如何防止用户被保存在轨道上 ruby 中相关 model 的验证中？

Question

I have the following setup with the backend to a mobile app:

class User < ApplicationRecord
   has_many :mobile_device_infos
   ...
end

class MobileDeviceInfo < ApplicationRecord
   belongs_to :user
   ...
end

Every time the user logs in, a user device id is saved to mobile device info table, along with the last login time. A new device id will create a new record for the same user account. When a new user is created, then a search needs to be done via a validation that prevents the user from being saved if there are more than 2 duplicate accounts with the same device id where the last login time is less than one hour old. How can I create a validation that checks the mobile device info table each time a user is created that will prevent the user from being saved if there are more than 2 of the same device id?

I would imagine that I would need a validation on the MobileDeviceInfo table and accepts_nested_attibutes_for on the user model. How would I go about creating this type of validation?

Answer 1

possible when user login you should check if device already exist to prevent duplicates - MobileDeviceInfo.find_or_initialize_by(base_params) . Or you can add custom validator validates_with MobileDeviceInfoCustomValidator to user model.

app/validators/mobile_device_info_custom_validator.rb

# frozen_string_literal: true

class MobileDeviceInfoCustomValidator < ActiveModel::Validator
  def validate(record)
    # your custom logic to validate
    return if # valid_case_logic
    error = I18n.t('validators.errors.messages') #your error if needed
    record.errors.add(:mobile_device_info, error)
  end
end

also all validation in MobileDeviceInfo model should work throw nested attributes.