---
title:
  "Rails 7.1 adds callbacks for Action Cable commands at the connection level"
description:
  "Rails 7.1 adds callbacks for Action Cable commands at the connection level"
canonical_url: "https://www.bigbinary.com/blog/rails-7-1-adds-callbacks-for-action-cable-connection"
markdown_url: "https://www.bigbinary.com/blog/rails-7-1-adds-callbacks-for-action-cable-connection.md"
---

# Rails 7.1 adds callbacks for Action Cable commands at the connection level

Rails 7.1 adds callbacks for Action Cable commands at the connection level

- Author: Ghouse Mohamed
- Published: August 2, 2022
- Categories: Rails, Rails 7

Action Cable allows us to add callbacks for individual channels. These are:
`after_subscribe`, `after_unsubscribe`, `before_subscribe`,
`before_unsubscribe`, `on_subscribe`, `on_unsubscribe`. These callbacks are
registered individually for each Channel. Before Rails 7.1, there was no way in
which we could register callbacks to be called before every command generically.
Rails 7.1 solves this problem by providing a set of callbacks that can be
registered at the connection level. And these callbacks are called for every
command, regardless of which channel's command is being invoked.

These are the following callbacks, which can be registered:

1. `before_command`: This callback is invoked before any command can be
   processed by the channel.
2. `around_command`: This callback is generally invoked around the command. Any
   piece of code before `yield` is run before the actual command and any piece
   of code after `yield` is run after the command has been processed by the
   channel.
3. `after_command`: This callback is invoked after the command has been
   processed by the channel.

Let's take a look at some example code to understand this behaviour better:

```ruby
class Connection < ActionCable::Connection::Base
  identified_by :current_user
  before_command :set_current_user
  around_command :register_telemetry_data
  after_command :update_current_user

  private

    def set_current_user
      if request.params["user_id"].present?
        self.current_user = User.find_by(request.params["user_id"])
      end
      reject_unauthorized_connection if self.current_user.nil?
    end

    def register_telemetry_data
      self.current_user.register_telemetry({ start: true })
      yield
      self.current_user.register_telemetry({ end: true })
    end

    def update_current_user
      self.current_user.touch(:updated_at)
    end
end
```

Here, we can expect `set_current_user` to be invoked before every command is
processed. Similar to this, we can also expect `update_current_user` to be
invoked after every command is processed. Whereas for the
`register_telemetry_data`,
`self.current_user.register_telemetry({ start: true })` is run before the
command is processed and then after the command is processed,
`self.current_user.register_telemetry({ end: true })` is run.

Please check out this [pull request](https://github.com/rails/rails/pull/44696)
for more details.

## Links

- [Human page](https://www.bigbinary.com/blog/rails-7-1-adds-callbacks-for-action-cable-connection)