Skip to Content Skip to Search

Action Cable Connection Base ↑

For every WebSocket connection the Action Cable server accepts, a Connection object will be instantiated. This instance becomes the parent of all of the channel subscriptions that are created from there on. Incoming messages are then routed to these channel subscriptions based on an identifier sent by the Action Cable consumer. The Connection itself does not deal with any specific application logic beyond authentication and authorization.

Here’s a basic example:

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

    def connect
      self.current_user = find_verified_user
      logger.add_tags current_user.name
    end

    def disconnect
      # Any cleanup work needed when the cable connection is cut.
    end

    private
      def find_verified_user
        User.find_by_identity(cookies.encrypted[:identity_id]) ||
          reject_unauthorized_connection
      end
  end
end

First, we declare that this connection can be identified by its current_user. This allows us to later be able to find all connections established for that current_user (and potentially disconnect them). You can declare as many identification indexes as you like. Declaring an identification means that an attr_accessor is automatically set for that key.

Second, we rely on the fact that the WebSocket connection is established with the cookies from the domain being sent along. This makes it easy to use signed cookies that were set when logging in via a web interface to authorize the WebSocket connection.

Finally, we add a tag to the connection-specific logger with the name of the current user to easily distinguish their messages in the log.

Methods
B
C
D
H
N
S
Included Modules

Attributes

[R] logger
[R] subscriptions

Class Public methods

new(server, socket)

Source: show | on GitHub 

# File actioncable/lib/action_cable/connection/base.rb, line 68
def initialize(server, socket)
  @server = server
  @socket = socket

  @logger = socket.logger
  @subscriptions  = Subscriptions.new(self)

  @_internal_subscriptions = nil

  @started_at = Time.now
end

Instance Public methods

beat()

Source: show | on GitHub 

# File actioncable/lib/action_cable/connection/base.rb, line 142
def beat
  transmit type: ActionCable::INTERNAL[:message_types][:ping], message: Time.now.to_i
end

close(reason: nil, reconnect: true)

Close the connection.

Source: show | on GitHub 

# File actioncable/lib/action_cable/connection/base.rb, line 121
def close(reason: nil, reconnect: true)
  transmit(
    type: ActionCable::INTERNAL[:message_types][:disconnect],
    reason: reason,
    reconnect: reconnect
  ) rescue nil
  socket.close
end

connect()

This method is called every time an Action Cable client establishes an underlying connection. Override it in your class to define authentication logic and populate connection identifiers.

Source: show | on GitHub 

# File actioncable/lib/action_cable/connection/base.rb, line 83
def connect
end

disconnect()

This method is called every time an Action Cable client disconnects. Override it in your class to cleanup the relevant application state (e.g., presence, online counts, etc.)

Source: show | on GitHub 

# File actioncable/lib/action_cable/connection/base.rb, line 88
def disconnect
end

handle_channel_command(payload)

Also aliased as: handle_incoming

Source: show | on GitHub 

# File actioncable/lib/action_cable/connection/base.rb, line 106
def handle_channel_command(payload)
  run_callbacks :command do
    subscriptions.execute_command payload
  end
rescue Exception => e
  rescue_with_handler(e) || raise
end

handle_close()

Source: show | on GitHub 

# File actioncable/lib/action_cable/connection/base.rb, line 99
def handle_close
  subscriptions.unsubscribe_from_all
  unsubscribe_from_internal_channel

  disconnect
end

handle_incoming(payload)

Alias for: handle_channel_command

handle_open()

Source: show | on GitHub 

# File actioncable/lib/action_cable/connection/base.rb, line 91
def handle_open
  connect
  subscribe_to_internal_channel
  send_welcome_message
rescue ActionCable::Connection::Authorization::UnauthorizedError
  close(reason: ActionCable::INTERNAL[:disconnect_reasons][:unauthorized], reconnect: false)
end

statistics()

Return a basic hash of statistics for the connection keyed with identifier, started_at, subscriptions, and request_id. This can be returned by a health check against the connection.

Source: show | on GitHub 

# File actioncable/lib/action_cable/connection/base.rb, line 133
def statistics
  {
    identifier: connection_identifier,
    started_at: @started_at,
    subscriptions: subscriptions.identifiers,
    request_id: env["action_dispatch.request_id"]
  }
end

Instance Private methods

cookies()

The cookies of the request that initiated the WebSocket connection. Useful for performing authorization checks.

Source: show | on GitHub 

# File actioncable/lib/action_cable/connection/base.rb, line 156
def cookies # :doc:
  request.cookie_jar
end