关于 ruby?? on rails:NoMethodError – nil:NilClass 的未定义方法”safe_constantize”


NoMethodError - undefined method `safe_constantize' for nil:NilClass

我正在尝试按照 GoRails.com 上的 actioncable 指南创建一个 ActionCable 聊天室。

当我尝试连接到 ActionCable 时，我收到以下错误：
NoMethodError - nil:NilClass

的未定义方法"safe_constantize"

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[ActionCable] [User 1] Could not execute command from
{"command"=>"subscribe","identifier"=>"
{"ChatroomsChannel":"ChatroomsChannel","room_id":1}"})
[NoMethodError - undefined method `safe_constantize' for
nil:NilClass]: /Users/Mathias/.rvm/gems/ruby-
2.2.3@chatroomv1/gems/actioncable-
5.0.0.rc2/lib/action_cable/connection/subscriptions.rb:29:in `add' |
/Users/Mathias/.rvm/gems/ruby-2.2.3@chatroomv1/gems/actioncable-
5.0.0.rc2/lib/action_cable/connection/subscriptions.rb:15:in
`execute_command' | /Users/Mathias/.rvm/gems/ruby-
2.2.3@chatroomv1/gems/actioncable-
5.0.0.rc2/lib/action_cable/connection/base.rb:88:in
`dispatch_websocket_message' | /Users/Mathias/.rvm/gems/ruby-
2.2.3@chatroomv1/gems/actioncable-
5.0.0.rc2/lib/action_cable/server/worker.rb:54:in `block in invoke' |
/Users/Mathias/.rvm/gems/ruby-2.2.3@chatroomv1/gems/actioncable-
5.0.0.rc2/lib/action_cable/server/worker.rb:39:in `block in work'

我的 app/channels/chatrooms_channel.rb 看起来像这样：

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def subscribed
   @chatroom = Chatroom.find(params[:room_id])
   #puts params[:room_id]
   #current_user.join_room(@chatroom)
   stream_from"chatrooms:#{@chatroom.id}"
   # stream_from"some_channel"
end

也许值得一提的是我从 rails 4 升级到 rails 5.0.0.rc2。

谢谢你，

相关讨论

在 assets/javascripts/channels/chatroom.coffee

如果你需要分配params，频道名称也必须在params hash中：

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App['chatroom' + roomId] = App.cable.subscriptions.create {
  channel: 'ChatroomChannel',
  room_id: roomId
}, {
  received: ->
    ...
}

而且只有在不需要params的情况下，才可以写出不带hash的频道名：

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App.chatroom = App.cable.subscriptions.create 'ChatroomChannel',
  received: ->
    ...