我的ActiveRecord模型的未定义方法“has_attached_file”

我完全按照https://github.com/thoughtbot/paperclip上的文档在我的应用程序中安装工具回形针以进行图像上传。 我目前正在使用gem’paperclip’,’〜> 5.0.0.beta1’。 完成迁移后,四列已正确添加到我的架构中:

t.string "picture_file_name" t.string "picture_content_type" t.integer "picture_file_size" t.datetime "picture_updated_at" 

因此,我的回形针应该正确安装。 但是,当我继续将以下两行添加到我的模型类中时:

  has_attached_file :picture, styles: { medium: "300*300>", thumb: "100*100" }, default_url: "/images/start_project3.jpg" validates_attachment_content_type :picture, content_type: /\Aimage\/.*\Z/ 

一切都破了。 我尝试在rails控制台中创建,搜索或与模型类相关的任何内容,它对我大吼大叫,出现以下错误:

 NoMethodError: undefined method `has_attached_file' for # 

我已经尝试了多个版本的回形针,从早期版本4.3.0到最新版本的回形针,但问题仍然存在。 我还在更改和迁移之间重新启动了我的服务器,但这并没有解决问题。 这是我执行的迁移:

 class AddAttachmentPictureToProjects < ActiveRecord::Migration def self.up change_table :projects do |t| t.attachment :picture end end def self.down remove_attachment :projects, :picture end end 

我现在完全迷失了该怎么做。 这是我的gem文件:

 source 'https://rubygems.org' # Bundle edge Rails instead: gem 'rails', github: 'rails/rails' gem 'rails', '4.2.7.1' # Use postgresql as the database for Active Record gem 'pg', '~> 0.15' # Use SCSS for stylesheets gem 'sass-rails', '~> 5.0' # Use Uglifier as compressor for JavaScript assets gem 'uglifier', '>= 1.3.0' # Use CoffeeScript for .coffee assets and views gem 'coffee-rails', '~> 4.1.0' # See https://github.com/rails/execjs#readme for more supported runtimes # gem 'therubyracer', platforms: :ruby # Use jquery as the JavaScript library gem 'jquery-rails' # Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder gem 'jbuilder', '~> 2.0' # bundle exec rake doc:rails generates the API under doc/api. gem 'sdoc', '~> 0.4.0', group: :doc # Use ActiveModel has_secure_password gem 'bcrypt', '~> 3.1.7' gem 'pry-rails' gem 'annotate' # Use Unicorn as the app server # gem 'unicorn' gem 'faker' # Use Capistrano for deployment # gem 'capistrano-rails', group: :development gem 'pg_search' gem 'paperclip', '~> 5.0.0.beta1' # gem "paperclip", :git => "git://github.com/thoughtbot/paperclip.git" # gem "paperclip", "~> 4.3" group :development, :test do # Call 'byebug' anywhere in the code to stop execution and get a debugger console gem 'byebug' gem 'faker' end group :development do # Access an IRB console on exception pages or by using  in views gem 'web-console', '~> 2.0' # Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring gem 'spring' end group :production do gem 'newrelic_rpm' gem 'rails_12factor' # error feedback end 

我不确定发生了什么。 我最终做了数据库回滚并再次重新迁移了迁移。 然后我退出了在后台运行的所有终端并重新启动了所有内容。 它现在正在运作。