class Ably::Realtime::Channel::ChannelManager

ChannelManager is responsible for all actions relating to channel state: attaching, detaching or failure Channel state changes are performed by this class and executed from {ChannelStateMachine}

This is a private class and should never be used directly by developers as the API is likely to change in future.

@api private

Attributes

pending_state_change_timer[R]

Public Class Methods

new(channel, connection) click to toggle source
# File lib/submodules/ably-ruby/lib/ably/realtime/channel/channel_manager.rb, line 12
def initialize(channel, connection)
  @channel    = channel
  @connection = connection
end

Public Instance Methods

attach() click to toggle source

Commence attachment

# File lib/submodules/ably-ruby/lib/ably/realtime/channel/channel_manager.rb, line 18
def attach
  if can_transition_to?(:attached)
    connect_if_connection_initialized
    send_attach_protocol_message
  end
end
attached(attached_protocol_message) click to toggle source

Channel is attached, notify presence if sync is expected

# File lib/submodules/ably-ruby/lib/ably/realtime/channel/channel_manager.rb, line 35
def attached(attached_protocol_message)
  # If no attached ProtocolMessage then this attached request was triggered by the client
  # library, such as returning to attached whne detach has failed
  if attached_protocol_message
    update_presence_sync_state_following_attached attached_protocol_message
    channel.properties.set_attach_serial(attached_protocol_message.channel_serial)
    channel.options.set_modes_from_flags(attached_protocol_message.flags)
    channel.options.set_params(attached_protocol_message.params)
  end
end
detach(error, previous_state) click to toggle source

Commence attachment

# File lib/submodules/ably-ruby/lib/ably/realtime/channel/channel_manager.rb, line 26
def detach(error, previous_state)
  if connection.closed? || connection.connecting? || connection.suspended?
    channel.transition_state_machine :detached, reason: error
  elsif can_transition_to?(:detached)
    send_detach_protocol_message previous_state
  end
end
detached_received(reason) click to toggle source

Handle DETACED messages, see RTL13 for server-initated detaches

# File lib/submodules/ably-ruby/lib/ably/realtime/channel/channel_manager.rb, line 86
def detached_received(reason)
  case channel.state.to_sym
  when :detaching
    channel.transition_state_machine :detached, reason: reason
  when :attached, :suspended
    channel.transition_state_machine :attaching, reason: reason
  else
    logger.debug { "ChannelManager: DETACHED ProtocolMessage received, but no action to take as not DETACHING, ATTACHED OR SUSPENDED" }
  end
end
drop_pending_queue_from_ack(ack_protocol_message) { |protocol_message| ... } click to toggle source
# File lib/submodules/ably-ruby/lib/ably/realtime/channel/channel_manager.rb, line 149
def drop_pending_queue_from_ack(ack_protocol_message)
  message_serial_up_to = ack_protocol_message.message_serial + ack_protocol_message.count - 1
  connection.__pending_message_ack_queue__.drop_while do |protocol_message|
    if protocol_message.message_serial <= message_serial_up_to
      yield protocol_message
      true
    end
  end
end
duplicate_attached_received(protocol_message) click to toggle source
# File lib/submodules/ably-ruby/lib/ably/realtime/channel/channel_manager.rb, line 62
def duplicate_attached_received(protocol_message)
  if protocol_message.error
    channel.set_channel_error_reason protocol_message.error
    log_channel_error protocol_message.error
  end

  channel.properties.set_attach_serial(protocol_message.channel_serial)
  channel.options.set_modes_from_flags(protocol_message.flags)

  if protocol_message.has_channel_resumed_flag?
    logger.debug { "ChannelManager: Additional resumed ATTACHED message received for #{channel.state} channel '#{channel.name}'" }
  else
    channel.emit :update, Ably::Models::ChannelStateChange.new(
      current: channel.state,
      previous: channel.state,
      event: Ably::Realtime::Channel::EVENT(:update),
      reason: protocol_message.error,
      resumed: false,
    )
    update_presence_sync_state_following_attached protocol_message
  end
end
fail_messages_awaiting_ack(error, options = {}) click to toggle source

When continuity on the connection is interrupted or channel becomes suspended (implying loss of continuity) then all messages published but awaiting an ACK from Ably should be failed with a NACK @param [Hash] options @option options [Boolean] :immediately

