chore: Add validation to prevent message flooding (#9254)

- Add a validation to limit messages created per minute to avoid message flooding cases.

app/models/message.rb

@@ -59,6 +59,7 @@ class Message < ApplicationRecord
   }.to_json.freeze
 
   before_validation :ensure_content_type
+  before_validation :prevent_message_flooding
   before_save :ensure_processed_message_content
   before_save :ensure_in_reply_to
 
@@ -227,6 +228,18 @@ class Message < ApplicationRecord
 
   private
 
+  def prevent_message_flooding
+    # Added this to cover the validation specs in messages
+    # We can revisit and see if we can remove this later
+    return if conversation.blank?
+
+    # there are cases where automations can result in message loops, we need to prevent such cases.
+    if conversation.messages.where('created_at >= ?', 1.minute.ago).count >= Limits.conversation_message_per_minute_limit
+      Rails.logger.error "Too many message: Account Id - #{account_id} : Conversation id - #{conversation_id}"
+      errors.add(:base, 'Too many messages')
+    end
+  end
+
   def ensure_processed_message_content
     text_content_quoted = content_attributes.dig(:email, :text_content, :quoted)
     html_content_quoted = content_attributes.dig(:email, :html_content, :quoted)

lib/limits.rb

@@ -4,4 +4,8 @@ module Limits
   URL_LENGTH_LIMIT = 2048 # https://stackoverflow.com/questions/417142
   OUT_OF_OFFICE_MESSAGE_MAX_LENGTH = 10_000
   GREETING_MESSAGE_MAX_LENGTH = 10_000
+
+  def self.conversation_message_per_minute_limit
+    ENV.fetch('CONVERSATION_MESSAGE_PER_MINUTE_LIMIT', '200').to_i
+  end
 end

spec/models/message_spec.rb

@@ -11,7 +11,7 @@ RSpec.describe Message do
   end
 
   describe 'length validations' do
-    let(:message) { create(:message) }
+    let!(:message) { create(:message) }
 
     context 'when it validates name length' do
       it 'valid when within limit' do
@@ -27,6 +27,17 @@ RSpec.describe Message do
         expect(message.errors[:processed_message_content]).to include('is too long (maximum is 150000 characters)')
         expect(message.errors[:content]).to include('is too long (maximum is 150000 characters)')
       end
+
+      it 'adds error in case of message flooding' do
+        with_modified_env 'CONVERSATION_MESSAGE_PER_MINUTE_LIMIT': '2' do
+          conversation = message.conversation
+          create(:message, conversation: conversation)
+          conv_new_message = build(:message, conversation: message.conversation)
+
+          expect(conv_new_message.valid?).to be false
+          expect(conv_new_message.errors[:base]).to eq(['Too many messages'])
+        end
+      end
     end
   end