
       end
 
       # @return [Hash] the parameters to submit to YouTube to list assets

lib/yt/collections/playlist_items.rb

@@ -42,7 +42,9 @@ def list_params
       end
 
       def playlist_items_params
-        resources_params.merge playlist_id: @parent.id
+        params = resources_params
+        params.merge!(playlist_id: @parent.id) if @parent
+        apply_where_params! params
       end
 
       def insert_parts

lib/yt/collections/resources.rb

@@ -19,7 +19,7 @@ def insert(attributes = {}, options = {}) #
     private
 
       def attributes_for_new_item(data)
-        {id: data['id'], snippet: data['snippet'], status: data['status'], auth: @auth}
+        {id: data['id'], snippet: data['snippet'], status: data['status'], auth: @auth, etag: data['etag']}
       end
 
       def resources_params

lib/yt/models/playlist.rb

@@ -209,11 +209,6 @@ def reports_params
         end
       end
 
-      # @private
-      def exists?
-        !@id.nil?
-      end
-
     private
 
       # @see https://developers.google.com/youtube/v3/docs/playlists/update

lib/yt/models/playlist_item.rb

@@ -83,11 +83,6 @@ def video
 
     ### PRIVATE API ###
 
-      # @private
-      def exists?
-        !@id.nil?
-      end
-
       # @private
       # Override Resource's new to set video if the response includes it
       def initialize(options = {})

lib/yt/models/resource.rb

@@ -20,6 +20,19 @@ def id
         end
       end
 
+    ### ETAG ###
+      def etag
+        return nil unless exists?
+
+        @etag ||= fetch_etag
+      end
+
+    ### EXISTS? ###
+
+      def exists?
+        !@id.nil?
+      end
+
     ### STATUS ###
 
       has_one :status
@@ -56,6 +69,7 @@ def initialize(options = {})
           @id = options[:id]
         end
         @auth = options[:auth]
+        @etag = options[:etag]
         @snippet = Snippet.new(data: options[:snippet]) if options[:snippet]
         @status = Status.new(data: options[:status]) if options[:status]
       end
@@ -139,6 +153,19 @@ def fetch_channel_id
         end
       end
 
+      def fetch_etag
+        return nil if @id.nil?
+
+        collection = resource_collection.new(auth: @auth).where(id: @id)&.first
+        collection&.etag
+      end
+
+      def resource_collection
+        name = self.class.to_s.demodulize.pluralize
+        require "yt/collections/#{name.underscore}"
+        "Yt::Collections::#{name}".constantize
+      end
+
       # Since YouTube API only returns tags on Videos#list, the memoized
       # `@snippet` is erased if the video was instantiated through Video#search
       # (e.g., by calling account.videos or channel.videos), so that the full

lib/yt/models/video.rb

@@ -635,11 +635,6 @@ def initialize(options = {})
         end
       end
 
-      # @private
-      def exists?
-        !@id.nil?
-      end
-
       # @private
       # Tells `has_reports` to retrieve the reports from YouTube Analytics API
       # either as a Channel or as a Content Owner.

spec/collections/channels_spec.rb

@@ -0,0 +1,20 @@
+require 'spec_helper'
+require 'yt/collections/channels'
+
+describe Yt::Collections::Channels do
+  subject(:collection) { Yt::Collections::Channels.new }
+
+  describe '#etag' do
+    let(:etag) { 'etag123' }
+
+    before do
+      expect_any_instance_of(Yt::Request).to receive(:run).once do
+        double(body: {'etag'=> etag, 'items'=> [], 'pageInfo'=> {'totalResults'=>0}})
+      end
+    end
+
+    it 'returns the etag from the list response' do
+      expect(collection.etag).to eq etag
+    end
+  end
+end

spec/collections/comment_threads_spec.rb

@@ -43,4 +43,19 @@
       end
     end
   end
+
+  describe '#etag' do
+    let(:parent) { Yt::Video.new id: 'any-id' }
+    let(:etag) { 'etag123' }
+
+    before do
+      expect_any_instance_of(Yt::Request).to receive(:run).once do
+        double(body: {'etag'=> etag, 'items'=> [], 'pageInfo'=> {'totalResults'=>0}})
+      end
+    end
+
+    it 'returns the etag from the list response' do
+      expect(collection.etag).to eq etag
+    end
+  end
 end

spec/collections/playlist_items_spec.rb

@@ -41,4 +41,19 @@
 
     it { expect(collection.delete_all).to eq [true] }
   end
-end
+
+  describe '#etag' do
+    let(:etag) { 'etag123' }
+    let(:behave) { receive(:fetch_etag).and_call_original }
+
+    before do
+      expect_any_instance_of(Yt::Request).to receive(:run).once do
+        double(body: {'etag'=> etag, 'items'=> [], 'pageInfo'=> {'totalResults'=>0}})
+      end
+    end
+
+    it 'returns the etag from the list response' do
+      expect(collection.etag).to eq etag
+    end
+  end
+end

