ruby-on-rails-4 – 升级到Rails 4得到了IOError(没有打开读取)

我尝试将应用程序从3.2升级到rails 4.我认为所有的宝石冲突此刻已经解决,但后来我知道它可能会再次发生.

虽然我尝试“捆绑exec rails s”并在浏览器中打开应用程序转到app home索引,但它给了我这个错误：

IOError(未打开以供阅读)

有人可以帮忙吗？非常感谢.

这是我使用的宝石列表：

gem 'rails','4.0.1'

gem 'sass-rails','~> 4.0.0'
gem 'coffee-rails','~> 4.0.0'
gem 'uglifier','>= 1.3.0'

gem 'jquery-rails'

gem 'jbuilder','~> 1.2'
# add these gems to help with the transition:
gem 'protected_attributes'
gem 'rails-observers'
gem 'actionpack-page_caching'
gem 'actionpack-action_caching'
gem "activerecord-session_store"

这是控制台的日志消息：

Started GET "/" for 127.0.0.1 at 2013-11-06 20:16:27 +1100
Processing by HomeController#index as HTML
  PCategory Load (0.5ms)  SELECT "p_categories".* FROM "p_categories"
  Rendered home/index.html.erb within layouts/application (4.1ms)
Completed 500 Internal Server Error in 15ms

IOError (not opened for reading):
  activesupport (4.0.1) lib/active_support/json/encoding.rb:256:in `each'
  activesupport (4.0.1) lib/active_support/json/encoding.rb:256:in `to_a'
  activesupport (4.0.1) lib/active_support/json/encoding.rb:256:in `as_json'
  activesupport (4.0.1) lib/active_support/json/encoding.rb:58:in `block in as_json'
  activesupport (4.0.1) lib/active_support/json/encoding.rb:81:in 'check_for_circular_references'
  activesupport (4.0.1) lib/active_support/json/encoding.rb:57:in `as_json'
  activesupport (4.0.1) lib/active_support/json/encoding.rb:296:in `block in as_json'
  activesupport (4.0.1) lib/active_support/json/encoding.rb:296:in `each'
  activesupport (4.0.1) lib/active_support/json/encoding.rb:296:in `map'
  activesupport (4.0.1) lib/active_support/json/encoding.rb:296:in `as_json'
  activesupport (4.0.1) lib/active_support/json/encoding.rb:58:in `block in as_json'
  activesupport (4.0.1) lib/active_support/json/encoding.rb:81:in g`check_for_circular_references'
  activesupport (4.0.1) lib/active_support/json/encoding.rb:57:in `as_json'
  activesupport (4.0.1) lib/active_support/json/encoding.rb:296:in `block in as_json'
  activesupport (4.0.1) lib/active_support/json/encoding.rb:296:in `each'
  activesupport (4.0.1) lib/active_support/json/encoding.rb:296:in `map'
  activesupport (4.0.1) lib/active_support/json/encoding.rb:296:in `as_json'
  activesupport (4.0.1) lib/active_support/json/encoding.rb:50:in `block in encode'
  activesupport (4.0.1) lib/active_support/json/encoding.rb:81:in `check_for_circular_references'
  activesupport (4.0.1) lib/active_support/json/encoding.rb:49:in `encode'
  activesupport (4.0.1) lib/active_support/json/encoding.rb:306:in `block in encode_json'
  activesupport (4.0.1) lib/active_support/json/encoding.rb:306:in `each'
  activesupport (4.0.1) lib/active_support/json/encoding.rb:306:in `map'

解决方法

事实证明,创业板冲突是我遇到的类似问题的罪魁祸首.我用来自使用Rails的间接相关问题的代码修复了问题.请看下面,我希望这对你有帮助.

#fix for JSON gem/activesupport bug. More info: https://stackoverflow.com/questions/683989/how-do-you-deal-with-the-conflict-between-activesupportjson-and-the-json-gem
if defined?(ActiveSupport::JSON)
  [Object,Array,FalseClass,Float,Hash,Integer,NilClass,String,TrueClass].each do |klass|
    klass.class_eval do
      def to_json(*args)
        super(args)
      end
      def as_json(*args)
        super(args)
      end
    end
  end
end