用户模型补丁仅适用于少数请求答案

【问题标题】：User Model Patch works only for a few requests用户模型补丁仅适用于少数请求
【发布时间】：2012-06-18 19:31:01
【问题描述】：

我需要我的 Redmine 插件的补丁，以便为用户模型添加一个新的“has_many”关系。在我以开发模式启动 Rails 服务器后，它可以工作一段时间，但奇怪的是在几个请求后停止工作。

这是我的补丁：

require_dependency 'project'
require_dependency 'principal'
require_dependency 'user'

module UserPatch
  def self.included(base) 
    base.extend(ClassMethods)

    base.send(:include, InstanceMethods)

    # Same as typing in the class 
    base.class_eval do
      unloadable # Send unloadable so it will not be unloaded in development
      has_many :favourites

    end

  end

  module ClassMethods

  end

  module InstanceMethods
  end

end

User.send(:include, UserPatch)

这是错误日志：

NoMethodError (undefined method `favourites' for #<User:0x007f99cbc3d478>):
  activemodel (3.2.3) lib/active_model/attribute_methods.rb:407:in `method_missing'
  activerecord (3.2.3) lib/active_record/attribute_methods.rb:148:in `method_missing'
  plugins/redmine_asset_tracker/app/controllers/asset_types_controller.rb:20:in `index'
  actionpack (3.2.3) lib/action_controller/metal/implicit_render.rb:4:in `send_action'
  actionpack (3.2.3) lib/abstract_controller/base.rb:167:in `process_action'
  actionpack (3.2.3) lib/action_controller/metal/rendering.rb:10:in `process_action'
  actionpack (3.2.3) lib/abstract_controller/callbacks.rb:18:in `block in process_action'
  activesupport (3.2.3) lib/active_support/callbacks.rb:447:in `_run__2420136461919276817__process_action__3214240126008154381__callbacks'
  activesupport (3.2.3) lib/active_support/callbacks.rb:405:in `__run_callback'
  activesupport (3.2.3) lib/active_support/callbacks.rb:385:in `_run_process_action_callbacks'
  activesupport (3.2.3) lib/active_support/callbacks.rb:81:in `run_callbacks'
  actionpack (3.2.3) lib/abstract_controller/callbacks.rb:17:in `process_action'
  actionpack (3.2.3) lib/action_controller/metal/rescue.rb:29:in `process_action'
  actionpack (3.2.3) lib/action_controller/metal/instrumentation.rb:30:in `block in process_action'
  activesupport (3.2.3) lib/active_support/notifications.rb:123:in `block in instrument'
  activesupport (3.2.3) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
  activesupport (3.2.3) lib/active_support/notifications.rb:123:in `instrument'
  actionpack (3.2.3) lib/action_controller/metal/instrumentation.rb:29:in `process_action'
  actionpack (3.2.3) lib/action_controller/metal/params_wrapper.rb:205:in `process_action'
  activerecord (3.2.3) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
  actionpack (3.2.3) lib/abstract_controller/base.rb:121:in `process'
  actionpack (3.2.3) lib/abstract_controller/rendering.rb:45:in `process'
  actionpack (3.2.3) lib/action_controller/metal.rb:203:in `dispatch'
  actionpack (3.2.3) lib/action_controller/metal/rack_delegation.rb:14:in `dispatch'
  actionpack (3.2.3) lib/action_controller/metal.rb:246:in `block in action'
  actionpack (3.2.3) lib/action_dispatch/routing/route_set.rb:73:in `call'
  actionpack (3.2.3) lib/action_dispatch/routing/route_set.rb:73:in `dispatch'
  actionpack (3.2.3) lib/action_dispatch/routing/route_set.rb:36:in `call'
  journey (1.0.3) lib/journey/router.rb:68:in `block in call'
  journey (1.0.3) lib/journey/router.rb:56:in `each'
  journey (1.0.3) lib/journey/router.rb:56:in `call'
  actionpack (3.2.3) lib/action_dispatch/routing/route_set.rb:600:in `call'
  rack-openid (1.3.1) lib/rack/openid.rb:98:in `call'
  actionpack (3.2.3) lib/action_dispatch/middleware/best_standards_support.rb:17:in `call'
  rack (1.4.1) lib/rack/etag.rb:23:in `call'
  rack (1.4.1) lib/rack/conditionalget.rb:25:in `call'
  actionpack (3.2.3) lib/action_dispatch/middleware/head.rb:14:in `call'
  actionpack (3.2.3) lib/action_dispatch/middleware/params_parser.rb:21:in `call'
  actionpack (3.2.3) lib/action_dispatch/middleware/flash.rb:242:in `call'
  rack (1.4.1) lib/rack/session/abstract/id.rb:205:in `context'
  rack (1.4.1) lib/rack/session/abstract/id.rb:200:in `call'
  actionpack (3.2.3) lib/action_dispatch/middleware/cookies.rb:338:in `call'
  activerecord (3.2.3) lib/active_record/query_cache.rb:64:in `call'
  activerecord (3.2.3) lib/active_record/connection_adapters/abstract/connection_pool.rb:467:in `call'
  actionpack (3.2.3) lib/action_dispatch/middleware/callbacks.rb:28:in `block in call'
  activesupport (3.2.3) lib/active_support/callbacks.rb:405:in `_run__4577554638097020546__call__1559518111822758715__callbacks'
  activesupport (3.2.3) lib/active_support/callbacks.rb:405:in `__run_callback'
  activesupport (3.2.3) lib/active_support/callbacks.rb:385:in `_run_call_callbacks'
  activesupport (3.2.3) lib/active_support/callbacks.rb:81:in `run_callbacks'
  actionpack (3.2.3) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
  actionpack (3.2.3) lib/action_dispatch/middleware/reloader.rb:65:in `call'
  actionpack (3.2.3) lib/action_dispatch/middleware/remote_ip.rb:31:in `call'
  actionpack (3.2.3) lib/action_dispatch/middleware/debug_exceptions.rb:16:in `call'
  actionpack (3.2.3) lib/action_dispatch/middleware/show_exceptions.rb:56:in `call'
  railties (3.2.3) lib/rails/rack/logger.rb:26:in `call_app'
  railties (3.2.3) lib/rails/rack/logger.rb:16:in `call'
  actionpack (3.2.3) lib/action_dispatch/middleware/request_id.rb:22:in `call'
  rack (1.4.1) lib/rack/methodoverride.rb:21:in `call'
  rack (1.4.1) lib/rack/runtime.rb:17:in `call'
  activesupport (3.2.3) lib/active_support/cache/strategy/local_cache.rb:72:in `call'
  rack (1.4.1) lib/rack/lock.rb:15:in `call'
  actionpack (3.2.3) lib/action_dispatch/middleware/static.rb:62:in `call'
  railties (3.2.3) lib/rails/engine.rb:479:in `call'
  railties (3.2.3) lib/rails/application.rb:220:in `call'
  rack (1.4.1) lib/rack/content_length.rb:14:in `call'
  railties (3.2.3) lib/rails/rack/log_tailer.rb:14:in `call'
  rack (1.4.1) lib/rack/handler/webrick.rb:59:in `service'
  /Users/myth/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/1.9.1/webrick/httpserver.rb:138:in `service'
  /Users/myth/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/1.9.1/webrick/httpserver.rb:94:in `run'
  /Users/myth/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/1.9.1/webrick/server.rb:191:in `block in start_thread'

