RocketWS

RocketWS is open-sourced WebSockets push server based on gevent-websocket library

Usage

JavaScript side (to connect clients)

// Create WebSocket JS instance and add onmessage handler
var ws = new WebSocket('ws://localhost:58000');  // for secure connections use wss://
ws.onmessage = function (event) {
  console.log('Received data: ' + event.data);
}; 

// add other handlers: onconnect, onerror, etc

// subscribe to a channel chat
request = {id: 0, jsonrpc: '2.0', method: 'subscribe', params: {channel: 'chat'}}
ws.send(JSON.stringify(request));

// send data to a channel chat
request = {id: 0, jsonrpc: '2.0', method: 'send_data', params: {channel: 'chat', data: {x: 1, y: 2}}}
ws.send(JSON.stringify(request));

// unsubscribe
request = {id: 0, jsonrpc: '2.0', method: 'unsubscribe', params: {channel: 'chat'}}
ws.send(JSON.stringify(request));

Python side (to send messages to clients)

import requests

# emit message to a chat
data = {"id": 0, "jsonrpc": "2.0", "method": "emit", "params": {"channel": "chat", "data": {"message": "hola!"}}}
resp = requests.post('http://localhost:59999', json=data)

print(resp.text)
>>> {'jsonrpc': '2.0', 'result': 'emitted: 0', 'id': 0}

Features

• Free easy-use asynchronous standalone WebSockets server, allows to build cutting edge web-applications;
• All interactions are based on JSON-RPC 2.0 Specification;
• Unlimited subscribe channels;
• Scalable software design;
• Supports command-line interface;
• Flexible deployment schemas (direct, with supervisor, with docker);

Workflow

Request examples

All requests must be correspond to JSON-RPC 2.0 Specification

• WebSockets

  • Subscribe to channel chat: {"id": 0, "jsonrpc": "2.0", "method": "subscribe", "params": {"channel": "chat"}}

  • Unsubscribe from channel chat: {"id": 0, "jsonrpc": "2.0", "method": "unsubscribe", "params": {"channel": "chat"}}

  • Send data to channel chat: {"id": 0, "jsonrpc": "2.0", "method": "send_data", "params": {"channel": "chat", "data": {"message": "hola!"}}}

• Transport messages (send from backend)

  • Emit message for all subscribers for channel chat: {"id": 0, "jsonrpc": "2.0", "method": "emit", "params": {"channel": "chat", "data": {"message": "hola!"}}}
  • Notify all subscribers (some system messages): {"id": 0, "jsonrpc": "2.0", "method": "notify_all", "params": {"data": {"message": "Broadcase system message"}}}

Command line interface (RocketWS shell)

Command line interface is console for WebSockets clients interaction, this feature emulate transport connector with console. So you will be able to emulate backend client to send messages to websockets clients

• Run shell: make shell
• Type help for more information

NOTE: For remote shell you need to ensure that port for TRANSPORT is available on a server.

Run remote shell: python manage.py shell --transport http://rocketws.domain.com:80/shell

Configuration

Common and recommended settings are already predefined. Otherwise you can configure it with manage.py command. See more information in Management section.

There are several parameters:

• TRANSPORT -- backend transport parameters. Default port: 59999

• WEBSOCKETS -- control WebSockets server parameters for clients interaction. Default port: 58000

• LOGGING -- logging configuration

Management

Main application management available with manage.py script.

Commands:

• runserver - Start RocketWS
• tests - Run tests
• shell - Run command-line interface

Options:

• --ws-conn - WebSockets server connection options. Example: --ws-conn 0.0.0.0:58000 or --ws-conn :58000. Options for runserver command.
• --transport - Backend transport connection options. Example: --transport 0.0.0.0:59999. Options for runserver and shell command.

Installation/Deployment

Dependencies

Make sure that you have libevent-2.0-5 or libev4 in your system.

Develop way

• Clone repo: git clone https://github.com/prawn-cake/RocketWS.git {dir}
• Run it: make run

Supervisor way

• Clone repo: git clone https://github.com/prawn-cake/RocketWS.git {dir}
• Install supervisor: sudo aptitude install supervisor (Debian-way)
• Add supervisor config: sudo vim /etc/supervisor/conf.d/rocketws.conf

NOTE: For production using need to create log directory /var/log/rocketws

    [program:rocketws]
    command={dir}/.env/bin/python {dir}/manage.py runserver --ws-conn 0.0.0.0:58000 --transport 0.0.0.0:59999
    autostart=false
    autorestart=true
    user={str:user}
    stdout_logfile=/{path_to_log_dir}/rocketws.log
    

• Update supervisor configurations: sudo supervisorctl reread && sudo supervisorctl update
• Start RocketWS with: sudo supervisorctl restart rocketws

Docker way

NOTE: Docker works fine (without any workarounds) only under x86_64 arch

• Install docker
• Add DOCKER_OPTS="--ip 127.0.0.1" to /etc/default/docker (or /etc/sysconfig/docker for RHEL) and restart the docker service

NOTE: use sudo with the following commands or add your user to a docker group

• docker pull prawncake/rocketws
• docker run --name rocketws -it -p 58000:58000 -p 59999:59999 prawncake/rocketws /bin/bash
• You will be attached to the container, run application in the background with make run_bg
• Detach from the container with Ctrl+p Ctrl+q

NOTE: For some reasons docket can't run nohup, disown, & shell instructions from command line or within Makefile commands

Container will be started and then you can connect to tcp:58000 for WebSockets and to tcp:59999 for backend transport

Brief docker howto

• Attach to rocketws container: docker attach rocketws
• Detach from the container: Ctrl+p Ctrl+q
• List of running containers: docker ps -a
• Stop/start/remove container: docker {start|stop|rm} rocketws

NOTE: We use exact name because we set it up in run command as a --name option otherwise we must use container ID

• More command-line docs

Chef way

• Just use rocketws chef cookbook

Nginx proxy

Useful for production

• Nginx websocket proxying article

• Add custom proxy_read_timeout, because it equals 60s by default, proxy_read_timeout 604800; # one-week timeout; for example

NOTE: If you use https with self-signatured certificate you must use wss:// schema firstly and before connect you must first visit a regular html page with that certificate so you can accept it.