# File lib/submodules/ably-ruby/lib/ably/realtime/channel/channel_manager.rb, line 101
def fail_messages_awaiting_ack(error, options = {})
  immediately = options[:immediately] || false

  fail_proc = lambda do
    error = Ably::Exceptions::MessageDeliveryFailed.new("Continuity of connection was lost so published messages awaiting ACK have failed") unless error
    fail_messages_in_queue connection.__pending_message_ack_queue__, error
  end

  # Allow a short time for other queued operations to complete before failing all messages
  if immediately
    fail_proc.call
  else
    EventMachine.add_timer(0.1) { fail_proc.call }
  end
end
fail_messages_in_queue(queue, error) click to toggle source
# File lib/submodules/ably-ruby/lib/ably/realtime/channel/channel_manager.rb, line 125
def fail_messages_in_queue(queue, error)
  queue.delete_if do |protocol_message|
    if protocol_message.action.match_any?(:presence, :message)
      if protocol_message.channel == channel.name
        nack_messages protocol_message, error
        true
      end
    end
  end
end
fail_queued_messages(error) click to toggle source

When a channel becomes suspended or failed, all queued messages should be failed immediately as we don’t queue in any of those states

# File lib/submodules/ably-ruby/lib/ably/realtime/channel/channel_manager.rb, line 120
def fail_queued_messages(error)
  error = Ably::Exceptions::MessageDeliveryFailed.new("Queued messages on channel '#{channel.name}' in state '#{channel.state}' will never be delivered") unless error
  fail_messages_in_queue connection.__outgoing_message_queue__, error
end
log_channel_error(error) click to toggle source

An error has occurred on the channel

# File lib/submodules/ably-ruby/lib/ably/realtime/channel/channel_manager.rb, line 47
def log_channel_error(error)
  logger.error { "ChannelManager: Channel '#{channel.name}' error: #{error}" }
end
nack_message(message, error, protocol_message = nil) click to toggle source
# File lib/submodules/ably-ruby/lib/ably/realtime/channel/channel_manager.rb, line 144
def nack_message(message, error, protocol_message = nil)
  logger.debug { "Calling NACK failure callbacks for #{message.class.name} - #{message.to_json} #{"protocol message: #{protocol_message}" if protocol_message}" }
  message.fail error
end
nack_messages(protocol_message, error) click to toggle source
# File lib/submodules/ably-ruby/lib/ably/realtime/channel/channel_manager.rb, line 136
def nack_messages(protocol_message, error)
  (protocol_message.messages + protocol_message.presence).each do |message|
    nack_message message, error, protocol_message
  end
  logger.debug { "Calling NACK failure callbacks for #{protocol_message.class.name} - #{protocol_message.to_json}" }
  protocol_message.fail error
end
request_reattach(options = {}) click to toggle source

Request channel to be reattached by sending an attach protocol message @param [Hash] options @option options [Ably::Models::ErrorInfo] :reason

# File lib/submodules/ably-ruby/lib/ably/realtime/channel/channel_manager.rb, line 54
def request_reattach(options = {})
  reason = options[:reason]
  send_attach_protocol_message
  logger.debug { "Explicit channel reattach request sent to Ably due to #{reason}" }
  channel.set_channel_error_reason(reason) if reason
  channel.transition_state_machine! :attaching, reason: reason unless channel.attaching?
end
start_attach_from_suspended_timer() click to toggle source

If the connection is still connected and the channel still suspended after channel_retry_timeout has passed, then attempt to reattach automatically, see RTL13b

# File lib/submodules/ably-ruby/lib/ably/realtime/channel/channel_manager.rb, line 161
def start_attach_from_suspended_timer
  cancel_attach_from_suspended_timer
  if connection.connected?
    channel.unsafe_once { |event| cancel_attach_from_suspended_timer unless event == :update }
    connection.unsafe_once { |event| cancel_attach_from_suspended_timer unless event == :update }

    @attach_from_suspended_timer = EventMachine::Timer.new(channel_retry_timeout) do
      channel.transition_state_machine! :attaching
    end
  end
end

