AsyncCable

Very simple but functional websocket server for Rack async application.

• Works on Fibers via async.
• Threadsafe
• Supports broadcasting.
• Works with Falcon web server.
• Supports authorization with cookies/header.

Intended to use with Falcon web server or other web server based on.

Installation

Add this line to your application's Gemfile:

gem 'async_cable'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install async_cable

Usage

# config.ru
require_relative 'lib/main_cable' 
app = RackBuilder.new do
  use Rack::Session::Cookie, key: 'test.app', secret: ENV['RACK_SECRET']
  map '/cable' do
    run AsyncCable::Server.new(connection_class: MainCable)
  end
end
run app


# lib/main_cable.rb
class ChatCable < AsyncCable::Connection
  identified_as :main
  attr_reader :current_user

  def on_open
    @current_user = User.find_by id: request.session['user_id']
    reject_unauthorized if current_user.nil?
    stream_for request.params['room_name']

    logger.info { "User##{current_user.id} has joined to #{channel_name}/#{stream_name}." }
    self.class.broadcast(stream_name, message: "#{current_user.username} has joined.")
    transmit(message: "Welcome #{current_user.username}.")
  end

  def on_data(data)
    self.class.broadcast(stream_name, message: data[:message].to_s, by_who: current_user.username)
  end

  def on_close
    return if identifier.nil?

    logger.info { "User##{current_user.id} has left #{channel_name}/#{stream_name}." }
    self.class.broadcast(stream_name, message: "#{current_user.username} has left.")
  end
end

example of JS code for connecting with websocket server

  var socket = new WebSocket("ws://localhost:9292/cable");
  socket.onopen = function(_event) { 
    console.log("WebSocket connected"); 
  };
  socket.onerror = function(error) { 
    console.log("WebSocket error", error); 
  };
  socket.onclose = function(event) { 
    console.log("WebSocket closed", event.wasClean, event.code, event.reason);
  };
  socket.onmessage = function(event) { 
    console.log("WebSocket data received", JSON.parse(event.data)); 
  };

  var transmit = function (data) {
    socket.send( JSON.generate(data) );
  };
  var close = function (code, reason) {
    socket.close(code || 1000, reason);
  };

Development

Building version

gem_push=false rake release
gem push pkg/async_cable-X.Y.Z.gem

will use Semver from version 1.0.0

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/senid231/async_cable. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.

License

The gem is available as open source under the terms of the MIT License.

Code of Conduct

Everyone interacting in the AsyncCable project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.