nats-socket.io

NATS Socket.io proxy

Usage

Docker

docker run --rm -d -p 80:80 \
  -e "NATS_HOSTNAME=example.com" \
  -e "NATS_PORT=4222" \
  -e "WS_PATH=/socket.io" \
  -e "WS_ORIGINS=*" \
  bigslycat/nats-socket.io:latest

Docker Compose

version: '3.7'
services:
  nats-proxy:
    image: bigslycat/nats-socket.io:latest
    environment:
      NATS_HOSTNAME: example.com
      NATS_PORT: 4222
      WS_PATH: /socket.io
      WS_ORIGINS: '*'

Environment variables

Name	Default value	Description
NATS_HOSTNAME	localhost	NATS server hostname
NATS_PORT	4222	NATS server port
NATS_USER		NATS user
NATS_PASSWORD		NATS password
NATS_TOKEN		NATS connection authorization token
WS_PATH	/socket.io	Name of the path to capture WS
WS_ORIGINS	*	Access-Control-Allow-Origin header value

Events

NATS incoming messages

All of NATS incoming messages have data object JSON with properties:

• headers — headers of WS client connection.
• cookies — cookies of WS client connection.
• webSocketId — unique id of WS client connection.

NATS incoming messages list

• web client / connected — emits after web client connected to server.
• web client / disconnected — emits after web client disconnected to server.
• web client / error — emits when something went wrong after web client message. Additional properties:
  • kind — error kind.
  • message — raw incoming data value. It may not be an object, because it may depend on a possibly wrong client IO.
• from web client <webSocketId> / <subject> — emits after web client sends a message. Additional properties:
  • payload — payload data of message. Optional.

NATS outgoing messages

• to web client <webSocketId> / <Socket.io event name> — forwards to Socket.io connection as <Socket.io event name>.

Socket.io outgoing messages

• message — send message to NATS. Arguments:
  1. string | Object, required — message subject or object with properties:
     • subject, string, required — message subject.
     • payload, optional — message payload.
  2. reply — callback function for reply from NATS.