feat: add meta deletion callback endpoint

app/controllers/webhooks/facebook_controller.rb

@@ -0,0 +1,48 @@
+class Webhooks::FacebookController < ActionController::API
+  class InvalidDigestError < StandardError; end
+
+  def process_deletion
+    signed_request = params['signed_request']
+    payload = parse_fb_signed_request(signed_request)
+    id_to_process = payload['user_id']
+
+    set_processing
+    Webhooks::MetaDeleteJob.perform_later(id_to_process)
+    status_url = "#{app_url_base}/meta/delete-status/#{id_to_process}"
+
+    render json: { status_url: status_url, code: id_to_process }, status: :ok
+  rescue InvalidDigestError
+    render json: { error: 'Invalid signature' }, status: :unprocessable_entity
+  end
+
+  private
+
+  def set_processing
+    # we use this key to check if the deletion is completed or not
+    # Once the key is gone, we know the deletion is completed
+    # And we can show as such
+    key = format(::Redis::Alfred::META_DELETE_PROCESSING, id: id_to_process)
+    ::Redis::Alfred.set(key, true)
+  end
+
+  def app_url_base
+    ENV.fetch('FRONTEND_URL', nil)
+  end
+
+  def parse_fb_signed_request(signed_request)
+    encoded_signature, payload = signed_request.split('.', 2)
+
+    decoded_signature = Base64.urlsafe_decode64(encoded_signature)
+    decoded_payload = JSON.parse(Base64.urlsafe_decode64(payload))
+
+    expected_signature = OpenSSL::HMAC.digest('sha256', app_secret, payload)
+
+    raise InvalidDigestError if decoded_signature != expected_signature
+
+    decoded_payload
+  end
+
+  def app_secret
+    GlobalConfigService.load('FB_APP_SECRET', '')
+  end
+end

app/jobs/webhooks/meta_delete_job.rb

@@ -0,0 +1,44 @@
+class Webhooks::MetaDeleteJob < ApplicationJob
+  queue_as :low
+
+  attr_reader :id_to_process
+
+  def perform(id_to_process)
+    @id_to_process = id_to_process
+
+    delete_channel_if_present
+    delete_contact_if_present
+
+    unset_processing
+  end
+
+  private
+
+  def unset_processing
+    key = format(::Redis::Alfred::META_DELETE_PROCESSING, id: id_to_process)
+    ::Redis::Alfred.del(key)
+  end
+
+  def delete_channel_if_present
+    channel = Channel::FacebookPage.find_by(page_id: id_to_process)
+    return unless channel
+
+    inbox = channel.inbox
+    inbox.destroy
+  end
+
+  def remove_contact_if_present
+    contact_inbox = ContactInbox.find_by(source_id: id_to_process)
+    return unless contact_inbox
+
+    contact = contact_inbox.contact
+    contact.update!(
+      name: 'Deleted User',
+      email: nil,
+      phone_number: nil,
+      identifier: nil,
+      additional_attributes: {},
+      custom_attributes: {}
+    )
+  end
+end

config/routes.rb

@@ -448,6 +448,7 @@ Rails.application.routes.draw do
   post 'webhooks/whatsapp/:phone_number', to: 'webhooks/whatsapp#process_payload'
   get 'webhooks/instagram', to: 'webhooks/instagram#verify'
   post 'webhooks/instagram', to: 'webhooks/instagram#events'
+  post 'webhooks/facebook/delete', to: 'webhooks/facebook#process_deletion'
 
   namespace :twitter do
     resource :callback, only: [:show]

lib/redis/redis_keys.rb

@@ -41,4 +41,7 @@ module Redis::RedisKeys
   IG_MESSAGE_MUTEX = 'IG_MESSAGE_CREATE_LOCK::%<sender_id>s::%<ig_account_id>s'.freeze
   SLACK_MESSAGE_MUTEX = 'SLACK_MESSAGE_LOCK::%<conversation_id>s::%<reference_id>s'.freeze
   EMAIL_MESSAGE_MUTEX = 'EMAIL_CHANNEL_LOCK::%<inbox_id>s'.freeze
+
+  ## Meta deletion flags
+  META_DELETE_PROCESSING = 'META_DELETE_PROCESSING::%<id>s'.freeze
 end