Push notifications background job for Post

app/jobs/create_push_notifications_job.rb

@@ -0,0 +1,11 @@
+class CreatePushNotificationsJob < ActiveJob::Base
+  queue_as :default
+
+  def perform(event_id:)
+    event = ::Event.find_by_id(event_id)
+
+    raise 'A valid Event must be provided' unless event
+
+    ::PushNotifications::Creator.new(event: event).create!
+  end
+end

app/models/push_notification.rb

@@ -0,0 +1,6 @@
+class PushNotification < ActiveRecord::Base
+  belongs_to :event, foreign_key: 'event_id'
+  belongs_to :device_token, foreign_key: 'device_token_id'
+
+  validates :event, :device_token, presence: true
+end

app/services/persister/post_persister.rb

@@ -10,6 +10,7 @@ def save
       ::ActiveRecord::Base.transaction do
         post.save!
         create_save_event!
+        enqueue_push_notification_job!
         post
       end
     rescue ActiveRecord::RecordInvalid => _exception
@@ -20,6 +21,7 @@ def update_attributes(params)
       ::ActiveRecord::Base.transaction do
         post.update_attributes!(params)
         create_update_event!
+        enqueue_push_notification_job!
         post
       end
     rescue ActiveRecord::RecordInvalid => _exception
@@ -28,12 +30,18 @@ def update_attributes(params)
 
     private
 
+    attr_accessor :event
+
     def create_save_event!
-      ::Event.create! action: :created, post: post
+      @event = ::Event.create! action: :created, post: post
     end
 
     def create_update_event!
-      ::Event.create! action: :updated, post: post
+      @event = ::Event.create! action: :updated, post: post
+    end
+
+    def enqueue_push_notification_job!
+      CreatePushNotificationsJob.perform_later(event_id: event.id)
     end
   end
 end

app/services/push_notifications/creator.rb

@@ -0,0 +1,22 @@
+module PushNotifications
+  class Creator
+    # Given an Event it will create as many PushNotification resources
+    # necessary as the resource associated to the Event will require.
+    #
+    # @param [Hash] event: <Event>
+    def initialize(event:)
+      @event = event
+    end
+
+    def create!
+      event_notifier = EventNotifierFactory.new(event: event).build
+      event_notifier.device_tokens.each do |device_token|
+        PushNotification.create!(event: event, device_token: device_token)
+      end
+    end
+
+    private
+
+    attr_accessor :event
+  end
+end

app/services/push_notifications/event_notifier/post.rb

@@ -0,0 +1,26 @@
+module PushNotifications
+  module EventNotifier
+    class Post
+      def initialize(event:)
+        @event = event
+        @post = event.post
+      end
+
+      # Conditions for Post:
+      #
+      # We need to notify all the users that:
+      #  - are members of the Post's organization
+      #  - have a DeviceToken associated
+      #
+      # @return [<DeviceToken>]
+      def device_tokens
+        organization = post.organization
+        DeviceToken.where(user_id: organization.user_ids)
+      end
+
+      private
+
+      attr_accessor :event, :post
+    end
+  end
+end

app/services/push_notifications/event_notifier_factory.rb

@@ -0,0 +1,17 @@
+module PushNotifications
+  class EventNotifierFactory
+    def initialize(event:)
+      @event = event
+    end
+
+    def build
+      return EventNotifier::Post.new(event: event) if event.post_id
+
+      raise 'The resource associated to the Event is not supported'
+    end
+
+    private
+
+    attr_accessor :event
+  end
+end

config/environments/test.rb

@@ -44,4 +44,7 @@
 
   # Avoid seeing all that stuff in tests
   config.log_level = :warn
+
+  # ActiveJob configuration
+  config.active_job.queue_adapter = :test
 end

