[15 Min Fix]: Extract a post's followers out of service and onto Article model (#13229)

* Move authors followers out of Notifications::NotifiableAction::Send and into Article model

* Rename authors_followers to followers

* Update followers method in service, oops

* Update app/services/notifications/notifiable_action/send.rb

Co-authored-by: Michael Kohl <citizen428@dev.to>

Co-authored-by: Michael Kohl <citizen428@dev.to>

app/models/article.rb

@@ -435,6 +435,19 @@ class Article < ApplicationRecord
     doc.to_html
   end
 
+  def followers
+    # This will return an array, but the items will NOT be ActiveRecord objects.
+    # The followers may also occasionally be nil because orphaned follows can possibly exist in the database.
+    followers = user.followers_scoped.where(subscription_status: "all_articles").map(&:follower)
+
+    if organization_id
+      org_followers = organization.followers_scoped.where(subscription_status: "all_articles")
+      followers += org_followers.map(&:follower)
+    end
+
+    followers.uniq.compact
+  end
+
   private
 
   def search_score

app/services/notifications/notifiable_action/send.rb

@@ -16,6 +16,8 @@ module Notifications
       end
 
       def call
+        return unless notifiable.is_a?(Article)
+
         json_data = {
           user: user_data(notifiable.user),
           article: article_data(notifiable)
@@ -23,9 +25,7 @@ module Notifications
         json_data[:organization] = organization_data(notifiable.organization) if notifiable.organization_id
 
         notifications_attributes = []
-        # followers is an array and not an activerecord object
-        # followers can occasionally be nil because orphaned follows can possibly exist in the db (for now)
-        followers.sort_by(&:updated_at).reverse[0..10_000].each do |follower|
+        notifiable.followers.sort_by(&:updated_at).last(10_000).reverse_each do |follower|
           now = Time.current
           notifications_attributes.push(
             user_id: follower.id,
@@ -53,17 +53,6 @@ module Notifications
 
       attr_reader :notifiable, :action
 
-      def followers
-        followers = notifiable.user.followers_scoped.where(subscription_status: "all_articles").map(&:follower)
-
-        if notifiable.organization_id
-          org_followers = notifiable.organization.followers_scoped.where(subscription_status: "all_articles")
-          followers += org_followers.map(&:follower)
-        end
-
-        followers.uniq.compact
-      end
-
       def choose_upsert_index(action)
         return :index_notifications_on_user_notifiable_and_action_not_null if action.present?
 

app/workers/notifications/notifiable_action_worker.rb

@@ -4,7 +4,7 @@ module Notifications
 
     sidekiq_options queue: :low_priority, retry: 10
     def perform(notifiable_id, notifiable_type, action)
-      # checking type, but leaving space for notifyable types
+      # checking type, but leaving space for notifiable types
       return unless notifiable_type == "Article"
 
       notifiable = notifiable_type.constantize.find_by(id: notifiable_id)

spec/models/article_spec.rb

@@ -1118,6 +1118,16 @@ RSpec.describe Article, type: :model do
     end
   end
 
+  describe "#followers" do
+    it "returns an array of users who follow the article's author" do
+      following_user = create(:user)
+      following_user.follow(user)
+
+      expect(article.followers.length).to eq(1)
+      expect(article.followers.first.username).to eq(following_user.username)
+    end
+  end
+
   describe "#update_score" do
     it "stably sets the correct blackbox values" do
       create(:reaction, reactable: article, points: 1)