How to fix "Could not execute command from ({"command"=>"subscribe", "identifier"=>"{\"channel\":\"ConversationChannel\"}"}) "

Question

I'm trying to get user to connect user to conversation_channel and I receive:

Could not execute command from ({"command"=>"subscribe", "identifier"=>"  {\"channel\":\"ConversationChannel\"}"}) [NoMethodError - undefined method `id' for nil:NilClass]: /mnt/c/rails_apps/Picnotes/app/channels/conversation_channel.rb:6:in `subscribed' |

I tried hardcoding current_user.id to 1 or 2 and I got:

Started GET "/cable" for 127.0.0.1 at 2019-01-22 22:06:36 -0800
Started GET "/cable/" [WebSocket] for 127.0.0.1 at 2019-01-22 22:06:36 -0800
Successfully upgraded to WebSocket (REQUEST_METHOD: GET, HTTP_CONNECTION: Upgrade, HTTP_UPGRADE: websocket)
ConversationChannel is transmitting the subscription confirmation
ConversationChannel is streaming from conversations-1

My code is below:

# Be sure to restart your server when you modify this file. Action Cable runs in a loop that does not support auto reloading.
class ConversationChannel < ApplicationCable::Channel
  # Create a unique channel for each user.
...
  def subscribed
    stream_from "conversations-#{current_user.id}"
  end

  # Removes all connected connections.
  def unsubscribed
    stop_all_streams
  end
...

  end
end    

module ApplicationCable
  class Connection < ActionCable::Connection::Base
    identified_by :current_user

    def connect
      self.current_user = current_user
    end
  end
end

class ApplicationController < ActionController::Base
  protect_from_forgery with: :exception
  before_action :initiate_instance_variables

 ...

  def current_user
    @current_user ||= User.find_by(id: session[:user_id])
  end

  helper_method :current_user

  ...

end

I expect #{current_user.id} to be the user id (constant: 1 or 2), but the object is always nil.

The title is missleading... There seems to no issue with ActionCable. You actual issue is that you don`t have a current_user available. What is `session[:user_id]` set to? — Denny Mueller, Jan 23 '19 at 12:29

score 0 · Answer 1 · answered Jan 24 '19 at 23:05

According the rails guides for ActionCable you need to get your user id from your cookies

# app/channels/application_cable/connection.rb
module ApplicationCable
  class Connection < ActionCable::Connection::Base
    identified_by :current_user

    def connect
      self.current_user = find_verified_user
    end

    private
      def find_verified_user
        if verified_user = User.find_by(id: cookies.encrypted[:user_id])
          verified_user
        else
          reject_unauthorized_connection
        end
      end
  end
end

How to fix "Could not execute command from ({"command"=>"subscribe", "identifier"=>"{\"channel\":\"ConversationChannel\"}"}) "

1 Answers1