Question

我经常需要抛出自定义（错误）错误。就像由于参数不匹配而无法找到资源时。

我更喜欢抛出现有错误，或抛出从现有错误继承的错误。这样，我不会引入已经定义的错误类，并且可以完美地使用（DRY）。但它也允许保持措辞和风格相同，通过继承和简单地改变一两个字来澄清与原始错误的差异。

例如：

Foo.new
Foo.some_external_id = nil
Foo.fetch_external_resource
# => InvalidOptions: Calling Foo#fetch_external_resource with nil is invalid

我很确定已经定义了这样的错误。事实上，在通过多行代码阅读后，我发现我的MongoID驱动程序有Mongoid::Errors::InvalidOptions: Calling Document#find with nil is invalid。

Ruby Core和Ruby on Rails中是否有可用的错误类列表？有没有办法为您当前的项目获得这样的列表？

重新使用和/或继承现有错误是否很聪明，或者我应该维护自己的自定义设置？

Answer 1

虽然这个列表可能会改变，但最好仍然使用Ryan的解决方案，Rails 4的列表（仅限Rails类而不是其他宝石）：

AbstractController::ActionNotFound
AbstractController::DoubleRenderError
AbstractController::Error
AbstractController::Helpers::ClassMethods::MissingHelperError
ActionController::ActionControllerError
ActionController::BadRequest
ActionController::InvalidAuthenticityToken
ActionController::MethodNotAllowed
ActionController::MissingFile
ActionController::NotImplemented
ActionController::ParameterMissing
ActionController::RedirectBackError
ActionController::RenderError
ActionController::RoutingError
ActionController::SessionOverflowError
ActionController::UnknownController
ActionController::UnknownFormat
ActionController::UnknownHttpMethod
ActionController::UnpermittedParameters
ActionController::UrlGenerationError
ActionDispatch::Cookies::CookieOverflow
ActionDispatch::IllegalStateError
ActionDispatch::Journey::Router::RoutingError
ActionDispatch::ParamsParser::ParseError
ActionDispatch::RemoteIp::IpSpoofAttackError
ActionDispatch::Session::SessionRestoreError
ActionView::Helpers::NumberHelper::InvalidNumberError
ActiveModel::ForbiddenAttributesError
ActiveModel::MissingAttributeError
ActiveRecord::ActiveRecordError
ActiveRecord::AdapterNotFound
ActiveRecord::AdapterNotSpecified
ActiveRecord::AssociationTypeMismatch
ActiveRecord::AttributeAssignmentError
ActiveRecord::ConfigurationError
ActiveRecord::ConnectionNotEstablished
ActiveRecord::ConnectionTimeoutError
ActiveRecord::DangerousAttributeError
ActiveRecord::DeleteRestrictionError
ActiveRecord::DuplicateMigrationNameError
ActiveRecord::DuplicateMigrationVersionError
ActiveRecord::EagerLoadPolymorphicError
ActiveRecord::HasAndBelongsToManyAssociationForeignKeyNeeded
ActiveRecord::HasManyThroughAssociationNotFoundError
ActiveRecord::HasManyThroughAssociationPointlessSourceTypeError
ActiveRecord::HasManyThroughAssociationPolymorphicSourceError
ActiveRecord::HasManyThroughAssociationPolymorphicThroughError
ActiveRecord::HasManyThroughCantAssociateNewRecords
ActiveRecord::HasManyThroughCantAssociateThroughHasOneOrManyReflection
ActiveRecord::HasManyThroughCantDissociateNewRecords
ActiveRecord::HasManyThroughNestedAssociationsAreReadonly
ActiveRecord::HasManyThroughSourceAssociationNotFoundError
ActiveRecord::HasOneThroughCantAssociateThroughCollection
ActiveRecord::IllegalMigrationNameError
ActiveRecord::ImmutableRelation
ActiveRecord::InvalidForeignKey
ActiveRecord::InverseOfAssociationNotFoundError
ActiveRecord::IrreversibleMigration
ActiveRecord::MultiparameterAssignmentErrors
ActiveRecord::NestedAttributes::TooManyRecords
ActiveRecord::PendingMigrationError
ActiveRecord::PreparedStatementInvalid
ActiveRecord::ReadOnlyAssociation
ActiveRecord::ReadOnlyRecord
ActiveRecord::RecordInvalid
ActiveRecord::RecordNotDestroyed
ActiveRecord::RecordNotFound
ActiveRecord::RecordNotSaved
ActiveRecord::RecordNotUnique
ActiveRecord::Rollback
ActiveRecord::SerializationTypeMismatch
ActiveRecord::StaleObjectError
ActiveRecord::StatementInvalid
ActiveRecord::SubclassNotFound
ActiveRecord::Tasks::DatabaseAlreadyExists
ActiveRecord::Tasks::DatabaseNotSupported
ActiveRecord::ThrowResult
ActiveRecord::TransactionIsolationError
ActiveRecord::Transactions::TransactionError
ActiveRecord::UnknownAttributeError
ActiveRecord::UnknownMigrationVersionError
ActiveRecord::UnknownPrimaryKey
ActiveRecord::WrappedDatabaseException
ActiveSupport::JSON::Encoding::CircularReferenceError
ActiveSupport::MessageVerifier::InvalidSignature
ActiveSupport::SafeBuffer::SafeConcatError
ActiveSupport::XMLConverter::DisallowedType

Answer 2

这里有一个非常合适的解决方案：http://www.ruby-forum.com/topic/158088

由于这个问题没有答案，但是在Google搜索结果的顶部，我决定将Frederick Cheung的解决方案包含在rake任务中，然后在此处发布。

将以下内容放在 lib / tasks / exceptions.rake

中

namespace :exceptions do
  task :list => :environment do
    exceptions = []

    ObjectSpace.each_object(Class) do |k|
      exceptions << k if k.ancestors.include?(Exception)
    end

    puts exceptions.sort { |a,b| a.to_s <=> b.to_s }.join("\n")
  end
end

使用以下命令运行：

bundle exec rake exceptions:list

如果你仍在使用Rails 2，或者没有使用Bundler，请不要使用bundle exec

此列表可能已足够，但并非详尽无遗。例如，ActiveResource定义了几个例外，例如ActiveResource::ConnectionError和ActiveResource::TimeoutError，这些例外在我运行此任务时不会出现。也许其他人可以告诉我为什么。

Answer 3

Rails thanks to ActiveSupport中提供了一个较短的选项：

puts Exception.descendants.sort_by(&:name)

您还可以查看来源，看看他们是如何处理的。

获取现有Rails错误类的列表以供重用/继承

3 个答案: