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在app/services中，我有一些课程，如Notification::Finder和Notification::Builder。

它们被放置为app/services/notification/builder.rb和app/services/notification/finder.rb。

还有一个Notification类作为模型，在app/models/notification.rb

autoload_path 配置为config.autoload_paths += %W(#{config.root}/app/services)

当我尝试加载Finder时，它可以工作：

Loading development environment (Rails 3.2.9)
[1] pry(main)> Notification::Finder
=> Notification::Finder

但是当我尝试 时Builder，我遇到了 rails 自动加载的问题：

Loading development environment (Rails 3.2.9)
[1] pry(main)> Notification::Builder
=> ActiveRecord::Associations::Builder

当常量名称（Builder）已经由其他命名空间定义时，它只是忽略我使用的命名空间，并ActiveRecord::Associations::Builder取而代之。

这是预期的行为，还是 Rails 错误？

更详细地说，const_missing方法 atactivesupport/dependencies.rb接收 aconst_name 'Builder'和nesting.inspect => 'nil'。

奇怪的是，当我使用常量化时，它会按预期解决：

Loading development environment (Rails 3.2.9)
[1] pry(main)> 'Notification::Builder'.constantize
=> Notification::Builder

（github 上的 Rails 问题：https ://github.com/rails/rails/issues/8726 ）

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2 回答 2

2

ActiveRecord::Associations::Builder 是 Rails 中的一个模块。如果你有一个 Notification::Builder，你可以询问它的类：

>> Notification::Builder
=> ActiveRecord::Associations::Builder
>> Notification::Builder.class
=> Module
>> Notification::Builder.ancestors
=> [ActiveRecord::Associations::Builder]

这是预期的行为吗？

是的

好的，那么……你有什么选择？

  • 您可以使用与 Builder 不同的术语。像工厂。或通知::NotificationBuilder

更多信息：
* http://www.rubydoc.info/docs/rails/3.1.1/ActiveRecord/Associations/Builder/Association
* http://apidock.com/rails/ActiveRecord/Associations/Builder

于 2013-01-03T18:04:46.593 回答
1

存在此问题是因为您使用 ActiveRecord 模型作为命名空间。在我看到根本原因之前，我通过一些实验创建了一个要点。

ActiveRecord模型包括ActiveRecord::Associations模块。由于您可以在包含模块时获取常量，因此现在也可以通过 AR 模型访问其中Builder定义的常量。Associations您将在模块中定义的每个类中获得此行为，这些模块包含在 AR 模型中：

1.9.3-p194 :010 > Post.ancestors
 => [Post(id: integer, title: string, published_at: datetime, created_at: datetime, updated_at: datetime), Post::GeneratedFeatureMethods, #<Module:0x007fec74dc33a0>, ActiveRecord::Base, ActiveRecord::Core, ActiveRecord::Store, ActiveRecord::Serialization, ActiveModel::Serializers::Xml, ActiveModel::Serializers::JSON, ActiveModel::Serialization, ActiveRecord::Reflection, ActiveRecord::Transactions, ActiveRecord::Aggregations, ActiveRecord::NestedAttributes, ActiveRecord::AutosaveAssociation, ActiveModel::SecurePassword, ActiveRecord::Associations, ActiveRecord::Timestamp, ActiveModel::Validations::Callbacks, ActiveRecord::Callbacks, ActiveRecord::AttributeMethods::Serialization, ActiveRecord::AttributeMethods::Dirty, ActiveModel::Dirty, ActiveRecord::AttributeMethods::TimeZoneConversion, ActiveRecord::AttributeMethods::PrimaryKey, ActiveRecord::AttributeMethods::Query, ActiveRecord::AttributeMethods::BeforeTypeCast, ActiveRecord::AttributeMethods::Write, ActiveRecord::AttributeMethods::Read, ActiveRecord::AttributeMethods, ActiveModel::AttributeMethods, ActiveRecord::Locking::Pessimistic, ActiveRecord::Locking::Optimistic, ActiveRecord::CounterCache, ActiveRecord::Validations, ActiveModel::Validations::HelperMethods, ActiveSupport::Callbacks, ActiveModel::Validations, ActiveRecord::Integration, ActiveModel::Conversion, ActiveRecord::AttributeAssignment, ActiveModel::ForbiddenAttributesProtection, ActiveModel::DeprecatedMassAssignmentSecurity, ActiveRecord::Sanitization, ActiveRecord::Scoping::Named, ActiveRecord::Scoping::Default, ActiveRecord::Scoping, ActiveRecord::Inheritance, ActiveRecord::ModelSchema, ActiveRecord::ReadonlyAttributes, ActiveRecord::Persistence, Object, PP::ObjectMixin, ActiveSupport::Dependencies::Loadable, V8::Conversion::Object, JSON::Ext::Generator::GeneratorMethods::Object, Kernel, BasicObject]

一种可能的解决方案是将模块用作命名空间。例如module Notifications.

于 2013-01-03T19:15:53.537 回答