FEATURE: Add following feed to /filter (#148)

* FEATURE: Add following feed to `/filter`

Adds `following-feed:<username>` to the `/filter` endpoint

It returns the topics from the users that the current user is following(topics from the `/my/follow/feed` page).

* DEV: lint

* DEV: create `topics_for` method

create tests for it and update `/filter` to use it

* DEV: use `Topic` scope methods

Author: Grubba27

app/models/user_follower.rb

@@ -26,6 +26,26 @@ def self.posts_for(user, current_user:, limit: nil, created_before: nil, created
     results
   end
 
+  def self.topics_for(user, current_user:, limit: nil, created_before: nil, created_after: nil)
+    results =
+      Topic
+        .joins(:user)
+        .joins("INNER JOIN user_followers ON user_followers.user_id = users.id")
+        .preload(:user, :category)
+        .where("user_followers.follower_id = ?", user.id)
+        .listable_topics
+        .visible
+        .order(created_at: :desc)
+
+    results = filter_opted_out_users(results)
+    results = Guardian.new(current_user).filter_allowed_categories(results)
+    results = results.limit(limit) if limit
+    results = results.where("topics.created_at < ?", created_before) if created_before
+    results = results.where("topics.created_at > ?", created_after) if created_after
+
+    results
+  end
+
   def self.filter_opted_out_users(relation)
     truthy_values = sanitize_sql(["?", HasCustomFields::Helpers::CUSTOM_FIELD_TRUE])
     if SiteSetting.default_allow_people_to_follow_me

plugin.rb

@@ -108,4 +108,17 @@ module ::Follow
     next if !new_record
     Follow::NotificationHandler.new(post, notified).handle
   end
+
+  filter_following_topics = ->(scope, username, guardian) do
+    user = User.find_by(username: username)
+
+    next scope if user.nil?
+    next scope.none if user.id != guardian.user.id && !guardian.user.staff?
+
+    topic_ids = UserFollower.topics_for(user, current_user: guardian.user).pluck(:id)
+
+    scope.where("topics.id IN (?)", topic_ids)
+  end
+
+  add_filter_custom_filter("following-feed", &filter_following_topics)
 end

spec/models/user_follower_spec.rb

@@ -188,4 +188,71 @@
       end
     end
   end
+
+  describe ".topics_for" do
+    it "does not show topics in PMs" do
+      Fabricate(:private_message_topic, user: followed)
+      topics = UserFollower.topics_for(follower, current_user: admin)
+      expect(topics.pluck(:id)).to be_blank
+    end
+
+    it "filters with created_before" do
+      topic_1 = Fabricate(:topic, user: followed, created_at: 1.day.ago)
+      topic_2 = Fabricate(:topic, user: followed, created_at: 2.day.ago)
+
+      topics = UserFollower.topics_for(follower, current_user: admin, created_before: 25.hours.ago)
+      expect(topics).to contain_exactly(topic_2)
+    end
+
+    it "filters with created_after" do
+      Fabricate(:topic, user: followed, created_at: 2.day.ago)
+      topic_2 = Fabricate(:topic, user: followed, created_at: 1.day.ago)
+
+      topics = UserFollower.topics_for(follower, current_user: admin, created_after: 25.hours.ago)
+      expect(topics).to contain_exactly(topic_2)
+    end
+
+    it "does not show unlisted topics" do
+      topic = Fabricate(:topic, user: followed)
+      topic.update_status("visible", false, Discourse.system_user)
+      topics = UserFollower.topics_for(follower, current_user: admin)
+      expect(topics.pluck(:id)).to be_blank
+    end
+
+    it "does not show topics in secured categories that current user does " \
+         "not have access to" do
+      Fabricate(:topic, user: followed, category: secure_category)
+      topics = UserFollower.topics_for(follower, current_user: follower)
+      expect(topics.pluck(:id)).to be_blank
+    end
+
+    it "does not show deleted topics" do
+      topic = Fabricate(:topic, user: followed)
+      topic.update!(deleted_at: 1.minute.ago)
+      topics = UserFollower.topics_for(follower, current_user: admin)
+      expect(topics.pluck(:id)).to be_blank
+    end
+
+    describe "it behaves like posts_for" do
+      it "brings topics the same way as posts_for" do
+        Fabricate(:post, user: followed)
+        topics = UserFollower.topics_for(follower, current_user: admin)
+        topic_ids_from_posts_for =
+          UserFollower.posts_for(follower, current_user: admin).map(&:topic_id)
+
+        expect(topics.pluck(:id)).to contain_exactly(*topic_ids_from_posts_for)
+      end
+
+      it "does not show repeated topics" do
+        topic = Fabricate(:topic, user: followed)
+        Fabricate.times(3, :post, user: followed, topic: topic)
+
+        topics = UserFollower.topics_for(follower, current_user: admin)
+        expect(topics.size).to eq(1)
+
+        posts = UserFollower.posts_for(follower, current_user: admin)
+        expect(posts.size).to eq(3)
+      end
+    end
+  end
 end

