HoneyryderChuck · January 16, 2023 07:28
diff --git a/chat.rb b/chat.rb
 # chat.rb
 require 'sinatra/base'
 # this also loads celluloid io, let's keep that in mind
 require 'celluloid/current'
 require 'reel'

 # The chat server, an IO Event Loop held by the actor
 # Collects connections (Reel Event Streams)
 # 
 # Contrary to EventMachine, there is no event callback for
 # when the user disconnects, writes will just fail, we 
 # therefore only remove these connections when writes fail.
 #
 class ChatServer
  include Celluloid::IO
  attr_reader :connections
  def initialize
    @connections = []
  end

  def listen(connection)
    @connections << connection
  end

  def broadcast(message)
    # TODO: improve this
    # consider that the connections has 10000 clients
    # we spend most of the team iterating and creating 10000 
    # celluloid tasks/fibers, starving resources while only do
    # stuff in the end. 
    # improvement: take it in batches of N connections, async/unicast
    # them, and then sleep, so that the allocated tasks can be run
    @connections.each do |connection|
      async(:unicast, connection, message)
    end
  end

  def unicast(connection, message)
    connection.write(message)
  rescue Reel::SocketError
    @connections.delete(connection)
  end

 end

 # Supervise all the things
 config = Celluloid::Supervision::Configuration.new
 config.define type: ChatServer, as: :chat_server
 config.deploy

 # Somehow Celluloid IO doesn't work well with sinatra classic applications, supervisor blows up. 
 class Server < Sinatra::Base
  set server: 'puma',
      chat_server: Celluloid::Actor[:chat_server]
      
  get '/' do
    halt erb(:login) unless params[:user]
    erb :chat, locals: { user: params[:user].gsub(/\W/, '') }
  end
  

  # This is the secret sauce, we just reuse the reel
  # built-in Classes to act on this. From the puma perspective,
  # we hijack the socket and pass it to the reel connection, which 
  # will later pass it to our chat server above. Puma worker is free. 
  get '/stream', provides: 'text/event-stream' do
    io = env['rack.hijack'].call
    io = ::Celluloid::IO::TCPSocket.new(io)
    writer = Reel::Response::Writer.new(io)
  
  
    event_stream = ::Reel::EventStream.new do |event_stream|
      settings.chat_server.async(:listen, event_stream)
    end
    resp = Reel::StreamResponse.new(:ok,
           {
             'Content-Type' => 'text/event-stream; charset=utf-8',
             'Cache-Control' => 'no-cache',
             'X-Accel-Buffering' => 'no'
           },
           event_stream)
  
    writer.handle_response(resp)
    resp
  end
  
  post '/' do
    settings.chat_server.async(:broadcast, "data: #{params[:msg]}\n\n")
    204 # response without entity body
  end

  template :layout do
 <<-HTML
 <html>
  <head> 
    <title>Super Simple Chat with Sinatra</title> 
    <meta charset="utf-8" />
    <script src="http://ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js"></script> 
  </head> 
  <body><%= yield %></body>
 </html>
 HTML
  end
  template :login do
 <<-HTML
 <form action='/'>
  <label for='user'>User Name:</label>
  <input name='user' value='' />
  <input type='submit' value="GO!" />
 </form>
 HTML
  end
  
  template :chat do
 <<-HTML
 <pre id='chat'></pre>

 <form>
  <input id='msg' placeholder='type message here...' />
 </form>

 <script>
  // reading
  var es = new EventSource('/stream');
  es.onmessage = function(e) { $('#chat').append(e.data + "\\n") };

  // writing
  $("form").on("submit", function(e) {
    $.post('/', {msg: "<%= user %>: " + $('#msg').val()});
    $('#msg').val(''); $('#msg').focus();
    e.preventDefault();
    return false;
  });
 </script>
 HTML
  end
 end

 # config.ru
 require_relative "chat.rb"
 run Server

 # run this with rack and puma
	# chat.rb
	require 'sinatra/base'
	# this also loads celluloid io, let's keep that in mind
	require 'celluloid/current'
	require 'reel'

	# The chat server, an IO Event Loop held by the actor
	# Collects connections (Reel Event Streams)
	#
	# Contrary to EventMachine, there is no event callback for
	# when the user disconnects, writes will just fail, we
	# therefore only remove these connections when writes fail.
	#
	class ChatServer
	include Celluloid::IO
	attr_reader :connections
	def initialize
	@connections = []
	end

	def listen(connection)
	@connections << connection
	end

	def broadcast(message)
	# TODO: improve this
	# consider that the connections has 10000 clients
	# we spend most of the team iterating and creating 10000
	# celluloid tasks/fibers, starving resources while only do
	# stuff in the end.
	# improvement: take it in batches of N connections, async/unicast
	# them, and then sleep, so that the allocated tasks can be run
	@connections.each do \|connection\|
	async(:unicast, connection, message)
	end
	end

	def unicast(connection, message)
	connection.write(message)
	rescue Reel::SocketError
	@connections.delete(connection)
	end

	end

	# Supervise all the things
	config = Celluloid::Supervision::Configuration.new
	config.define type: ChatServer, as: :chat_server
	config.deploy

	# Somehow Celluloid IO doesn't work well with sinatra classic applications, supervisor blows up.
	class Server < Sinatra::Base
	set server: 'puma',
	chat_server: Celluloid::Actor[:chat_server]

	get '/' do
	halt erb(:login) unless params[:user]
	erb :chat, locals: { user: params[:user].gsub(/\W/, '') }
	end


	# This is the secret sauce, we just reuse the reel
	# built-in Classes to act on this. From the puma perspective,
	# we hijack the socket and pass it to the reel connection, which
	# will later pass it to our chat server above. Puma worker is free.
	get '/stream', provides: 'text/event-stream' do
	io = env['rack.hijack'].call
	io = ::Celluloid::IO::TCPSocket.new(io)
	writer = Reel::Response::Writer.new(io)


	event_stream = ::Reel::EventStream.new do \|event_stream\|
	settings.chat_server.async(:listen, event_stream)
	end
	resp = Reel::StreamResponse.new(:ok,
	{
	'Content-Type' => 'text/event-stream; charset=utf-8',
	'Cache-Control' => 'no-cache',
	'X-Accel-Buffering' => 'no'
	},
	event_stream)

	writer.handle_response(resp)
	resp
	end

	post '/' do
	settings.chat_server.async(:broadcast, "data: #{params[:msg]}\n\n")
	204 # response without entity body
	end

	template :layout do
	<<-HTML
	<html>
	<head>
	<title>Super Simple Chat with Sinatra</title>
	<meta charset="utf-8" />
	<script src="http://ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js"></script>
	</head>
	<body><%= yield %></body>
	</html>
	HTML
	end
	template :login do
	<<-HTML
	<form action='/'>
	<label for='user'>User Name:</label>
	<input name='user' value='' />
	<input type='submit' value="GO!" />
	</form>
	HTML
	end

	template :chat do
	<<-HTML
	<pre id='chat'></pre>

	<form>
	<input id='msg' placeholder='type message here...' />
	</form>

	<script>
	// reading
	var es = new EventSource('/stream');
	es.onmessage = function(e) { $('#chat').append(e.data + "\\n") };

	// writing
	$("form").on("submit", function(e) {
	$.post('/', {msg: "<%= user %>: " + $('#msg').val()});
	$('#msg').val(''); $('#msg').focus();
	e.preventDefault();
	return false;
	});
	</script>
	HTML
	end
	end

	# config.ru
	require_relative "chat.rb"
	run Server

	# run this with rack and puma