防止用户从他的最后4个密码中创建密码

Question

我正在mvc框架中工作，我想防止用户从最后4个密码中创建密码。

到目前为止，这是我所做的事情，实际上，我遵循的是github某人的代码，但似乎他没有提到encrypted_password_changed函数和encrypted_password函数。

密码历史记录表

class CreatePasswordHistories < ActiveRecord::Migration
  def self.up
    create_table(:password_histories) do |t|
      t.integer :user_id
      t.string  :encrypted_password
      t.timestamps
    end
  end

  def self.down
    drop_table :password_histories
  end
end

用户模型

class User < ApplicationRecord
  include ActiveModel::Validations

  has_many :password_histories
  after_save :store_digest
  validates :password, :unique_password => true

  private

  def store_digest
    if encrypted_password_changed?
      PasswordHistory.create(:user => self, :encrypted_password => encrypted_password)
    end
  end
end

自定义验证器

require 'bcrypt'
class UniquePasswordValidator < ActiveModel::EachValidator
  def validate_each(record, attribute, value)
    record.password_histories.each do |ph|
      bcrypt = ::BCrypt::Password.new(ph.encrypted_password)
      hashed_value = ::BCrypt::Engine.hash_secret([value, Devise.pepper].join, bcrypt.salt)
      record.errors[attribute] << "has been used previously." and return if hashed_value == ph.encrypted_password
    end
  end
end