Question

在我的应用程序中，我可以发布不同类型的帖子。所以我有想法将Single Table Inheritance纳入其中：

class Post < ActiveRecord::Base
  has_many :comments
end

class TextPostValidator < ActiveModel::Validator
  def validate(record)
    if record.title.nil? and record.body.nil?
      record.errors[:base] << "Either title or body is necessary"
    end
  end
end

class TextPost < Post
  validates_with TextPostValidator
end

class ImagePost < Post
  validates :image_url, :presence => true
end

class VideoPost < Post
  validates :video_code, :presence => true
  validates :video_service, :presence => true
end

class LinkPost < Post
  validates :link_url, :presence => true
end

当我现在在PostsController：

中执行此操作时

def new_text
  @post = TextPost.new
end

def new_image
  @post = ImagePost.new
end

def new_video
  @post = VideoPost.new
end

def new_link
  @post = LinkPost.new
end

我收到此错误：

uninitialized constant PostsController::TextPost

似乎我对Rails的内部工作方式了解不足以找出原因。

加成来自rails console：

irb(main):009:0* ActiveRecord::Base.subclasses
=> [Post(id: integer, title: string, body: text, video_service: string, video_code: string, image_url: string, link_url: string, ooc: boolean, nsfw: boolean, allow_comment: boolean, type: string, created_at: datetime, updated_at: datetime),
TextPost(id: integer, title: string, body: text, video_service: string, video_code: string, image_url: string, link_url: string, ooc: boolean, nsfw: boolean, allow_comment: boolean, type: string, created_at: datetime, updated_at: datetime),
ImagePost(id: integer, title: string, body: text, video_service: string, video_code: string, image_url: string, link_url: string, ooc: boolean, nsfw: boolean, allow_comment: boolean, type: string, created_at: datetime, updated_at: datetime),
VideoPost(id: integer, title: string, body: text, video_service: string, video_code: string, image_url: string, link_url: string, ooc: boolean, nsfw: boolean, allow_comment: boolean, type: string, created_at: datetime, updated_at: datetime)
LinkPost(id: integer, title: string, body: text, video_service: string, video_code: string, image_url: string, link_url: string, ooc: boolean, nsfw: boolean, allow_comment: boolean, type: string, created_at: datetime, updated_at: datetime)]

好吧。

Answer 1

路由错误导致未初始化的常量错误。尝试转到routes.rb文件并提供单数和复数资源。

资源：发布和资源：帖子

Answer 2

来自：http://www.hackido.com/2009/03/quick-tip-solve-uninitialized-constant.html

“事实证明，在Ruby on Rails的最新版本中出现的主要变化中，还有一些小的变化。其中一个是应用程序控制器不再被称为application.rb现在它被称为as application_controller.rb。

实际上，要解决此问题，只需重命名该文件即可。或者，正如Liam在下面的评论中指出的那样，运行：“

rake rails：update

Rails：未初始化的常量PostsController :: TextPost

2 个答案: