ruby-on-rails - 如果 config.cache_classes = true，Rails 找不到模块

Question

我有一个 gem，它通过 routes.rb 作为引擎安装在我的 rails 应用程序中& Gemfile .以下是重要的部分:

应用程序' gem 文件

source 'https://rubygems.org'

gem 'rails', '3.2.9'
gem 'mysql2'


group :assets do
  gem 'sass-rails'
  gem 'coffee-rails'
end
gem 'jquery-rails'
gem "common_client", path: "../common-client"

应用程序 路线.rb

mount CommonClient::Engine => "", :as => 'shared'

gem 的 路线.rb

get '/register' => 'session#new_registration'

gem session Controller

require 'common_client/session_controller_base'

class SessionController < ApplicationController

  include CommonClient::SessionControllerBase
end

gem session Controller 库

module CommonClient

  module SessionControllerBase

  def new_registration
      #some code goes here
  end
end

这在开发中工作得很好，rails 能够找到 CommonClient::SessionController & 执行 new_registration每当访客点击 /register 时采取行动路线。但在生产中，rails 无法找到 CommonClient::SessionController & 产生以下错误:

$ RAILS_ENV=production rails s
=> Booting WEBrick
=> Rails 3.2.9 application starting in production on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
[2012-12-09 03:27:29] INFO  WEBrick 1.3.1
[2012-12-09 03:27:29] INFO  ruby 1.9.3 (2012-10-12) [x86_64-linux]
[2012-12-09 03:27:29] INFO  WEBrick::HTTPServer#start: pid=4248 port=3000
Started GET "/" for 127.0.0.1 at 2012-12-09 03:28:17 +0530
Processing by WelcomeController#index as HTML
Redirected to localhost:3000/register
Filter chain halted as :check_credentials rendered or redirected
Completed 302 Found in 267ms (ActiveRecord: 0.0ms)
Started GET "/register" for 127.0.0.1 at 2012-12-09 03:28:18 +0530

ActionController::RoutingError (uninitialized constant CommonClient::SessionController):
  vendor/bundles/ruby/1.9.1/gems/activesupport-3.2.9/lib/active_support/inflector/methods.rb:230:in `block in constantize'
  vendor/bundles/ruby/1.9.1/gems/activesupport-3.2.9/lib/active_support/inflector/methods.rb:229:in `each'
  vendor/bundles/ruby/1.9.1/gems/activesupport-3.2.9/lib/active_support/inflector/methods.rb:229:in `constantize'
  vendor/bundles/ruby/1.9.1/gems/actionpack-3.2.9/lib/action_dispatch/routing/route_set.rb:69:in `controller_reference'
  vendor/bundles/ruby/1.9.1/gems/actionpack-3.2.9/lib/action_dispatch/routing/route_set.rb:54:in `controller'
  vendor/bundles/ruby/1.9.1/gems/actionpack-3.2.9/lib/action_dispatch/routing/route_set.rb:32:in `call'
  vendor/bundles/ruby/1.9.1/gems/journey-1.0.4/lib/journey/router.rb:68:in `block in call'
  vendor/bundles/ruby/1.9.1/gems/journey-1.0.4/lib/journey/router.rb:56:in `each'
  vendor/bundles/ruby/1.9.1/gems/journey-1.0.4/lib/journey/router.rb:56:in `call'
  vendor/bundles/ruby/1.9.1/gems/actionpack-3.2.9/lib/action_dispatch/routing/route_set.rb:601:in `call'
  vendor/bundles/ruby/1.9.1/gems/railties-3.2.9/lib/rails/engine.rb:479:in `call'
  vendor/bundles/ruby/1.9.1/gems/railties-3.2.9/lib/rails/railtie/configurable.rb:30:in `method_missing'
  vendor/bundles/ruby/1.9.1/gems/journey-1.0.4/lib/journey/router.rb:68:in `block in call'
  vendor/bundles/ruby/1.9.1/gems/journey-1.0.4/lib/journey/router.rb:56:in `each'
  vendor/bundles/ruby/1.9.1/gems/journey-1.0.4/lib/journey/router.rb:56:in `call'
  vendor/bundles/ruby/1.9.1/gems/actionpack-3.2.9/lib/action_dispatch/routing/route_set.rb:601:in `call'
  vendor/bundles/ruby/1.9.1/gems/actionpack-3.2.9/lib/action_dispatch/middleware/best_standards_support.rb:17:in `call'
  vendor/bundles/ruby/1.9.1/gems/rack-1.4.1/lib/rack/etag.rb:23:in `call'
  vendor/bundles/ruby/1.9.1/gems/rack-1.4.1/lib/rack/conditionalget.rb:25:in `call'
  vendor/bundles/ruby/1.9.1/gems/actionpack-3.2.9/lib/action_dispatch/middleware/head.rb:14:in `call'
  vendor/bundles/ruby/1.9.1/gems/actionpack-3.2.9/lib/action_dispatch/middleware/params_parser.rb:21:in `call'
  vendor/bundles/ruby/1.9.1/gems/actionpack-3.2.9/lib/action_dispatch/middleware/flash.rb:242:in `call'
  vendor/bundles/ruby/1.9.1/gems/rack-1.4.1/lib/rack/session/abstract/id.rb:205:in `context'
  vendor/bundles/ruby/1.9.1/gems/rack-1.4.1/lib/rack/session/abstract/id.rb:200:in `call'
  vendor/bundles/ruby/1.9.1/gems/actionpack-3.2.9/lib/action_dispatch/middleware/cookies.rb:341:in `call'
  vendor/bundles/ruby/1.9.1/gems/activerecord-3.2.9/lib/active_record/query_cache.rb:64:in `call'
  vendor/bundles/ruby/1.9.1/gems/activerecord-3.2.9/lib/active_record/connection_adapters/abstract/connection_pool.rb:479:in `call'
  vendor/bundles/ruby/1.9.1/gems/actionpack-3.2.9/lib/action_dispatch/middleware/callbacks.rb:28:in `block in call'
  vendor/bundles/ruby/1.9.1/gems/activesupport-3.2.9/lib/active_support/callbacks.rb:405:in `_run__4296103602150594596__call__1936882885794917979__callbacks'
  vendor/bundles/ruby/1.9.1/gems/activesupport-3.2.9/lib/active_support/callbacks.rb:405:in `__run_callback'
  vendor/bundles/ruby/1.9.1/gems/activesupport-3.2.9/lib/active_support/callbacks.rb:385:in `_run_call_callbacks'
  vendor/bundles/ruby/1.9.1/gems/activesupport-3.2.9/lib/active_support/callbacks.rb:81:in `run_callbacks'
  vendor/bundles/ruby/1.9.1/gems/actionpack-3.2.9/lib/action_dispatch/middleware/callbacks.rb:27:in `call'
  vendor/bundles/ruby/1.9.1/gems/actionpack-3.2.9/lib/action_dispatch/middleware/remote_ip.rb:31:in `call'
  vendor/bundles/ruby/1.9.1/gems/actionpack-3.2.9/lib/action_dispatch/middleware/debug_exceptions.rb:16:in `call'
  vendor/bundles/ruby/1.9.1/gems/actionpack-3.2.9/lib/action_dispatch/middleware/show_exceptions.rb:56:in `call'
  vendor/bundles/ruby/1.9.1/gems/railties-3.2.9/lib/rails/rack/logger.rb:32:in `call_app'
  vendor/bundles/ruby/1.9.1/gems/railties-3.2.9/lib/rails/rack/logger.rb:16:in `block in call'
  vendor/bundles/ruby/1.9.1/gems/activesupport-3.2.9/lib/active_support/tagged_logging.rb:22:in `tagged'
  vendor/bundles/ruby/1.9.1/gems/railties-3.2.9/lib/rails/rack/logger.rb:16:in `call'
  vendor/bundles/ruby/1.9.1/gems/actionpack-3.2.9/lib/action_dispatch/middleware/request_id.rb:22:in `call'
  vendor/bundles/ruby/1.9.1/gems/rack-1.4.1/lib/rack/methodoverride.rb:21:in `call'
  vendor/bundles/ruby/1.9.1/gems/rack-1.4.1/lib/rack/runtime.rb:17:in `call'
  vendor/bundles/ruby/1.9.1/gems/activesupport-3.2.9/lib/active_support/cache/strategy/local_cache.rb:72:in `call'
  vendor/bundles/ruby/1.9.1/gems/rack-1.4.1/lib/rack/lock.rb:15:in `call'
  vendor/bundles/ruby/1.9.1/gems/rack-cache-1.2/lib/rack/cache/context.rb:136:in `forward'
  vendor/bundles/ruby/1.9.1/gems/rack-cache-1.2/lib/rack/cache/context.rb:245:in `fetch'
  vendor/bundles/ruby/1.9.1/gems/rack-cache-1.2/lib/rack/cache/context.rb:185:in `lookup'
  vendor/bundles/ruby/1.9.1/gems/rack-cache-1.2/lib/rack/cache/context.rb:66:in `call!'
  vendor/bundles/ruby/1.9.1/gems/rack-cache-1.2/lib/rack/cache/context.rb:51:in `call'
  vendor/bundles/ruby/1.9.1/gems/railties-3.2.9/lib/rails/engine.rb:479:in `call'
  vendor/bundles/ruby/1.9.1/gems/railties-3.2.9/lib/rails/application.rb:223:in `call'
  vendor/bundles/ruby/1.9.1/gems/rack-1.4.1/lib/rack/content_length.rb:14:in `call'
  vendor/bundles/ruby/1.9.1/gems/railties-3.2.9/lib/rails/rack/log_tailer.rb:17:in `call'
  vendor/bundles/ruby/1.9.1/gems/rack-1.4.1/lib/rack/handler/webrick.rb:59:in `service'
  /home/gaurish/.rvm/rubies/ruby-1.9.3-p286-perf/lib/ruby/1.9.1/webrick/httpserver.rb:138:in `service'
  /home/gaurish/.rvm/rubies/ruby-1.9.3-p286-perf/lib/ruby/1.9.1/webrick/httpserver.rb:94:in `run'
  /home/gaurish/.rvm/rubies/ruby-1.9.3-p286-perf/lib/ruby/1.9.1/webrick/server.rb:191:in `block in start_thread'


