Add page and article limit options (#6349) [deploy]

app/services/articles/feed.rb

@@ -16,12 +16,13 @@ module Articles
     # Timeframe values from Timeframer::DATETIMES
     def top_articles_by_timeframe(timeframe:)
       published_articles_by_tag.where("published_at > ?", Timeframer.new(timeframe).datetime).
-        order("score DESC")
+        order("score DESC").page(@page).per(@number_of_articles)
     end
 
     def latest_feed
       published_articles_by_tag.order("published_at DESC").
-        where("featured_number > ? AND score > ?", 1_449_999_999, -40)
+        where("featured_number > ? AND score > ?", 1_449_999_999, -40).
+        page(@page).per(@number_of_articles)
     end
 
     def default_home_feed_and_featured_story(user_signed_in: false)
@@ -51,7 +52,8 @@ module Articles
         article_points = score_single_article(article)
         result[article] = article_points
       end
-      ranked_articles.sort_by { |_article, article_points| -article_points }.map(&:first)
+      ranked_articles = ranked_articles.sort_by { |_article, article_points| -article_points }.map(&:first)
+      ranked_articles.to(@number_of_articles - 1)
     end
 
     def score_single_article(article)
@@ -70,6 +72,8 @@ module Articles
     end
 
     def score_followed_tags(article)
+      return 0 unless @user
+
       article_tags = article.decorate.cached_tag_list_array
       @user.decorate.cached_followed_tags.sum do |tag|
         article_tags.include?(tag.name) ? tag.points : 0
@@ -92,11 +96,11 @@ module Articles
     end
 
     def score_language(article)
-      @user.preferred_languages_array.include?(article.language || "en") ? 1 : -10
+      @user&.preferred_languages_array&.include?(article.language || "en") ? 1 : -10
     end
 
     def score_experience_level(article)
-      - ((article.experience_level_rating - (@user.experience_level || 5).abs) / 2)
+      - ((article.experience_level_rating - (@user&.experience_level || 5).abs) / 2)
     end
   end
 end

spec/services/articles/feed_spec.rb

@@ -287,4 +287,27 @@ RSpec.describe Articles::Feed, type: :service do
       end
     end
   end
+
+  describe "#rank_and_sort_articles" do
+    let(:article1) { create(:article) }
+    let(:article2) { create(:article) }
+    let(:article3) { create(:article) }
+    let(:articles) { [article1, article2, article3] }
+
+    context "when number of articles specified" do
+      let(:feed) { described_class.new(number_of_articles: 1) }
+
+      it "only returns the requested number of articles" do
+        expect(feed.rank_and_sort_articles(articles).size).to eq 1
+      end
+    end
+
+    it "returns articles in scored order" do
+      allow(feed).to receive(:score_single_article).with(article1).and_return(1)
+      allow(feed).to receive(:score_single_article).with(article2).and_return(2)
+      allow(feed).to receive(:score_single_article).with(article3).and_return(3)
+
+      expect(feed.rank_and_sort_articles(articles)).to eq [article3, article2, article1]
+    end
+  end
 end