add posts scope filter

app/controllers/posts_controller.rb

@@ -2,7 +2,7 @@ class PostsController < ApplicationController
   # GET /posts
   # GET /posts.json
   def index
-    @posts = Post.all
+    @posts = PostsQueryResolverService.call(query_params, current_user)
   end
 
   # GET /posts/1
@@ -14,7 +14,10 @@ class PostsController < ApplicationController
   # POST /posts
   # POST /posts.json
   def create
-    @post = Post.new(post_params)
+    @post = Post.new({
+      user: current_user,
+      **post_params
+    })
 
     if @post.save
       render :show, status: :created, location: @post
@@ -25,11 +28,11 @@ class PostsController < ApplicationController
 
   private
 
-  # Only allow a list of trusted parameters through.
+  def query_params
+    params.permit(:scope) || {}
+  end
+
   def post_params
-    {
-      user: current_user,
-      **params.require(:post).permit(:content, :quoted_post_id)
-    }
+    params.require(:post).permit(:content, :quoted_post_id)
   end
 end

app/services/posts_query_resolver_service.rb

@@ -0,0 +1,22 @@
+class PostsQueryResolverService
+  attr_reader :filter, :current_user
+
+  def initialize(filter, current_user)
+    @filter = filter
+    @current_user = current_user
+  end
+
+  def self.call(filter, current_user)
+    new(filter, current_user).call
+  end
+
+  def call
+    scope = Post.all
+
+    if filter[:scope] == 'follows' && current_user
+      scope = scope.by_user_follows(current_user)
+    end
+
+    scope
+  end
+end

db/seeds.rb

@@ -7,3 +7,4 @@ UserFollow.find_or_create_by(follower_id: geonizeli.id, followed_id: xpto.id)
 
 first_post = Post.find_or_create_by(content: 'Hello World!', user_id: xpto.id)
 Post.find_or_create_by(content: 'Hello World!', user_id: xpto.id, quoted_post_id: first_post.id)
+Post.find_or_create_by(content: 'Hello World!', user_id: geonizeli.id)

spec/requests/posts_spec.rb

@@ -1,17 +1,5 @@
 require 'rails_helper'
 
-# This spec was generated by rspec-rails when you ran the scaffold generator.
-# It demonstrates how one might use RSpec to test the controller code that
-# was generated by Rails when you ran the scaffold generator.
-#
-# It assumes that the implementation code is generated by the rails scaffold
-# generator. If you are using any extension libraries to generate different
-# controller code, this generated spec may or may not pass.
-#
-# It only uses APIs available in rails and/or rspec-rails. There are a number
-# of tools you can use to make these specs even more expressive, but we're
-# sticking to rails and rspec-rails APIs to keep things simple and stable.
-
 RSpec.describe "/posts", type: :request do
   let(:user) { create(:user) }
 
@@ -27,10 +15,6 @@ RSpec.describe "/posts", type: :request do
     }
   }
 
-  # This should return the minimal set of values that should be in the headers
-  # in order to pass any filters (e.g. authentication) defined in
-  # PostsController, or in your router and rack
-  # middleware. Be sure to keep this updated too.
   let(:valid_headers) {
     {
       Cookie: "user_id=#{user.id}"

spec/services/posts_query_resolver_serivce_spec.rb

@@ -0,0 +1,37 @@
+require 'rails_helper'
+
+RSpec.describe PostsQueryResolverService, type: :service do
+  context '#call' do
+    let(:current_user) { create(:user) }
+
+    context 'when without filter' do
+      it 'returns all posts' do
+        followed_user = create(:user)
+        create(:user_follow, follower_id: current_user.id, followed_id: followed_user.id)
+
+        post1 = create(:post, user_id: followed_user.id)
+        post2 = create(:post, user_id: followed_user.id)
+        post3 = create(:post)
+
+        expect(
+          described_class.call({}, current_user)
+        ).to eq([post1, post2, post3])
+      end
+    end
+
+    context 'when scoping by user follows' do
+      it 'returns only posts from user follows' do
+        followed_user = create(:user)
+        create(:user_follow, follower_id: current_user.id, followed_id: followed_user.id)
+
+        post1 = create(:post, user_id: followed_user.id)
+        post2 = create(:post, user_id: followed_user.id)
+        post3 = create(:post)
+
+        expect(
+          described_class.call({ scope: 'follows' }, current_user)
+        ).to eq([post1, post2])
+      end
+    end
+  end
+end