spec/collections/playlists_spec.rb

@@ -24,4 +24,19 @@
 
     it { expect(collection.delete_all).to eq [true] }
   end
-end
+
+  describe '#etag' do
+    let(:etag) { 'etag123' }
+    let(:behave) { receive(:fetch_etag).and_call_original }
+
+    before do
+      expect_any_instance_of(Yt::Request).to receive(:run).once do
+        double(body: {'etag'=> etag, 'items'=> [], 'pageInfo'=> {'totalResults'=>0}})
+      end
+    end
+
+    it 'returns the etag from the list response' do
+      expect(collection.etag).to eq etag
+    end
+  end
+end

spec/collections/subscriptions_spec.rb

@@ -2,7 +2,7 @@
 require 'yt/collections/subscriptions'
 
 describe Yt::Collections::Subscriptions do
-  subject(:collection) { Yt::Collections::Subscriptions.new }
+  subject(:collection) { Yt::Collections::Subscriptions.new parent: Yt::Channel.new(id: 'any-id') }
   let(:msg) { {response_body: {error: {errors: [{reason: reason}]}}}.to_json }
   before { expect(collection).to behave }
 
@@ -22,4 +22,19 @@
       it { expect{collection.insert ignore_errors: true}.not_to fail }
     end
   end
-end
+
+  describe '#etag' do
+    let(:etag) { 'etag123' }
+    let(:behave) { receive(:fetch_etag).and_call_original }
+
+    before do
+      expect_any_instance_of(Yt::Request).to receive(:run).once do
+        double(body: {'etag'=> etag, 'items'=> [], 'pageInfo'=> {'totalResults'=>0}})
+      end
+    end
+
+    it 'returns the etag from the list response' do
+      expect(collection.etag).to eq etag
+    end
+  end
+end

spec/collections/videos_spec.rb

@@ -40,4 +40,19 @@
       end
     end
   end
+
+  describe '#etag' do
+    let(:etag) { 'etag123' }
+
+    before do
+      expect_any_instance_of(Yt::Request).to receive(:run).once do
+        double(body: {'etag'=> etag, 'items'=> [], 'pageInfo'=> {'totalResults'=>0}})
+      end
+    end
+
+    it 'returns the etag from the list response' do
+      collection.count
+      expect(collection.etag).to eq etag
+    end
+  end
 end

spec/models/channel_spec.rb

@@ -4,6 +4,13 @@
 describe Yt::Channel do
   subject(:channel) { Yt::Channel.new attrs }
 
+  describe '#etag' do
+    context 'given the API response includes an etag' do
+      let(:attrs) { {id: 'any-id', etag: '12345'} }
+      it { expect(channel.etag).to eq '12345' }
+    end
+  end
+
   describe '#title' do
     context 'given a snippet with a title' do
       let(:attrs) { {snippet: {"title"=>"Fullscreen"}} }

spec/models/playlist_spec.rb

@@ -4,6 +4,47 @@
 describe Yt::Playlist do
   subject(:playlist) { Yt::Playlist.new attrs }
 
+  describe '#etag' do
+    context 'given the API response includes an etag' do
+      let(:attrs) { {id: 'any-id', etag: 'etag123'} }
+      it { expect(playlist.etag).to eq 'etag123' }
+    end
+
+    context 'given only an ID is provided' do
+      let(:attrs) { {id: 'any-id', auth: double('auth')} }
+      let(:etag) { 'etag123' }
+
+      before do
+        expect_any_instance_of(Yt::Request).to receive(:run).once do
+          double(body: {'etag' => etag, 'items'=> [{'id'=> 'any-id', 'etag'=> etag}], 'pageInfo'=> {'totalResults'=> 1}})
+        end
+      end
+
+      it 'fetches the etag from YouTube' do
+        expect(playlist.etag).to eq etag
+      end
+    end
+
+    context 'given an ID is provided but no auth' do
+      let(:attrs) { {id: 'any-id'} }
+
+      it 'returns the etag from the API response even if no items are found' do
+        expect_any_instance_of(Yt::Request).to receive(:run).once do
+          double(body: {'etag' => 'mockedEtag', 'items'=> [], 'pageInfo'=> {'totalResults'=> 0}})
+        end
+        expect(playlist.etag).to eq 'mockedEtag'
+      end
+    end
+
+    context 'given no ID is provided' do
+      let(:attrs) { {} }
+
+      it 'returns nil' do
+        expect_any_instance_of(Yt::Request).not_to receive(:run)
+        expect(playlist.etag).to be_nil
+      end
+    end
+  end
 
   describe '#title' do
     context 'given a snippet with a title' do