API for apps to register for push notifications

app/controllers/api/v1/devices_controller.rb

@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+class Api::V1::DevicesController < ApiController
+  before_action -> { doorkeeper_authorize! :read }
+  before_action :require_user!
+
+  respond_to :json
+
+  def register
+    Device.where(account: current_account, registration_id: params[:registration_id]).first_or_create!(account: current_account, registration_id: params[:registration_id])
+    render_empty
+  end
+
+  def unregister
+    Device.where(account: current_account, registration_id: params[:registration_id]).delete_all
+    render_empty
+  end
+end

app/models/device.rb

@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class Device < ApplicationRecord
+  belongs_to :account
+
+  validates :account, :registration_id, presence: true
+end

app/services/notify_service.rb

@@ -10,6 +10,7 @@ class NotifyService < BaseService
 
     create_notification
     send_email if email_enabled?
+    send_push_notification
   rescue ActiveRecord::RecordInvalid
     return
   end
@@ -57,6 +58,10 @@ class NotifyService < BaseService
     NotificationMailer.send(@notification.type, @recipient, @notification).deliver_later
   end
 
+  def send_push_notification
+    PushNotificationWorker.perform_async(@notification.id)
+  end
+
   def email_enabled?
     @recipient.user.settings.notification_emails[@notification.type]
   end

app/services/send_push_notification_service.rb

@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+class SendPushNotificationService < BaseService
+  def call(notification)
+  	return if ENV['FCM_API_KEY'].blank?
+
+  	devices = Device.where(account: notification.account).pluck(:registration_id)
+  	fcm     = FCM.new(ENV['FCM_API_KEY'])
+
+  	response = fcm.send(devices, data: { notification_id: notification.id }, collapse_key: :notifications, priority: :high)
+  	handle_response(response)
+  end
+
+  private
+
+  def handle_response(response)
+    update_canonical_ids(response[:canonical_ids]) if response[:canonical_ids]
+    remove_bad_ids(response[:not_registered_ids])  if response[:not_registered_ids]
+  end
+
+  def update_canonical_ids(ids)
+  	ids.each { |pair| Device.find_by(registration_id: pair[:old]).update(registration_id: pair[:new]) }
+  end
+
+  def remove_bad_ids(bad_ids)
+  	Device.where(registration_id: bad_ids).delete_all
+  end
+end

app/workers/push_notification_worker.rb

@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+class PushNotificationWorker
+  include Sidekiq::Worker
+
+  def perform(notification_id)
+    SendPushNotificationService.new.call(Notification.find(notification_id))
+  rescue ActiveRecord::RecordNotFound
+    true
+  end
+end