spec/requests/follow_controller_spec.rb

@@ -183,7 +183,7 @@ def response_topic_ids(response)
       expect(response.status).to eq(403)
     end
 
-    it "allows staff users to acess the follow posts feed of other users" do
+    it "allows staff users to access the follow posts feed of other users" do
       mod = Fabricate(:moderator)
       sign_in(mod)
       get "/follow/posts/#{user1.username}.json"
@@ -281,4 +281,68 @@ def response_topic_ids(response)
       expect(p["topic"]["posts_count"]).to eq(post_1.topic.posts_count)
     end
   end
+
+  describe "#filter" do
+    before do
+      ::Follow::Updater.new(user1, user2).watch_follow
+      ::Follow::Updater.new(user1, tl3).watch_follow
+    end
+
+    fab!(:post_5) { Fabricate(:post, user: user2, created_at: 20.hours.ago) }
+    fab!(:post_4) { Fabricate(:post, user: user2, created_at: 10.hours.ago) }
+    fab!(:post_3) { Fabricate(:post, user: user2, created_at: 5.hours.ago) }
+    fab!(:post_2) { Fabricate(:post, user: tl3, created_at: 3.hours.ago) }
+    fab!(:post_1) { Fabricate(:post, user: user2, topic: post_3.topic, created_at: 2.hours.ago) }
+    fab!(:post_by_unfollowed_user) { Fabricate(:post) }
+
+    it "allows users to see their own follow posts feed" do
+      sign_in(user1)
+      get "/follow/posts/#{user1.username}.json"
+      expect(response.status).to eq(200)
+      topic_ids_from_api = response.parsed_body["posts"].map { |t| t["topic_id"] }.uniq
+
+      get "/filter", params: { q: "following-feed:#{user1.username}", format: :json }
+      expect(response.status).to eq(200)
+      topic_ids_from_filter = response.parsed_body["topic_list"]["topics"].map { |t| t["id"] }.uniq
+
+      expect(topic_ids_from_api).to match_array(topic_ids_from_filter)
+    end
+
+    it "should not allow users to see other users follow posts feed" do
+      sign_in(user2)
+      get "/follow/posts/#{user1.username}.json"
+      expect(response.status).to eq(403)
+
+      get "/filter", params: { q: "following-feed:#{user1.username}", format: :json }
+      expect(response.parsed_body["topic_list"]["topics"]).to eq([])
+    end
+
+    it "allows staff users to access the follow posts feed of other users" do
+      user1_interacted_topics = [
+        post_1.topic.id,
+        post_2.topic.id,
+        post_3.topic.id,
+        post_4.topic.id,
+        post_5.topic.id,
+      ].uniq
+
+      mod = Fabricate(:moderator)
+      sign_in(mod)
+
+      get "/filter", params: { q: "following-feed:#{user1.username}", format: :json }
+      expect(response.status).to eq(200)
+      topic_ids_from_filter = response.parsed_body["topic_list"]["topics"].map { |t| t["id"] }.uniq
+
+      expect(topic_ids_from_filter).to match_array(user1_interacted_topics)
+
+      admin = Fabricate(:admin)
+      sign_in(admin)
+
+      get "/filter", params: { q: "following-feed:#{user1.username}", format: :json }
+      expect(response.status).to eq(200)
+      topic_ids_from_filter = response.parsed_body["topic_list"]["topics"].map { |t| t["id"] }.uniq
+
+      expect(topic_ids_from_filter).to match_array(user1_interacted_topics)
+    end
+  end
 end