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.
Pretty simple, eh?
Class Public methods
new(server, env, coder: ActiveSupport::JSON) Link
# File actioncable/lib/action_cable/connection/base.rb, line 55 def initialize(server, env, coder: ActiveSupport::JSON) @server, @env, @coder = server, env, coder @worker_pool = server.worker_pool @logger = new_tagged_logger @websocket = ActionCable::Connection::WebSocket.new(env, self, event_loop) @subscriptions = ActionCable::Connection::Subscriptions.new(self) @message_buffer = ActionCable::Connection::MessageBuffer.new(self) @_internal_subscriptions = nil @started_at = Time.now end
Instance Public methods
close(reason: nil, reconnect: true) Link
Close the WebSocket connection.
send_async(method, *arguments) Link
Invoke a method on the connection asynchronously through the pool of thread workers.
Return a basic hash of statistics for the connection keyed with
request_id. This can be returned by a health check against the connection.
Instance Private methods
The cookies of the request that initiated the WebSocket connection. Useful for performing authorization checks.
The request that initiated the WebSocket connection is available here. This gives access to the environment, cookies, etc.