^C[2012-12-09 03:42:57] INFO  going to shutdown ...
[2012-12-09 03:42:57] INFO  WEBrick::HTTPServer#start done.
Exiting

现在，
这是有趣的部分。这些错误在生产中消失了，当我在 production.rb 中禁用代码缓存时，应用程序工作得很好.通过设置

config.cache_classes = false

这一切都让我好奇，

为什么 rails 可以CommonClient::SessionController在开发环境中但不在生产环境中？

如何设置config.cache_classes = false让它在生产中工作？和rails可以找到CommonClient::SessionController之前无法做到的

当 rails 找到 CommonClient::SessionController 时我需要做什么除了禁用代码缓存和在每个请求上重新加载所有代码的丑陋黑客之外？

最后，我已尽力解释，但仍有一些不清楚或需要更多信息。请发表评论。谢谢

Answer 1

我怀疑这与加载顺序有关。在开发模式下(当 cache_classes 为 false 时)，Rails 会在每次请求时加载所有可卸载的类。这发生在框架的其余部分已初始化之后。

相比之下，在生产模式下，所有内容都是一次性加载的，因此您的 CommonClient 可能在 Rails 堆栈的其他部分之前加载，然后被 Rails 加载隐藏。 Valery 关于 ActiveSupport 钩子(Hook)的建议是一个很好的建议——CommonClient railtie 是什么样的？您可以修改 gem 的 railtie 以在 ActionController 加载后加载 Controller ，这应该提供更类似于 Rails 的开发模式加载行为的行为。