diff options
Diffstat (limited to 'actioncable/lib/action_cable/connection/base.rb')
| -rw-r--r-- | actioncable/lib/action_cable/connection/base.rb | 255 |
1 files changed, 255 insertions, 0 deletions
diff --git a/actioncable/lib/action_cable/connection/base.rb b/actioncable/lib/action_cable/connection/base.rb new file mode 100644 index 0000000000..cc4e0f8c8b --- /dev/null +++ b/actioncable/lib/action_cable/connection/base.rb @@ -0,0 +1,255 @@ +require 'action_dispatch' + +module ActionCable + module Connection + # For every WebSocket 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 + # + # protected + # def find_verified_user + # if current_user = User.find_by_identity cookies.signed[:identity_id] + # current_user + # else + # reject_unauthorized_connection + # end + # 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 Base + include Identification + include InternalChannel + include Authorization + + attr_reader :server, :env, :subscriptions, :logger, :worker_pool, :protocol + delegate :event_loop, :pubsub, to: :server + + 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, server.config.client_socket_class) + @subscriptions = ActionCable::Connection::Subscriptions.new(self) + @message_buffer = ActionCable::Connection::MessageBuffer.new(self) + + @_internal_subscriptions = nil + @started_at = Time.now + end + + # Called by the server when a new WebSocket connection is established. This configures the callbacks intended for overwriting by the user. + # This method should not be called directly -- instead rely upon on the #connect (and #disconnect) callbacks. + def process #:nodoc: + logger.info started_request_message + + if websocket.possible? && allow_request_origin? + respond_to_successful_request + else + respond_to_invalid_request + end + end + + # Decodes WebSocket messages and dispatches them to subscribed channels. + # WebSocket message transfer encoding is always JSON. + def receive(websocket_message) #:nodoc: + send_async :dispatch_websocket_message, websocket_message + end + + def dispatch_websocket_message(websocket_message) #:nodoc: + if websocket.alive? + subscriptions.execute_command decode(websocket_message) + else + logger.error "Ignoring message processed after the WebSocket was closed: #{websocket_message.inspect})" + end + end + + def transmit(cable_message) # :nodoc: + websocket.transmit encode(cable_message) + end + + # Close the WebSocket connection. + def close + websocket.close + end + + # Invoke a method on the connection asynchronously through the pool of thread workers. + def send_async(method, *arguments) + worker_pool.async_invoke(self, method, *arguments) + end + + # Return a basic hash of statistics for the connection keyed with `identifier`, `started_at`, and `subscriptions`. + # This can be returned by a health check against the connection. + def statistics + { + identifier: connection_identifier, + started_at: @started_at, + subscriptions: subscriptions.identifiers, + request_id: @env['action_dispatch.request_id'] + } + end + + def beat + transmit type: ActionCable::INTERNAL[:message_types][:ping], message: Time.now.to_i + end + + def on_open # :nodoc: + send_async :handle_open + end + + def on_message(message) # :nodoc: + message_buffer.append message + end + + def on_error(message) # :nodoc: + # ignore + end + + def on_close(reason, code) # :nodoc: + send_async :handle_close + end + + protected + # The request that initiated the WebSocket connection is available here. This gives access to the environment, cookies, etc. + def request + @request ||= begin + environment = Rails.application.env_config.merge(env) if defined?(Rails.application) && Rails.application + ActionDispatch::Request.new(environment || env) + end + end + + # The cookies of the request that initiated the WebSocket connection. Useful for performing authorization checks. + def cookies + request.cookie_jar + end + + attr_reader :websocket + attr_reader :message_buffer + + private + def encode(cable_message) + @coder.encode cable_message + end + + def decode(websocket_message) + @coder.decode websocket_message + end + + def handle_open + @protocol = websocket.protocol + connect if respond_to?(:connect) + subscribe_to_internal_channel + send_welcome_message + + message_buffer.process! + server.add_connection(self) + rescue ActionCable::Connection::Authorization::UnauthorizedError + respond_to_invalid_request + end + + def handle_close + logger.info finished_request_message + + server.remove_connection(self) + + subscriptions.unsubscribe_from_all + unsubscribe_from_internal_channel + + disconnect if respond_to?(:disconnect) + end + + def send_welcome_message + # Send welcome message to the internal connection monitor channel. + # This ensures the connection monitor state is reset after a successful + # websocket connection. + transmit type: ActionCable::INTERNAL[:message_types][:welcome] + end + + def allow_request_origin? + return true if server.config.disable_request_forgery_protection + + if Array(server.config.allowed_request_origins).any? { |allowed_origin| allowed_origin === env['HTTP_ORIGIN'] } + true + else + logger.error("Request origin not allowed: #{env['HTTP_ORIGIN']}") + false + end + end + + def respond_to_successful_request + logger.info successful_request_message + websocket.rack_response + end + + def respond_to_invalid_request + close if websocket.alive? + + logger.error invalid_request_message + logger.info finished_request_message + [ 404, { 'Content-Type' => 'text/plain' }, [ 'Page not found' ] ] + end + + # Tags are declared in the server but computed in the connection. This allows us per-connection tailored tags. + def new_tagged_logger + TaggedLoggerProxy.new server.logger, + tags: server.config.log_tags.map { |tag| tag.respond_to?(:call) ? tag.call(request) : tag.to_s.camelize } + end + + def started_request_message + 'Started %s "%s"%s for %s at %s' % [ + request.request_method, + request.filtered_path, + websocket.possible? ? ' [WebSocket]' : '[non-WebSocket]', + request.ip, + Time.now.to_s ] + end + + def finished_request_message + 'Finished "%s"%s for %s at %s' % [ + request.filtered_path, + websocket.possible? ? ' [WebSocket]' : '[non-WebSocket]', + request.ip, + Time.now.to_s ] + end + + def invalid_request_message + 'Failed to upgrade to WebSocket (REQUEST_METHOD: %s, HTTP_CONNECTION: %s, HTTP_UPGRADE: %s)' % [ + env["REQUEST_METHOD"], env["HTTP_CONNECTION"], env["HTTP_UPGRADE"] + ] + end + + def successful_request_message + 'Successfully upgraded to WebSocket (REQUEST_METHOD: %s, HTTP_CONNECTION: %s, HTTP_UPGRADE: %s)' % [ + env["REQUEST_METHOD"], env["HTTP_CONNECTION"], env["HTTP_UPGRADE"] + ] + end + end + end +end |