rails 的命令不再工作

Question

我是 Rails 和一般编程的新手。我按照 YouTube 上的教程构建了一个应用程序。我完成了整个工作，然后开始摆弄 Ruby 和 Rails 版本。也许是一个错误......无论如何，我不能再让 Rails S 命令工作。下面粘贴的是我得到的错误。我欢迎您提出任何建议。

tom@linux:~/apps/BookReview$ rails s => 引导彪马 => Rails 5.2.0 应用程序开始开发 => 运行rails server -h 以获得更多启动选项 退出 /home/tom/apps/BookReview/config/environments/development.rb:3:in block in <top (required)>': uninitialized constant Paperclip (NameError) from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/railtie.rb:216:ininstance_eval' 来自/home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/railtie.rb:216:in configure' from /home/tom/apps/BookReview/config/environments/development.rb:1:in' 来自/home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/engine.rb:602:in block (2 levels) in <class:Engine>' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/engine.rb:601:ineach' 来自/home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/engine.rb:601:in block in <class:Engine>' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/initializable.rb:32:ininstance_exec' 来自 /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/initializable.rb:32:in run' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/initializable.rb:61:inblock in run_initializers ' 来自 /home/tom/.rbenv/versions/2.3.1/lib/ruby/2.3.0/tsort.rb:228:in block in tsort_each' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/2.3.0/tsort.rb:350:inblock (2 个级别) in each_strongly_connected_component' 来自/home/tom/.rbenv/versions/2.3.1/lib/ruby/2.3.0/tsort.rb:422:in block (2 levels) in each_strongly_connected_component_from' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/2.3.0/tsort.rb:431:ineach_strongly_connected_component_from' 来自/home/tom/.rbenv/versions/2.3.1/lib/ruby/2.3.0/tsort.rb:421:in block in each_strongly_connected_component_from' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/initializable.rb:50:ineach' 来自/home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/initializable.rb:50:in tsort_each_child' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/2.3.0/tsort.rb:415:incall' 来自 /home/tom/.rbenv/versions/2.3.1/lib/ruby/2.3.0/tsort.rb:415:in each_strongly_connected_component_from' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/2.3.0/tsort.rb:349:inblock in each_strongly_connected_component' 来自/home/tom/.rbenv/versions/2.3.1/lib/ruby/2.3.0/tsort.rb:347:in each' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/2.3.0/tsort.rb:347:incall' 来自/home/tom/.rbenv/versions/2.3.1/lib/ruby/2.3.0/tsort.rb:347:in each_strongly_connected_component' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/2.3.0/tsort.rb:226:intsort_each' 来自/home/tom/.rbenv/versions/2.3.1/lib/ruby/2.3.0/tsort.rb:205:in tsort_each' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/initializable.rb:60:inrun_initializers' 来自/home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/application.rb:361:in initialize!' from /home/tom/apps/BookReview/config/environment.rb:5:in' 来自 config.ru:3:in require_relative' from config.ru:3:inblock in ' 来自/home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rack-2.0.5/lib/rack/builder.rb:55:in instance_eval' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rack-2.0.5/lib/rack/builder.rb:55:ininitialize' 来自 config.ru:in new' from config.ru:in' 来自/home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rack-2.0.5/lib/rack/builder.rb:49:in eval' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rack-2.0.5/lib/rack/builder.rb:49:innew_from_string' 来自/home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rack-2.0.5/lib/rack/builder.rb:40:in parse_file' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rack-2.0.5/lib/rack/server.rb:319:inbuild_app_and_options_from_config' 来自/home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rack-2.0.5/lib/rack/server.rb:219:in app' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/commands/server/server_command.rb:27:inapp' 来自/home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rack-2.0.5/lib/rack/server.rb:354:in wrapped_app' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/commands/server/server_command.rb:89:inlog_to_stdout' 来自/home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/commands/server/server_command.rb:51:in @987654344 @block 正在执行' 来自/home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/commands/server/server_command.rb:142:in @987654345 @履行' 来自/home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/thor-0.20.0/lib/thor/command.rb:27:in run' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/thor-0.20.0/lib/thor/invocation.rb:126:ininvoke_command' 来自/home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/thor-0.20.0/lib/thor.rb:387:in dispatch' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/command/base.rb:65:inperform' 来自/home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/command.rb:46:in invoke' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.2.0/lib/rails/commands.rb:18:in' 来自 /home/tom/apps/BookReview/bin/rails:9:in require' from /home/tom/apps/BookReview/bin/rails:9:in' 来自/home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/spring-2.0.2/lib/spring/client/rails.rb:28:in load' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/spring-2.0.2/lib/spring/client/rails.rb:28:incall ' 来自/home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/spring-2.0.2/lib/spring/client/command.rb:7:in call' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/spring-2.0.2/lib/spring/client.rb:30:inrun ' 来自/home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/spring-2.0.2/bin/spring:49:in <top (required)>' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/spring-2.0.2/lib/spring/binstub.rb:31:inload' 来自/home/tom/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/spring-2.0.2/lib/spring/binstub.rb:31:in <top (required)>' from /home/tom/.rbenv/versions/2.3.1/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:68:inrequire' 来自/home/tom/.rbenv/versions/2.3.1/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:68:in require' from /home/tom/apps/BookReview/bin/spring:15:in' 从 bin/rails:3:in load' from bin/rails:3:in'

Answer 1

在您的 Gemfile 中包含回形针 gem（如果尚未添加）。

gem "paperclip", git: "git://github.com/thoughtbot/paperclip.git"

之后运行bundle install