Make less queries when displaying articles flare tags (#1957)

* Make less queries when displaying flare tag

* Make less sql queries to display articles flare tags

app/labor/flare_tag.rb

@@ -1,27 +1,25 @@
 class FlareTag
-  attr_accessor :article
-  def initialize(article)
+  FLARES = %w[explainlikeimfive
+              ama
+              techtalks
+              help
+              news
+              healthydebate
+              showdev
+              challenge
+              anonymous
+              hiring
+              discuss].freeze
+
+  def initialize(article, except_tag = nil)
     @article = article.decorate
+    @except_tag = except_tag
   end
 
   def tag
-    Rails.cache.
-      fetch("article_flare_tag-#{article.id}-#{article.updated_at}", expires_in: 12.hours) do
-      flares = ["explainlikeimfive",
-                "ama",
-                "techtalks",
-                "help",
-                "news",
-                "healthydebate",
-                "showdev",
-                "challenge",
-                "anonymous",
-                "hiring",
-                "discuss"]
-      flares.each do |f|
-        return Tag.find_by_name(f) if article.cached_tag_list_array.include?(f)
-      end
-      nil
+    @tag ||= Rails.cache.fetch("article_flare_tag-#{article.id}-#{article.updated_at}", expires_in: 12.hours) do
+      flare = FLARES.detect { |f| article.cached_tag_list_array.include?(f) }
+      flare && flare != except_tag ? Tag.find_by_name(flare) : nil
     end
   end
 
@@ -32,4 +30,8 @@ class FlareTag
       bg_color_hex: tag.bg_color_hex,
       text_color_hex: tag.text_color_hex }
   end
+
+  private
+
+  attr_reader :article, :except_tag
 end

app/models/article.rb

@@ -333,7 +333,7 @@ class Article < ApplicationRecord
   end
 
   def flare_tag
-    FlareTag.new(self).tag_hash
+    @flare_tag ||= FlareTag.new(self).tag_hash
   end
 
   def update_main_image_background_hex

app/views/articles/_tag_identifier.html.erb

@@ -1,5 +1,7 @@
-<% if FlareTag.new(story).tag && @tag != FlareTag.new(story).tag.name %>
-  <span class="tag-identifier black-identifier" style="background:<%= FlareTag.new(story).tag.bg_color_hex %>;color:<%= FlareTag.new(story).tag.text_color_hex %>">#<%= FlareTag.new(story).tag.name %></span><%= story.title %>
-<% else %>
-  <%= story.title %>
+<% flare_tag = FlareTag.new(story, @tag).tag %>
+<% if flare_tag %>
+  <span class="tag-identifier black-identifier" style="background:<%= flare_tag.bg_color_hex %>;color:<%= flare_tag.text_color_hex %>">
+    #<%= flare_tag.name %>
+  </span>
 <% end %>
+<%= story.title %>

spec/labor/flare_tag_spec.rb

@@ -0,0 +1,48 @@
+require "rails_helper"
+
+RSpec.describe FlareTag do
+  let(:user) { create(:user) }
+  let(:article) { create(:article, user_id: user.id) }
+
+  describe "#flare_tag" do
+    it "returns nil if there is no flare tag" do
+      expect(described_class.new(article).tag).to be nil
+    end
+
+    it "returns a flare tag if there is a flare tag in the list" do
+      valid_article = create(:article, tags: "ama")
+      expect(described_class.new(valid_article).tag.name).to eq("ama")
+    end
+
+    it "returns nil if an except is provided" do
+      valid_article = create(:article, tags: "explainlikeimfive")
+      expect(described_class.new(valid_article, "explainlikeimfive").tag).to eq(nil)
+    end
+
+    it "returns a flare tag if there are 2 flare tags in the list" do
+      valid_article = create(:article, tags: ["ama", "explainlikeimfive"])
+      expect(described_class.new(valid_article).tag.name).to eq("explainlikeimfive")
+    end
+  end
+
+  describe "#flare_tag_hash" do
+    let (:tag) { create(:tag, name: "ama", bg_color_hex: "#f3f3f3", text_color_hex: "#cccccc") }
+    let (:valid_article) { create(:article, tags: tag.name) }
+
+    it "returns nil if an article doesn't have a flare tag" do
+      expect(described_class.new(article).tag_hash).to be nil
+    end
+
+    it "returns a hash with the flare tag's name" do
+      expect(described_class.new(valid_article).tag_hash.value?("ama")).to be true
+    end
+
+    it "returns a hash with the flare tag's bg_color_hex" do
+      expect(described_class.new(valid_article).tag_hash.value?("#f3f3f3")).to be true
+    end
+
+    it "returns a hash with the flare tag's text_color_hex" do
+      expect(described_class.new(valid_article).tag_hash.value?("#cccccc")).to be true
+    end
+  end
+end

spec/models/article_spec.rb

@@ -370,38 +370,6 @@ RSpec.describe Article, type: :model do
     end
   end
 
-  describe "#flare_tag" do
-    it "returns nil if there is no flare tag" do
-      expect(FlareTag.new(article).tag).to be nil
-    end
-
-    it "returns a flare tag if there is a flare tag in the list" do
-      valid_article = create(:article, tags: "ama")
-      expect(FlareTag.new(valid_article).tag.name).to eq("ama")
-    end
-  end
-
-  describe "#flare_tag_hash" do
-    let (:tag) { create(:tag, name: "ama", bg_color_hex: "#f3f3f3", text_color_hex: "#cccccc") }
-    let (:valid_article) { create(:article, tags: tag.name) }
-
-    it "returns nil if an article doesn't have a flare tag" do
-      expect(FlareTag.new(article).tag_hash).to be nil
-    end
-
-    it "returns a hash with the flare tag's name" do
-      expect(FlareTag.new(valid_article).tag_hash.value?("ama")).to be true
-    end
-
-    it "returns a hash with the flare tag's bg_color_hex" do
-      expect(FlareTag.new(valid_article).tag_hash.value?("#f3f3f3")).to be true
-    end
-
-    it "returns a hash with the flare tag's text_color_hex" do
-      expect(FlareTag.new(valid_article).tag_hash.value?("#cccccc")).to be true
-    end
-  end
-
   describe "before save" do
     # before do
     #   article = create(:article, user_id: user.id)