• $nchan_channel_id
  The channel id extracted from a publisher or subscriber location request. For multiplexed locations, this is the first channel id in the list.

• $nchan_channel_id1, $nchan_channel_id2, $nchan_channel_id3, $nchan_channel_id4
  As above, but for the nth channel id in multiplexed channels.

• $nchan_subscriber_type
  For subscriber locations, this variable is set to the subscriber type (websocket, longpoll, etc.).

• $nchan_publisher_type
  For publisher locations, this variable is set to the subscriber type (http or websocket).

• $nchan_prev_message_id, $nchan_message_id The current and previous (if applicable) message id for publisher request or subscriber response.

• $nchan_channel_event For channel events, this is the event name. Useful when configuring nchan_channel_event_string.

• $nchan_version Current Nchan version. Available since 1.1.5.

Additionally, nchan_stub_status data is also exposed as variables. These are available only when nchan_stub_status is enabled on at least one location:

• $nchan_stub_status_total_published_messages
• $nchan_stub_status_stored_messages
• $nchan_stub_status_shared_memory_used
• $nchan_stub_status_channels
• $nchan_stub_status_subscribers
• $nchan_stub_status_redis_pending_commands
• $nchan_stub_status_redis_connected_servers
• $nchan_stub_status_total_ipc_alerts_received
• $nchan_stub_status_ipc_queued_alerts
• $nchan_stub_status_total_ipc_send_delay
• $nchan_stub_status_total_ipc_receive_delay