db/migrate/20180524143938_create_push_notifications.rb

@@ -0,0 +1,14 @@
+class CreatePushNotifications < ActiveRecord::Migration
+  def change
+    create_table :push_notifications do |t|
+      t.references :event, null: false
+      t.references :device_token, null: false
+      t.datetime   :processed_at
+
+      t.timestamps null: false
+    end
+
+    add_foreign_key :push_notifications, :events
+    add_foreign_key :push_notifications, :device_tokens
+  end
+end

db/migrate/20180529144243_change_index_on_events.rb

@@ -0,0 +1,11 @@
+class ChangeIndexOnEvents < ActiveRecord::Migration
+  def change
+    remove_index :events, :post_id
+    remove_index :events, :member_id
+    remove_index :events, :transfer_id
+
+    add_index :events, :post_id, where: 'post_id IS NOT NULL'
+    add_index :events, :member_id, where: 'member_id IS NOT NULL'
+    add_index :events, :transfer_id, where: 'transfer_id IS NOT NULL'
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20180525141138) do
+ActiveRecord::Schema.define(version: 20180529144243) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -85,9 +85,9 @@
     t.datetime "updated_at"
   end
 
-  add_index "events", ["member_id"], name: "index_events_on_member_id", unique: true, where: "(member_id IS NOT NULL)", using: :btree
-  add_index "events", ["post_id"], name: "index_events_on_post_id", unique: true, where: "(post_id IS NOT NULL)", using: :btree
-  add_index "events", ["transfer_id"], name: "index_events_on_transfer_id", unique: true, where: "(transfer_id IS NOT NULL)", using: :btree
+  add_index "events", ["member_id"], name: "index_events_on_member_id", where: "(member_id IS NOT NULL)", using: :btree
+  add_index "events", ["post_id"], name: "index_events_on_post_id", where: "(post_id IS NOT NULL)", using: :btree
+  add_index "events", ["transfer_id"], name: "index_events_on_transfer_id", where: "(transfer_id IS NOT NULL)", using: :btree
 
   create_table "members", force: :cascade do |t|
     t.integer  "user_id"
@@ -158,6 +158,14 @@
   add_index "posts", ["tags"], name: "index_posts_on_tags", using: :gin
   add_index "posts", ["user_id"], name: "index_posts_on_user_id", using: :btree
 
+  create_table "push_notifications", force: :cascade do |t|
+    t.integer  "event_id",        null: false
+    t.integer  "device_token_id", null: false
+    t.datetime "processed_at"
+    t.datetime "created_at",      null: false
+    t.datetime "updated_at",      null: false
+  end
+
   create_table "transfers", force: :cascade do |t|
     t.integer  "post_id"
     t.text     "reason"
@@ -215,4 +223,6 @@
   add_foreign_key "events", "members", name: "events_member_id_fkey"
   add_foreign_key "events", "posts", name: "events_post_id_fkey"
   add_foreign_key "events", "transfers", name: "events_transfer_id_fkey"
+  add_foreign_key "push_notifications", "device_tokens"
+  add_foreign_key "push_notifications", "events"
 end

spec/fabricators/device_token_fabricator.rb

@@ -0,0 +1,2 @@
+Fabricator(:device_token) do
+end

spec/fabricators/event_fabricator.rb

@@ -0,0 +1,2 @@
+Fabricator(:event) do
+end

spec/jobs/create_push_notifications_job_spec.rb

@@ -0,0 +1,31 @@
+require 'spec_helper'
+
+RSpec.describe CreatePushNotificationsJob, type: :job do
+  describe '#perform' do
+    context 'with an Event that doesn\'t exist' do
+      let(:event_id) { nil }
+
+      it 'raises an error' do
+        expect {
+          described_class.new.perform(event_id: event_id)
+        }.to raise_error 'A valid Event must be provided'
+      end
+    end
+
+    context 'with an Event that does exist' do
+      let(:post) { Fabricate(:post) }
+      let(:event) { Fabricate(:event, post: post, action: :created) }
+      let(:event_id) { event.id }
+
+      it 'calls the PushNotification creator' do
+        creator = instance_double(::PushNotifications::Creator)
+        expect(::PushNotifications::Creator).to receive(:new)
+          .with(event: event)
+          .and_return(creator)
+        expect(creator).to receive(:create!)
+
+        described_class.new.perform(event_id: event_id)
+      end
+    end
+  end
+end