我哪里错了？

【问题讨论】：

您能否在生产环境中尝试一下（rails s -e production），看看您是否有相同的行为？如果不是，您看到的错误可能是开发中自动重新加载的结果。
它似乎工作正常。我如何使它也适用于我的开发模式？这种情况经常发生并且很烦人。

标签： ruby-on-rails metaprogramming ruby-on-rails-plugins redmine redmine-plugins

【解决方案1】：

试试这个：

module UserPatch
  def self.included(base) 
    base.extend(ClassMethods)
    base.send(:include, InstanceMethods)
    # Note the change below
    base.unloadable 
    base.has_many :favourites
  end

  module ClassMethods    
  end

  module InstanceMethods
  end

end

您可以在included 部分中的类上运行类方法。

【讨论】：

【解决方案2】：

会不会是您的模型被重新加载但这个扩展没有？如果您包含模型本身的扩展，会发生什么？

【讨论】：

您是否暗示要更新型号代码？我正在构建一个插件，无法直接更新模型。
我的错，错过了。您可以尝试在生产模式下运行（就像@AdrienCoquio 也建议的那样），这会给您相同的答案。
它在生产模式下工作。我如何在开发模式下修复它？这很烦人。

【解决方案3】：

由于这仅在开发环境中不起作用，因此在开发中重新加载类是一个问题。

在您的 config/environments/development.rb 中添加配置：

config.to_prepare do
  load 'user_patch.rb'
end

应确保为每个请求重新加载。

这样，您可能会惊讶于该模块可能在用户中多次包含，要修复它，您可以使用ActiveSupport::Concern。

有 2 个问题可能对您有所帮助：

【讨论】：

【解决方案4】：

您是否使用Passenger？如果你使用passenger，可能很难保证什么时候加载它，加载的对象被使用了多远等等。

我有类似的问题in this question 我无法得到答案。我也以类似的方式进行了全局变量初始化，但似乎不能保证工作。

我解决了我的问题，不依赖于方法外语句执行的时间/次数。

已经给出的答案可以避免部分问题，但就您使用Passenger而言，这并不容易，就我而言。

【讨论】：