uninitialized constant> ActionCable :: Server :: Configuration :: ApplicationCable

该错误与项目中没有正确的ActionCable文件有关.你需要app/channels/application_cable/channel.rb看起来像这样

module ApplicationCable
  class Channel < ActionCable::Channel::Base
  end
end

和 app/channels/application_cable/connection.rb

module ApplicationCable
  class Connection < ActionCable::Connection::Base
  end
end

尝试在Rails 4.2.5中使用ActionCable时遇到了同样的问题,解决方案是将以下内容添加到config/application.rb:

config.autoload_paths += %W(#{config.root}/app/channels)

这是使用ActionCable gem:

gem 'actioncable', github: 'rails/actioncable', branch: 'archive'

如果您从以前的版本升级(当actioncable不在捆绑包中时),请检查是否config/application.rb包含

require "action_cable/engine"