(feat) backend for notifications preference system

app/controllers/api/notifications_controller.rb

@@ -15,14 +15,16 @@ class API::NotificationsController < API::ApiController
   def index
     loop do
       @notifications = current_user.notifications
+                                   .delivered_in_system(current_user)
                                    .includes(:attached_object)
                                    .page(params[:page])
-                                   .per(NOTIFICATIONS_PER_PAGE).order('created_at DESC')
+                                   .per(NOTIFICATIONS_PER_PAGE)
+                                   .order('created_at DESC')
       # we delete obsolete notifications on first access
       break unless delete_obsoletes(@notifications)
     end
     @totals = {
-      total: current_user.notifications.count,
+      total: current_user.notifications.delivered_in_system(current_user).count,
       unread: current_user.notifications.where(is_read: false).count
     }
     render :index
@@ -39,7 +41,7 @@ class API::NotificationsController < API::ApiController
       break unless delete_obsoletes(@notifications)
     end
     @totals = {
-      total: current_user.notifications.count,
+      total: current_user.notifications.delivered_in_system(current_user).count,
       unread: current_user.notifications.where(is_read: false).count
     }
     render :index
@@ -50,7 +52,7 @@ class API::NotificationsController < API::ApiController
                                  .where('is_read = false AND created_at >= :date', date: params[:last_poll])
                                  .order('created_at DESC')
     @totals = {
-      total: current_user.notifications.count,
+      total: current_user.notifications.delivered_in_system(current_user).count,
       unread: current_user.notifications.where(is_read: false).count
     }
     render :index

app/models/notification.rb

@@ -6,6 +6,17 @@ class Notification < ApplicationRecord
   belongs_to :receiver, polymorphic: true
   belongs_to :attached_object, polymorphic: true
 
+  # This scope filter a user's in system (push) notifications :
+  # It fetch his notifications where no notification preference is made,
+  # or if this preference specify that the user accepts in system notification
+  scope :delivered_in_system, lambda { |user|
+    left_outer_joins(notification_type: :notification_preferences)
+      .where(<<-SQL.squish, user.id)
+      (notification_preferences.user_id = ? AND notification_preferences.in_system IS TRUE)
+      OR notification_preferences.id IS NULL
+      SQL
+  }
+
   validates :receiver_id,
             :receiver_type,
             :attached_object_id,
@@ -33,6 +44,16 @@ class Notification < ApplicationRecord
     NotificationsMailer.send_mail_by(self).deliver_later if save
   end
 
+  def deliver_with_preferences(user, notification_type)
+    preference = NotificationPreference.find_by(notification_type: notification_type, user: user)
+
+    # Set as read if user do not want push notifications
+    self.is_read = true if preference && preference.in_system == false
+
+    # Save notification if user do not want email notifications ; else, deliver.
+    preference && preference.email == false ? save : deliver_later
+  end
+
   def get_meta_data(key)
     meta_data.try(:[], key.to_s)
   end

app/models/notification_preference.rb

@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+# Allow user to set their preferences for notifications (push and email)
+class NotificationPreference < ApplicationRecord
+  belongs_to :user
+  belongs_to :notification_type
+end

app/models/notification_type.rb

@@ -3,5 +3,7 @@
 # NotificationType defines the different types of Notification.
 class NotificationType < ApplicationRecord
   has_many :notifications, dependent: :destroy
+  has_many :notification_preferences, dependent: :destroy
+
   validates :name, uniqueness: true, presence: true
 end

app/models/user.rb

@@ -51,6 +51,7 @@ class User < ApplicationRecord
   has_many :proof_of_identity_refusals, dependent: :destroy
 
   has_many :notifications, as: :receiver, dependent: :destroy
+  has_many :notification_preferences, dependent: :destroy
 
   # fix for create admin user
   before_save do

app/services/notification_center.rb

@@ -4,14 +4,16 @@
 class NotificationCenter
   def self.call(type: nil, receiver: nil, attached_object: nil, meta_data: {})
     receiver = [receiver] unless receiver.respond_to?(:each)
+    notification_type = NotificationType.find_by(name: type)
+
     receiver.each do |user|
       Notification.new(
         meta_data: meta_data,
         attached_object: attached_object,
         receiver: user,
-        notification_type: NotificationType.find_by(name: type)
+        notification_type: notification_type
       )
-                  .deliver_later
+                  .deliver_with_preferences(user, notification_type)
     end
   end
 end

db/migrate/20230127100506_create_notification_preferences.rb

@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+# Create notification preferences : allow user to decide which type of notifications
+# they want to receive via push ('in system') or via email.
+class CreateNotificationPreferences < ActiveRecord::Migration[5.2]
+  def change
+    create_table :notification_preferences do |t|
+      t.references :user, index: true, foreign_key: true, null: false
+      t.references :notification_type, index: true, foreign_key: true, null: false
+      t.boolean :in_system, default: true
+      t.boolean :email, default: true
+
+      t.timestamps
+    end
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2023_01_26_160900) do
+ActiveRecord::Schema.define(version: 2023_01_27_100506) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "fuzzystrmatch"