我正在线上的rails教程书,当我转到
http://localhost:3000/时,我收到以下错误消息
“uninitialized constant ApplicationRecord”
class User < ApplicationRecord
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,length: { maximum: 255 },
这是我的application.html.erb文件：
<!DOCTYPE html>
<html>
<head>
<title><%= full_title(yield(:title)) %></title>
<%= stylesheet_link_tag "application",media: "all","data-turbolinks-track" => true %>
<%= javascript_include_tag "application","data-turbolinks-track" => true %>
<%= csrf_Meta_tags %>
<%= render 'layouts/shim' %>
</head>
<body>
<%= render 'layouts/header' %>
<div class="container">
<% flash.each do |message_type,message| %>
<div class="alert alert-<%= message_type %>"><%= message %></div>
<% end %>
<%= yield %>
<%= render 'layouts/footer' %>
<%= debug(params) if Rails.env.development? %>
</div>
</body>
</html>
和我的user.rb文件：
class User < ApplicationRecord
attr_accessor :remember_token
before_save { self.email = email.downcase }
validates :name,format: { with: VALID_EMAIL_REGEX },uniqueness: { case_sensitive: false }
has_secure_password
validates :password,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)
return false if remember_digest.nil?
BCrypt::Password.new(remember_digest).is_password?(remember_token)
end
# Forgets a user.
def forget
update_attribute(:remember_digest,nil)
end
end
解决方法
看来你正在使用Rails 5教程,但是使用Rails 4.在Rails 5中,所有模型都继承自ApplicationRecord,而来自ActiveRecord :: Base的Rails 4
立即修复：
class User < ActiveRecord::Base ... end
长期修复,切换到Rails 5并学习Rails 5