spec/models/push_notification_spec.rb

@@ -0,0 +1,16 @@
+require 'spec_helper'
+
+RSpec.describe PushNotification do
+  describe 'Validations' do
+    it { is_expected.to validate_presence_of(:event) }
+    it { is_expected.to validate_presence_of(:device_token) }
+  end
+
+  describe 'Associations' do
+    it { is_expected.to belong_to(:event).with_foreign_key('event_id') }
+    it { is_expected.to belong_to(:device_token).with_foreign_key('device_token_id') }
+
+    it { is_expected.to have_db_column(:event_id) }
+    it { is_expected.to have_db_column(:device_token_id) }
+  end
+end

spec/services/persister/post_persister_spec.rb

@@ -1,6 +1,6 @@
 require 'spec_helper'
 
-describe Persister::PostPersister do
+RSpec.describe Persister::PostPersister do
   let(:organization) { Fabricate(:organization) }
   let(:user) { Fabricate(:user) }
   let(:category) { Fabricate(:category) }
@@ -14,30 +14,57 @@
     )
   end
   let(:persister) { ::Persister::PostPersister.new(post) }
+  let(:event) { Fabricate.build(:event, id: 27) }
 
   describe '#save' do
-    before { persister.save }
-
     it 'saves the post' do
+      persister.save
+
       expect(post).to be_persisted
     end
 
-    # TODO: write better expectation
     it 'creates an event' do
-      expect(Event.where(post_id: post.id).first.action).to eq('created')
+      expect(::Event).to receive(:create!).with(action: :created, post: post).and_return(event)
+
+      persister.save
+    end
+
+    context 'background job' do
+      before do
+        allow(::Event).to receive(:create!).and_return(event)
+      end
+
+      it 'enqueues a CreatePushNotificationsJob background job' do
+        expect {
+          persister.save
+        }.to enqueue_job(CreatePushNotificationsJob).with(event_id: 27)
+      end
     end
   end
 
   describe '#update_attributes' do
-    before { persister.update_attributes(title: 'New title') }
-
     it 'updates the resource attributes' do
+      persister.update_attributes(title: 'New title')
+
       expect(post.title).to eq('New title')
     end
 
-    # TODO: write better expectation
     it 'creates an event' do
-      expect(Event.where(post_id: post.id).first.action).to eq('updated')
+      expect(::Event).to receive(:create!).with(action: :updated, post: post).and_return(event)
+
+      persister.update_attributes(title: 'New title')
+    end
+
+    context 'background job' do
+      before do
+        allow(::Event).to receive(:create!).and_return(event)
+      end
+
+      it 'enqueues a CreatePushNotificationsJob background job' do
+        expect {
+          persister.update_attributes(title: 'New title')
+        }.to enqueue_job(CreatePushNotificationsJob).with(event_id: 27)
+      end
     end
   end
 end

spec/services/push_notifications/creator_spec.rb

@@ -0,0 +1,25 @@
+require 'spec_helper'
+
+RSpec.describe PushNotifications::Creator do
+  let(:user) { Fabricate(:user) }
+  let!(:device_token) { Fabricate(:device_token, user: user, token: 'aloha') }
+  let(:organization) { Fabricate(:organization) }
+  let(:post) { Fabricate(:post, organization: organization, user: user) }
+  let(:event) { Fabricate.build(:event, post: post, action: :created) }
+  let(:creator) { described_class.new(event: event) }
+
+  before do
+    organization.members.create(user: user)
+  end
+
+  describe '#create!' do
+    it 'creates as many PushNotification resources as needed' do
+      expect(PushNotification).to receive(:create!).with(
+        event: event,
+        device_token: device_token
+      ).once
+
+      creator.create!
+    end
+  end
+end