在Rails 4中创建API - 未初始化的常量Api :: V1 :: UsersController

Question

对于个人项目，我想在Rails 4中创建Restful Web服务。

所以，我使用rails-api创建了我的第一个项目，并添加了以下代码：

在MyProject> config目录中的routes.rb

MyProject::Application.routes.draw do
    namespace :api, defaults: {format: 'json'} do
        namespace :v1 do
            resources :users
        end
    end
end

users_controller.rb在MyProject的>应用>控制器> API> V1>用户目录

module Api
    module V1
        class UsersController < ApplicationController
            def index
            end

            def create
            end

            def show
            end

            def update
            end

            def delete
            end
        end 
    end
end

当我使用命令行rails s启动rails服务器并转到此URL时： http://localhost:3000/api/v1/users/show我遇到此错误：

未初始化的常量Api :: V1 :: UsersController

Rails.root：/ Users / Jean / Development / MyProject

应用程序跟踪| 框架跟踪| 完全跟踪activesupport（4.0.4）lib / active_support / inflector / methods.rb：228：在const_get' activesupport (4.0.4) lib/active_support/inflector/methods.rb:228:in在constantize const_get' activesupport (4.0.4) lib/active_support/inflector/methods.rb:228:in块'activesupport（4.0。 4）lib / active_support / inflector / methods.rb：224：在each' activesupport (4.0.4) lib/active_support/inflector/methods.rb:224:in inject'activesupport（4.0.4）lib / active_support / inflector / methods.rb：224：在constantize' actionpack (4.0.4) lib/action_dispatch/routing/route_set.rb:76:in controller_reference'actionpack（4.0.4）lib / action_dispatch / routing / route_set.rb:66:in controller' actionpack (4.0.4) lib/action_dispatch/routing/route_set.rb:44:in调用'actionpack（4.0.4）lib / action_dispatch / journey / router.rb：71：在block in call' actionpack (4.0.4) lib/action_dispatch/journey/router.rb:59:in每个'actionpack（4.0.4）lib / action_dispatch / journey / router.rb：59：在call' actionpack (4.0.4) lib/action_dispatch/routing/route_set.rb:674:in电话'机架（1.5.2）lib / rack / etag.rb:23：在call' rack (1.5.2) lib/rack/conditionalget.rb:25:in call' rack (1.5.2) lib/rack/conditionalget.rb:25:in调用'rack（1.5.2）lib / rack / head.rb：11：在call' actionpack (4.0.4) lib/action_dispatch/middleware/params_parser.rb:27:in调用'activerecord（4.0.4）lib / active_record / query_cache.rb：36：在call' activerecord (4.0.4) lib/active_record/connection_adapters/abstract/connection_pool.rb:626:in调用'activerecord（4.0.4） ）lib / active_record / migration.rb：373：在call' actionpack (4.0.4) lib/action_dispatch/middleware/callbacks.rb:29:in块中调用'activesupport（4.0.4）lib / active_support / callbacks.rb ：373：in _run__4323212420903942114__call__callbacks' activesupport (4.0.4) lib/active_support/callbacks.rb:80:in run_callbacks'actionpack（4.0.4）lib / action_dispatch / middleware / callbacks.rb:27:in call' actionpack (4.0.4) lib/action_dispatch/middleware/reloader.rb:64:in调用'actionpack（4.0.4）lib / action_dispatch / middleware / remote_ip.rb：76：在call' actionpack (4.0.4) lib/action_dispatch/middleware/debug_exceptions.rb:17:in调用'actionpack（4.0.4）lib / action_dispatch / mi中 ddleware / show_exceptions.rb:30：在call' railties (4.0.4) lib/rails/rack/logger.rb:38:in call_app'railties（4.0.4）lib / rails / rack / logger.rb：20： in block in call' activesupport (4.0.4) lib/active_support/tagged_logging.rb:68:in block in tagged'activesupport（4.0.4）lib / active_support / tagged_logging.rb:26:in tagged' activesupport (4.0.4) lib/active_support/tagged_logging.rb:68:in标记为'railties（4.0.4）lib / rails / rack / logger.rb：20：在call' actionpack (4.0.4) lib/action_dispatch/middleware/request_id.rb:21:in呼叫'机架（1.5.2）lib / rack / runtime.rb：17：在call' activesupport (4.0.4) lib/active_support/cache/strategy/local_cache.rb:83:in呼叫'机架（ 1.5.2）lib / rack / lock.rb:17：在call' actionpack (4.0.4) lib/action_dispatch/middleware/static.rb:64:in调用'railties（4.0.4）lib / rails / engine中。 rb：511：在call' railties (4.0.4) lib/rails/application.rb:97:in呼叫'机架（1.5.2）lib / rack / lock.rb：17：在call' rack (1.5.2) lib/rack/content_length.rb:14:in调用'rack（1.5.2）lib / rack / handler / webrick.rb中： 60： service' /Users/Jean/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/webrick/httpserver.rb:138:in service'/Users/Jean/.rvm/rubies/ ruby-2.1.2 / lib / ruby​​ / 2.1.0 / webrick / httpserver.rb:94:in run' /Users/Jean/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/webrick/server.rb:295:in /Jean/ run' /Users/Jean/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/webrick/server.rb:295:in /rubies/ruby-2.1.2/lib/ruby/2.1.0/webrick run' /Users/Jean/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/webrick/server.rb:295:in块'

我发现Stackoverflow上有很多帖子有相同的错误，但答案并没有帮助我解决我的问题。

谢谢 ！

Answer 1

如果你有这条路：

MyProject> app> controllers> api> v1> users

控制器应该是class Api::V1::Users::UsersController如果这样：

MyProject> app> controllers> api> v1> users_controller.rb

然后是class Api::V1::UsersController

对于首字母缩写名称API::V1::UsersController而不是Api::V1::Users::UsersController使用inflectors：

在config/initializers/inflections.rb

 ActiveSupport::Inflector.inflections(:en) do |inflect|
   inflect.acronym 'API'
 end