为什么Rails 4.2 +响应者一直告诉我向Gemfile添加响应者？
我正在将Rails 4.1.8应用程序（也使用rails-api~> 0.3.1）升级到4.2.0.rc2，并希望保留respond_withfunction。 我已经在Gemfile中添加了responders器，但是当我bin/rake spec ，我得到：
/Users/sloveless/.gem/ruby/2.1.0/gems/actionpack-4.2.0.rc2/lib/action_controller/metal/mime_responds.rb:10:in `respond_to': The controller-level `respond_to' feature has been extracted to the `responders` gem. Add it to your Gemfile to continue using this feature: (NoMethodError) gem 'responders', '~> 2.0' Consult the Rails upgrade guide for details. from /Users/sloveless/Development/twilight/app/controllers/application_controller.rb:6:in `' from /Users/sloveless/Development/twilight/app/controllers/application_controller.rb:1:in `' from /Users/sloveless/.gem/ruby/2.1.0/gems/activesupport-4.2.0.rc2/lib/active_support/dependencies.rb:274:in `require' from /Users/sloveless/.gem/ruby/2.1.0/gems/activesupport-4.2.0.rc2/lib/active_support/dependencies.rb:274:in `block in require' from /Users/sloveless/.gem/ruby/2.1.0/gems/activesupport-4.2.0.rc2/lib/active_support/dependencies.rb:240:in `load_dependency' from /Users/sloveless/.gem/ruby/2.1.0/gems/activesupport-4.2.0.rc2/lib/active_support/dependencies.rb:274:in `require' from /Users/sloveless/.gem/ruby/2.1.0/gems/activesupport-4.2.0.rc2/lib/active_support/dependencies.rb:360:in `require_or_load' from /Users/sloveless/.gem/ruby/2.1.0/gems/activesupport-4.2.0.rc2/lib/active_support/dependencies.rb:494:in `load_missing_constant' from /Users/sloveless/.gem/ruby/2.1.0/gems/activesupport-4.2.0.rc2/lib/active_support/dependencies.rb:184:in `const_missing' from /Users/sloveless/Development/twilight/app/controllers/zone_maps_controller.rb:1:in `' from /Users/sloveless/.gem/ruby/2.1.0/gems/activesupport-4.2.0.rc2/lib/active_support/dependencies.rb:274:in `require' from /Users/sloveless/.gem/ruby/2.1.0/gems/activesupport-4.2.0.rc2/lib/active_support/dependencies.rb:274:in `block in require' from /Users/sloveless/.gem/ruby/2.1.0/gems/activesupport-4.2.0.rc2/lib/active_support/dependencies.rb:240:in `load_dependency' from /Users/sloveless/.gem/ruby/2.1.0/gems/activesupport-4.2.0.rc2/lib/active_support/dependencies.rb:274:in `require' from /Users/sloveless/.gem/ruby/2.1.0/gems/activesupport-4.2.0.rc2/lib/active_support/dependencies.rb:360:in `require_or_load' from /Users/sloveless/.gem/ruby/2.1.0/gems/activesupport-4.2.0.rc2/lib/active_support/dependencies.rb:494:in `load_missing_constant' from /Users/sloveless/.gem/ruby/2.1.0/gems/activesupport-4.2.0.rc2/lib/active_support/dependencies.rb:184:in `const_missing' from /Users/sloveless/Development/twilight/spec/controllers/zone_maps_controller_spec.rb:3:in `' from /Users/sloveless/.gem/ruby/2.1.0/gems/activesupport-4.2.0.rc2/lib/active_support/dependencies.rb:268:in `load' from /Users/sloveless/.gem/ruby/2.1.0/gems/activesupport-4.2.0.rc2/lib/active_support/dependencies.rb:268:in `block in load' from /Users/sloveless/.gem/ruby/2.1.0/gems/activesupport-4.2.0.rc2/lib/active_support/dependencies.rb:240:in `load_dependency' from /Users/sloveless/.gem/ruby/2.1.0/gems/activesupport-4.2.0.rc2/lib/active_support/dependencies.rb:268:in `load' from /Users/sloveless/.gem/ruby/2.1.0/gems/rspec-core-3.1.7/lib/rspec/core/configuration.rb:1105:in `block in load_spec_files' from /Users/sloveless/.gem/ruby/2.1.0/gems/rspec-core-3.1.7/lib/rspec/core/configuration.rb:1105:in `each' from /Users/sloveless/.gem/ruby/2.1.0/gems/rspec-core-3.1.7/lib/rspec/core/configuration.rb:1105:in `load_spec_files' from /Users/sloveless/.gem/ruby/2.1.0/gems/rspec-core-3.1.7/lib/rspec/core/runner.rb:96:in `setup' from /Users/sloveless/.gem/ruby/2.1.0/gems/rspec-core-3.1.7/lib/rspec/core/runner.rb:84:in `run' from /Users/sloveless/.gem/ruby/2.1.0/gems/rspec-core-3.1.7/lib/rspec/core/runner.rb:69:in `run' from /Users/sloveless/.gem/ruby/2.1.0/gems/rspec-core-3.1.7/lib/rspec/core/runner.rb:37:in `invoke' from /Users/sloveless/.gem/ruby/2.1.0/gems/rspec-core-3.1.7/exe/rspec:4:in `' from /Users/sloveless/.gem/ruby/2.1.0/gems/activesupport-4.2.0.rc2/lib/active_support/dependencies.rb:268:in `load' from /Users/sloveless/.gem/ruby/2.1.0/gems/activesupport-4.2.0.rc2/lib/active_support/dependencies.rb:268:in `block in load' from /Users/sloveless/.gem/ruby/2.1.0/gems/activesupport-4.2.0.rc2/lib/active_support/dependencies.rb:240:in `load_dependency' from /Users/sloveless/.gem/ruby/2.1.0/gems/activesupport-4.2.0.rc2/lib/active_support/dependencies.rb:268:in `load' from /Users/sloveless/.gem/ruby/2.1.0/gems/spring-commands-rspec-1.0.3/lib/spring/commands/rspec.rb:18:in `call' from /Users/sloveless/.rubies/ruby-2.1.0/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require' from /Users/sloveless/.rubies/ruby-2.1.0/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require' from -e:1:in `'
任何想法，为什么我可能会得到这个？ ……当然，我怎么能绕过它呢？
相关文件：
# app/application_controller.rb class ApplicationController 0.3.1' # Other utils gem 'uuidtools' # Serializing things gem 'active_model_serializers', '~> 0.8.2' # Persisting things gem 'pg', '~> 0.17.1' # gem 'activerecord-postgis-adapter', '~> 2.2.1' # gem 'redis' # Controller & routing things gem 'http_accept_language', '~> 2.0.2' gem 'kaminari' gem 'rack-cors', require: 'rack/cors' gem 'responders', '~> 2.0' group :development do gem 'brakeman', require: false gem 'guard-bundler' gem 'guard-rails' gem 'guard-rspec' gem 'guard-rubocop' gem 'rails_best_practices' gem 'rubocop', require: false gem 'quiet_assets' gem 'web-console', '~> 2.0' end group :development, :test do gem 'bullet' gem 'byebug' gem 'factory_girl_rails' gem 'faker' gem 'pry-rails' gem 'pry-rescue' gem 'pry-stack_explorer' gem 'rspec-rails' gem 'puma' gem 'spring' gem 'spring-commands-rspec' end group :test do gem 'json_spec' gem 'shoulda-matchers' end group :production do gem 'newrelic_rpm' end
编辑：毫不奇怪，这种情况发生在我手动发出请求时，而不仅仅是在测试期间。
以下使用rails-api / active_model_serializers 0.8.3为我工作：
去掉
include ActionController::MimeResponds include ActionController::ImplicitRender
加
include ActionController::RespondWith
在github上看到这个讨论 。
为清楚起见，如果控制器inheritance自ActionController::API并且包含ActionController::MimeResponds ，则看起来可以重现该问题。 为了避免控制器级的respond_to出错，我这样做了：
class ApplicationController < ActionController::API include ActionController::MimeResponds def self.respond_to(*mimes) include ActionController::RespondWith::ClassMethods end respond_to :json end
我没有看到如何解决respond_with的问题，但它会有点不同，因为它是一个实例方法。
看起来它是responders / rails-api不兼容。 我尝试了responders :location ApplicationController responders :location ，并且会得到一个带有undefined method 'responders' for ApplicationController:Class (NoMethodError)的回溯， undefined method 'responders' for ApplicationController:Class (NoMethodError) ，这让我相信responders gem将responders类方法添加到ActionController::Base 。 由于rails-api让你的控制器inheritance自ActionController::API ，因此responders方法实际上不会被添加到我的ApplicationController 。
确认： responders / lib / responders / controller_method.rb
我尝试使用Responders::ControllerMethod extend我的ApplicationController ，但这并没有让我解决问题。
我的解决方案实际上是使用rails-api ，然后是ApplicationController < ActionController::Base 。
如果您的控制器inheritance自ActionController::Metal您可能还需要include ActionController::RespondWith是您添加了responders gem。
我刚刚为我的gemfile添加了gem响应器做了一个bundle install然后我做了一个rails生成响应器：install并安装了这些文件。 之后我运行了我的rails生成脚手架食品名称：字符串卡路里：浮点数和db：drop db：create和db：migrate（删除并刷新数据库）我停止收到错误。
基本上当我在运行rails之前安装gems和文件时生成脚手架， 无论它开始工作。