Hartl Rails 教程第 8.46 章 NoMethodError [英] Hartl Rails Tutorial Chapter 8.46 NoMethodError

问题描述

我的一个测试在 Hartl 的 Rails 教程的第 8 章中收到以下错误.

one my my tests receiving the following error in Chapter 8 of Hartl's Rails Tutorial.

>  1) Error:
> UsersLoginTest#test_login_with_valid_information_followed_by_logout:
> NoMethodError: undefined method `forget' for #<Class:0x000000079be3b0>
>     app/helpers/sessions_helper.rb:30:in `forget'
>     app/helpers/sessions_helper.rb:37:in `log_out'
>     app/controllers/sessions_controller.rb:18:in `destroy'
>     test/integration/users_login_test.rb:40:in `block in <class:UsersLoginTest>'

我已经尝试完全按照教程中的方式复制和粘贴代码，但似乎并没有解决问题.

I have tried copying and pasting code exactly as it is in the tutorial, but it doesn't seem to be solving the issue.

这是我的会话助手

module SessionsHelper
  def log_in(user)
    session[:user_id] = user.id
  end

  def remember(user)
    user.remember
    cookies.permanent.signed[:user_id] = user.id
    cookies.permanent[:remember_token] = user.remember_token
  end

  def current_user
    if (user_id = session[:user_id])
      @current_user ||= User.find_by(id: user_id)
    elsif (user_id = cookies.signed[:user_id])
      user = User.find_by(id: user_id)

      if user && user.authenticated?(cookies[:remember_token])
        log_in user
        @current_user = user
      end
    end
  end


  def logged_in?
    !current_user.nil?
  end

  def forget(user)
    user.forget
    cookies.delete(:user_id)
    cookies.delete(:remember_token)
  end

  # Logs out the current user.
  def log_out
    forget(current_user)
    session.delete(:user_id)
    @current_user = nil
  end 
end

我的会话控制器在下面

class SessionsController < ApplicationController
  def new
  end

  def create
    user = User.find_by(email: params[:session][:email].downcase)

    if user && user.authenticate(params[:session][:password])
      log_in user
      remember user
      redirect_to user
    else
      flash.now[:danger] = 'Invalid email/password combination'
      render 'new'
    end
  end

  def destroy
    log_out if logged_in?
    redirect_to root_url
    end
  end

非常感谢任何建议！

推荐答案

在这里我们可以看到仔细查看错误消息的重要性.它说有一个无方法错误".好的.所以我们正在对用户做一些事情，但没有方法.用户是一个模型化的东西，所以让我们看看 app/models/user.rb:

Here we can see the importance of really looking closely at the error message. It says there is a "No Method Error". OK. So we're doing something with the Users and there's no method. A user is a modeled thing, so let's look at app/models/user.rb:

class User < ActiveRecord::Base
  attr_accessor :remember_token
  before_save { self.email = email.downcase }
  validates :name,  presence: true, length: { maximum: 50 }
  VALID_EMAIL_REGEX = /\A[\w+\-.]+@[a-z\d\-.]+\.[a-z]+\z/i
  validates :email, presence: true, length: { maximum: 255 },
                    format: { with: VALID_EMAIL_REGEX },
                    uniqueness: { case_sensitive: false }
  has_secure_password
  validates :password, presence: true, length: { minimum: 6 }

  # Returns the hash digest of the given string.
  def User.digest(string)
    cost = ActiveModel::SecurePassword.min_cost ? BCrypt::Engine::MIN_COST :
                                                  BCrypt::Engine.cost
    BCrypt::Password.create(string, cost: cost)
  end

  # Returns a random token.
 def User.new_token
    SecureRandom.urlsafe_base64
  end

  # Remembers a user in the database for use in persistent sessions.
  def remember
    self.remember_token = User.new_token
    update_attribute(:remember_digest, User.digest(remember_token))
  end

  # Returns true if the given token matches the digest.
  def authenticated?(remember_token)
    BCrypt::Password.new(remember_digest).is_password?(remember_token)
  end

  # Forgets a user.
  def forget
    update_attribute(:remember_digest, nil)
  end
end

我们看到最后创建了一个名为forget"的方法

we see that at the very end, there is a method being created called "forget"

def forget
  #something
end

这会为来自其他控制器和助手的调用打开方法，您已经在会话部分创建了这些方法.

That opens up the method to calls from other controllers and helpers, which you've already created in the Sessions section.

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