Private Instance Methods

cancel_attach_from_suspended_timer() click to toggle source
# File lib/submodules/ably-ruby/lib/ably/realtime/channel/channel_manager.rb, line 186
def cancel_attach_from_suspended_timer
  @attach_from_suspended_timer.cancel if @attach_from_suspended_timer
  @attach_from_suspended_timer = nil
end
channel() click to toggle source
# File lib/submodules/ably-ruby/lib/ably/realtime/channel/channel_manager.rb, line 176
def channel
  @channel
end
channel_retry_timeout() click to toggle source
# File lib/submodules/ably-ruby/lib/ably/realtime/channel/channel_manager.rb, line 200
def channel_retry_timeout
  connection.defaults.fetch(:channel_retry_timeout)
end
connect_if_connection_initialized() click to toggle source

If the connection has not previously connected, connect now

# File lib/submodules/ably-ruby/lib/ably/realtime/channel/channel_manager.rb, line 192
def connect_if_connection_initialized
  connection.connect if connection.initialized?
end
connection() click to toggle source
# File lib/submodules/ably-ruby/lib/ably/realtime/channel/channel_manager.rb, line 180
def connection
  @connection
end
logger() click to toggle source
# File lib/submodules/ably-ruby/lib/ably/realtime/channel/channel_manager.rb, line 264
def logger
  connection.logger
end
realtime_request_timeout() click to toggle source
# File lib/submodules/ably-ruby/lib/ably/realtime/channel/channel_manager.rb, line 196
def realtime_request_timeout
  connection.defaults.fetch(:realtime_request_timeout)
end
send_attach_protocol_message() click to toggle source
# File lib/submodules/ably-ruby/lib/ably/realtime/channel/channel_manager.rb, line 204
def send_attach_protocol_message
  message_options = {}
  message_options[:params] = channel.options.params if channel.options.params.any?
  message_options[:flags] = channel.options.modes_to_flags if channel.options.modes
  if channel.attach_resume
    message_options[:flags] = message_options[:flags].to_i | Ably::Models::ProtocolMessage::ATTACH_FLAGS_MAPPING[:resume]
  end

  send_state_change_protocol_message Ably::Models::ProtocolMessage::ACTION.Attach, :suspended, message_options
end
send_detach_protocol_message(previous_state) click to toggle source
# File lib/submodules/ably-ruby/lib/ably/realtime/channel/channel_manager.rb, line 215
def send_detach_protocol_message(previous_state)
  send_state_change_protocol_message Ably::Models::ProtocolMessage::ACTION.Detach, previous_state # return to previous state if failed
end
send_state_change_protocol_message(new_state, state_if_failed, message_options = {}) click to toggle source
# File lib/submodules/ably-ruby/lib/ably/realtime/channel/channel_manager.rb, line 219
def send_state_change_protocol_message(new_state, state_if_failed, message_options = {})
  state_at_time_of_request = channel.state
  @pending_state_change_timer = EventMachine::Timer.new(realtime_request_timeout) do
    if channel.state == state_at_time_of_request
      error = Ably::Models::ErrorInfo.new(code: Ably::Exceptions::Codes::CHANNEL_OPERATION_FAILED_NO_RESPONSE_FROM_SERVER, message: "Channel #{new_state} operation failed (timed out)")
      channel.transition_state_machine state_if_failed, reason: error
    end
  end

  channel.once_state_changed do
    @pending_state_change_timer.cancel if @pending_state_change_timer
    @pending_state_change_timer = nil
  end

  resend_if_disconnected_and_connected = lambda do
    connection.unsafe_once(:disconnected) do
      next unless pending_state_change_timer
      connection.unsafe_once(:connected) do
        next unless pending_state_change_timer
        connection.send_protocol_message(
          action:  new_state.to_i,
          channel: channel.name,
          **message_options.to_h
        )
        resend_if_disconnected_and_connected.call
      end
    end
  end
  resend_if_disconnected_and_connected.call

  connection.send_protocol_message(
    action:  new_state.to_i,
    channel: channel.name,
    **message_options.to_h
  )
end
update_presence_sync_state_following_attached(attached_protocol_message) click to toggle source
# File lib/submodules/ably-ruby/lib/ably/realtime/channel/channel_manager.rb, line 256
def update_presence_sync_state_following_attached(attached_protocol_message)
  if attached_protocol_message.has_presence_flag?
    channel.presence.manager.sync_expected
  else
    channel.presence.manager.sync_not_expected
  end
end