Rails 5 - Cannot initialize ActionCable

Question

I just upgraded my app to Rails 5, I'm following a tutorial about ActionCable basics, but I cannot start a server.

Everytime I try to do so, I get the following error:

uninitialized constant ActionCable (NameError)

It seems like it comes from my routes.rb file, from this line :

mount ActionCable.server => '/cable'

This line is specified in every tutorial I've read so far, so I assume it is required for Actioncable to work. Has anyone encountered this problem before ? My gemfile is up-to-date, i'm using rails 5.0.0.1

Given that your Gemfile has Rails5, it should work - do you get the same error if you launch the server through bundler (e.g., `bundle exec rails s`)? — gmcnaughton, Oct 31 '16 at 14:10

score 1 · Answer 1 · answered Jan 27 '17 at 16:38

If you are sure that you are declaring the channel and connection files in the correct place, then make sure you are loading ActionCable in config/application.rb.

You may have something like the following in this file:

require "active_model/railtie"
require "active_job/railtie"
require "active_record/railtie"
require "action_controller/railtie"
require "action_mailer/railtie"
require "action_view/railtie"
# require "sprockets/railtie"
# require "rails/test_unit/railtie"

In which case you just need to add require "action_cable/engine".

Or, if you prefer you can use require "rails/all" to load all the frameworks as once. The Rails Initialization Process guide has more detail about this.

rails/all loads the following:

  active_record/railtie
  action_controller/railtie
  action_view/railtie
  action_mailer/railtie
  active_job/railtie
  action_cable/engine
  rails/test_unit/railtie
  sprockets/railtie

score 0 · Answer 2 · edited May 23 '17 at 11:53

0

As per this answer, make sure you have followed the following file path. You need app/channels/application_cable/channel.rb that look like this.

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

and app/channels/application_cable/connection.rb

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

edited May 23 '17 at 11:53

Community

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answered Oct 31 '16 at 13:33

Jayaprakash

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Nope, both files look just like this. – Pierre Olivier Tran Oct 31 '16 at 13:51

Rails 5 - Cannot initialize ActionCable

2 Answers2