ruby-on-rails - rails : Grape API - NameError: uninitialized constant API

Question

我目前正在学习如何使用 Rails。我遵循了本网站上的教程: http://funonrails.com/2014/03/building-restful-api-using-grape-in-rails/

我没有将文件放在 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了 application.rb。其余代码与教程中的相同。

我在自定义错误格式化程序之前完成了它，但是如果我启动 Rails 服务器来测试所有内容，我会收到以下错误:

                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>'

如果我不启动服务器而是调用 rake routes 我会收到以下错误:

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？

---

编辑如下

应用.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

路线.rb

Rails.application.routes.draw do
    mount API::Root => '/'
end

api 文件位于 ./app/api(如本教程中建议的替代位置)。这是完整性的文件结构:

• 应用程序
  • 应用程序接口(interface)
    • root.rb
    • v1
      • 作者.rb
      • posts.rb
      • root.rb

Answer 1

将你的 root.rb 改成这样:

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

或者，将您的目录结构更改为:

app > api > api > root.rb

Rails 正在寻找 api 文件夹，因为您正在使用 module API。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.