sample_rails_tailwind/app/models/user.rb

class User < ApplicationRecord
  attr_accessor :remember_token, :activation_token, :reset_token
  # before_save { self.email = email.downcase }
  # before_save { email.downcase! }
  before_save   :downcase_email
  before_create :create_activation_digest
  validates :name, presence: true, length: { maximum: 50 }
  VALID_EMAIL_REGEX = /\A[\w+\-.]+@[a-z\d\-]+(\.[a-z\d\-]+)*\.[a-z]+\z/i
  validates :email, presence: true, length: { maximum: 255 },
            format: { with: VALID_EMAIL_REGEX },
            uniqueness:  true
  has_secure_password
  validates :password, presence: true, length: { minimum: 6 }, allow_nil: true

  def User.digest(string)
    cost = ActiveModel::SecurePassword.min_cost ? BCrypt::Engine::MIN_COST :
             BCrypt::Engine.cost
    BCrypt::Password.create(string, cost: cost)
  end

  def User.new_token
    SecureRandom.urlsafe_base64
  end

  def remember
    self.remember_token = User.new_token
    update_attribute(:remember_digest, User.digest(remember_token))
    remember_digest
  end

  # 返回一个会话令牌,防止会话劫持
  # 简单起见,直接使用记忆令牌
  def session_token
    remember_digest || remember
  end

  class << self
    def digest(string)
      cost  = ActiveModel::SecurePassword.min_cost ? BCrypt::Engine::MIN_COST :
                                                      BCrypt::Engine.cost
      BCrypt::Password.create(string, cost: cost)
    end

    def new_token
      SecureRandom.urlsafe_base64
    end
  end

  # powered by metaprogramming
  def authenticated?(attribute, token)
    digest = send("#{attribute}_digest")
    return false if digest.nil?
    BCrypt::Password.new(digest).is_password?(token)
  end

  def forget
    update_attribute(:remember_digest, nil)
  end

  def activate
    # update_attribute(:activated, true)
    # update_attribute(:activated_at, Time.zone.now)
    update_columns(activated: true, activated_at: Time.zone.now)
  end

  def send_activation_email
    UserMailer.account_activation(self).deliver_now
  end

  def create_reset_digest
    self.reset_token = User.new_token
    update_columns(reset_digest: User.digest(reset_token),
                   reset_send_at: Time.zone.now)
  end

  def send_password_reset_email
    UserMailer.password_reset(self).deliver_now
  end

  def password_reset_expired?
    reset_send_at < 2.hours.ago
  end

  private

  def downcase_email
    # self.email = email.downcase
    email.downcase!
  end

  def create_activation_digest
    self.activation_token = User.new_token
    self.activation_digest = User.digest(activation_token)
  end
end