升级至Rails 7.0.4后出现undefined method `unloadable'错误求助

问题场景 #

现有继承自WebsocketRails::BaseController的控制器代码：

class SocketController < WebsocketRails::BaseController
  before_action :authenticate_user!
end

将Rails版本升级至7.0.4后，执行rails s启动服务时触发如下错误：

Failure/Error:
  class SocketController < WebsocketRails::BaseController
    before_action :authenticate_user!

NoMethodError:
  undefined method `unloadable' for WebsocketRails::BaseController:Class

          unloadable controller
          ^^^^^^^^^^
# ./vendor/bundle/ruby/3.1.0/gems/websocket-rails-0.7.0/lib/websocket_rails/base_controller.rb:45:in `inherited'
# ./app/controllers/socket_controller.rb:1:in `<top (required)>'
# ./vendor/bundle/ruby/3.1.0/gems/zeitwerk-2.6.6/lib/zeitwerk/kernel.rb:30:in `require'
# ./vendor/bundle/ruby/3.1.0/gems/zeitwerk-2.6.6/lib/zeitwerk/kernel.rb:30:in `require'
# ./vendor/bundle/ruby/3.1.0/gems/zeitwerk-2.6.6/lib/zeitwerk/loader/helpers.rb:135:in `const_get'
# ./vendor/bundle/ruby/3.1.0/gems/zeitwerk-2.6.6/lib/zeitwerk/loader/helpers.rb:135:in `cget'
# ./vendor/bundle/ruby/3.1.0/gems/zeitwerk-2.6.6/lib/zeitwerk/loader/eager_load.rb:169:in `block in actual_eager_load_dir'
# ./vendor/bundle/ruby/3.1.0/gems/zeitwerk-2.6.6/lib/zeitwerk/loader/helpers.rb:40:in `block in ls'
# ./vendor/bundle/ruby/3.1.0/gems/zeitwerk-2.6.6/lib/zeitwerk/loader/helpers.rb:25:in `each'
# ./vendor/bundle/ruby/3.1.0/gems/zeitwerk-2.6.6/lib/zeitwerk/loader/helpers.rb:25:in `ls'
# ./vendor/bundle/ruby/3.1.0/gems/zeitwerk-2.6.6/lib/zeitwerk/loader/eager_load.rb:164:in `actual_eager_load_dir'
# ./vendor/bundle/ruby/3.1.0/gems/zeitwerk-2.6.6/lib/zeitwerk/loader/eager_load.rb:17:in `block (2 levels) in eager_load'
# ./vendor/bundle/ruby/3.1.0/gems/zeitwerk-2.6.6/lib/zeitwerk/loader/eager_load.rb:16:in `each'
# ./vendor/bundle/ruby/3.1.0/gems/zeitwerk-2.6.6/lib/zeitwerk/loader/eager_load.rb:16:in `block in eager_load'
# ./vendor/bundle/ruby/3.1.0/gems/zeitwerk-2.6.6/lib/zeitwerk/loader/eager_load.rb:10:in `synchronize'
# ./vendor/bundle/ruby/3.1.0/gems/zeitwerk-2.6.6/lib/zeitwerk/loader/eager_load.rb:10:in `eager_load'
# ./vendor/bundle/ruby/3.1.0/gems/zeitwerk-2.6.6/lib/zeitwerk/loader.rb:296:in `block in eager_load_all'
# ./vendor/bundle/ruby/3.1.0/gems/zeitwerk-2.6.6/lib/zeitwerk/loader.rb:294:in `each'
# ./vendor/bundle/ruby/3.1.0/gems/zeitwerk-2.6.6/lib/zeitwerk/loader.rb:294:in `eager_load_all'
# ./vendor/bundle/ruby/3.1.0/gems/railties-7.0.4/lib/rails/application/finisher.rb:74:in `block in <module:Finisher>'
# ./vendor/bundle/ruby/3.1.0/gems/railties-7.0.4/lib/rails/initializable.rb:32:in `instance_exec'
# ./vendor/bundle/ruby/3.1.0/gems/railties-7.0.4/lib/rails/initializable.rb:32:in `run'
# ./vendor/bundle/ruby/3.1.0/gems/railties-7.0.4/lib/rails/initializable.rb:61:in `block in run_initializers'
# ./vendor/bundle/ruby/3.1.0/gems/railties-7.0.4/lib/rails/initializable.rb:60:in `run_initializers'
# ./vendor/bundle/ruby/3.1.0/gems/railties-7.0.4/lib/rails/application.rb:372:in `initialize!'
# ./config/environment.rb:5:in `<top (required)>'

问题原因 #

websocket-rails 0.7.0版本的代码中，WebsocketRails::BaseController的inherited方法调用了Rails旧版本的unloadable方法，但Rails 7.0+默认使用Zeitwerk作为代码加载器，已经移除了unloadable这个方法，导致调用时报错。

修复方案 #

方案1：给websocket-rails打补丁 #

在项目的config/initializers目录下新建websocket_rails_patch.rb文件，添加以下代码，手动实现unloadable方法：

module WebsocketRails
  class BaseController
    def self.unloadable(_controller = nil)
      # 空实现，适配Rails7的Zeitwerk加载机制
    end
  end
end

保存后重启服务即可解决报错。

方案2：迁移到官方ActionCable #

websocket-rails已经多年未更新，后续可能会出现更多兼容性问题。Rails 7默认集成的ActionCable是官方维护的WebSocket解决方案，稳定性和兼容性更好。迁移步骤大致如下：

• 移除Gemfile中的websocket-rails（Rails7默认已包含ActionCable，无需手动添加）
• 将原SocketController的逻辑迁移到ActionCable的Channel中
• 调整前端WebSocket连接代码，适配ActionCable的连接方式

方案3：临时降级Rails版本 #

如果暂时无法迁移或打补丁，可以将Rails版本降级到websocket-rails支持的版本（比如Rails 6.x），修改Gemfile中的Rails版本后执行bundle install，但这只是临时方案，不推荐长期使用。

内容的提问来源于stack exchange，提问作者suffurt