Ruby on rails Rails:grapeapi-name错误：未初始化的常量API

我目前正在学习如何使用Rails。我遵循了本网站上的教程：

我将文件不放在lib文件夹中，而是放在app文件夹中，并按照教程中的说明编辑application.rb。其余代码与教程中的代码相同

在自定义错误格式化程序之前，我一直在完成此操作，但如果启动Rails服务器测试所有内容，则会出现以下错误：

                Exiting
E:/Users/Robert/Documents/Rubymine Projects/WarframeApi/config/routes.rb:3:in `block in <top (required)>': uninitialized constant API (NameError)
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/actionpack-4.1.8/lib/action_dispatch/routing/route_set.rb:337:in `instance_exec'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/actionpack-4.1.8/lib/action_dispatch/routing/route_set.rb:337:in `eval_block'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/actionpack-4.1.8/lib/action_dispatch/routing/route_set.rb:315:in `draw'
    from E:/Users/Robert/Documents/Rubymine Projects/WarframeApi/config/routes.rb:1:in `<top (required)>'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.1.8/lib/rails/application/routes_reloader.rb:40:in `block in load_paths'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.1.8/lib/rails/application/routes_reloader.rb:40:in `each'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.1.8/lib/rails/application/routes_reloader.rb:40:in `load_paths'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.1.8/lib/rails/application/routes_reloader.rb:16:in `reload!'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.1.8/lib/rails/application/routes_reloader.rb:26:in `block in updater'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/activesupport-4.1.8/lib/active_support/file_update_checker.rb:75:in `call'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/activesupport-4.1.8/lib/active_support/file_update_checker.rb:75:in `execute'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.1.8/lib/rails/application/routes_reloader.rb:27:in `updater'
    from C:in `execute_if_updated'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.1.8/lib/rails/application/finisher.rb:71:in `block in <module:Finisher>'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.1.8/lib/rails/initializable.rb:30:in `instance_exec'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.1.8/lib/rails/initializable.rb:30:in `run'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.1.8/lib/rails/initializable.rb:55:in `block in run_initializers'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/2.1.0/tsort.rb:226:in `block in tsort_each'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/2.1.0/tsort.rb:348:in `block (2 levels) in each_strongly_connected_component'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/2.1.0/tsort.rb:427:in `each_strongly_connected_component_from'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/2.1.0/tsort.rb:347:in `block in each_strongly_connected_component'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/2.1.0/tsort.rb:345:in `each'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/2.1.0/tsort.rb:345:in `call'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/2.1.0/tsort.rb:345:in `each_strongly_connected_component'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/2.1.0/tsort.rb:224:in `tsort_each'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/2.1.0/tsort.rb:205:in `tsort_each'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.1.8/lib/rails/initializable.rb:54:in `run_initializers'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.1.8/lib/rails/application.rb:300:in `initialize!'
    from E:/Users/Robert/Documents/Rubymine Projects/WarframeApi/config/environment.rb:5:in `<top (required)>'
    from E:/Users/Robert/Documents/Rubymine Projects/WarframeApi/config.ru:3:in `require'
    from E:/Users/Robert/Documents/Rubymine Projects/WarframeApi/config.ru:3:in `block in <main>'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/rack-1.5.2/lib/rack/builder.rb:55:in `instance_eval'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/rack-1.5.2/lib/rack/builder.rb:55:in `initialize'
    from E:/Users/Robert/Documents/Rubymine Projects/WarframeApi/config.ru:in `new'
    from E:/Users/Robert/Documents/Rubymine Projects/WarframeApi/config.ru:in `<main>'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/rack-1.5.2/lib/rack/builder.rb:49:in `eval'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/rack-1.5.2/lib/rack/builder.rb:49:in `new_from_string'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/rack-1.5.2/lib/rack/builder.rb:40:in `parse_file'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/rack-1.5.2/lib/rack/server.rb:277:in `build_app_and_options_from_config'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/rack-1.5.2/lib/rack/server.rb:199:in `app'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.1.8/lib/rails/commands/server.rb:50:in `app'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/rack-1.5.2/lib/rack/server.rb:314:in `wrapped_app'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.1.8/lib/rails/commands/server.rb:130:in `log_to_stdout'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.1.8/lib/rails/commands/server.rb:67:in `start'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.1.8/lib/rails/commands/commands_tasks.rb:81:in `block in server'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.1.8/lib/rails/commands/commands_tasks.rb:76:in `tap'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.1.8/lib/rails/commands/commands_tasks.rb:76:in `server'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.1.8/lib/rails/commands/commands_tasks.rb:40:in `run_command!'
    from C:/RailsInstaller/Ruby2.1.0/lib/ruby/gems/2.1.0/gems/railties-4.1.8/lib/rails/commands.rb:17:in `<top (required)>'
    from bin/rails:4:in `require'
    from bin/rails:4:in `<main>'

rake aborted!
NameError: uninitialized constant API
E:/Users/Robert/Documents/Rubymine Projects/WarframeApi/config/routes.rb:3:in `block in <top (required)>'
E:/Users/Robert/Documents/Rubymine Projects/WarframeApi/config/routes.rb:1:in `<top (required)>'
C:in `execute_if_updated'
E:/Users/Robert/Documents/Rubymine Projects/WarframeApi/config/environment.rb:5:in `<top (required)>'
Tasks: TOP => routes => environment
(See full trace by running task with --trace)

建议

---

下面编辑

Application.rb

require File.expand_path('../boot', __FILE__)

require 'rails/all'

# Require the gems listed in Gemfile, including any gems
# you've limited to :test, :development, or :production.
Bundler.require(*Rails.groups)

module WarframeApi
  class Application < Rails::Application

    # Api load config
    config.paths.add "app/api", glob: "**/*.rb"
    config.autoload_paths += Dir["#{Rails.root}/app/api/*"]
  end
end

api文件位于./app/api中（如教程中建议的备选位置）。以下是完整的文件结构：

• 应用程序
  • 原料药
    • root.rb
    • v1
      • 作者.rb
      • posts.rb
      • root.rb

---

将root.rb更改为：

class Root < Grape::API
  prefix 'api'
  mount V1::Root
  # mount V2::Root (next version)
end

---

Rails正在使用

模块api

时查找

api

文件夹。但是您已经在application.rb中自动加载了api文件夹，因此如果您保持root.rb不变，则需要另一个

api

文件夹。

我通过更改config/routes.rb解决了这个问题：

挂载V1:：Root=>“/”

到

---

mount Root=>“/api”

您只需要创建另一个目录结构

• 应用程序
  • 原料药
    • 原料药
      • v1
        • 作者.rb
        • posts.rb
        • root.rb
      • root.rb

---

请在此处添加application.rb。你把你的API模块放在哪里了？也添加你的routes.rb——与你的“API”路径相关的位。你添加了它，但它与教程中的相同。正如我已经写的：代码与教程中的代码完全相同。有关更多详细信息，请参阅更新的问题。这有点不同，但即使我将其更改为您的建议，也不起作用更新了我的答案，请参见。@Ruhrpottpatriot，您尝试过吗？更改目录结构确实有效。然而，这种结构不是我喜欢的。小问题：你指的是哪个root.rb？api中的那个，还是api/v1文件夹中的那个？因为更改api文件夹中的文件无效。

class Root < Grape::API
  prefix 'api'
  mount V1::Root
  # mount V2::Root (next version)
end

app > api > api > root.rb