boazsegev/The Priceless Ruby Websocket.md

## config.ru
# The Rack Application container
module MyRackApplication
  # Rack applications use the `call` callback to handle HTTP requests.
  def self.call(env)
    # if upgrading...
    if env['HTTP_UPGRADE'.freeze] =~ /websocket/i
      # We can assign a class or an instance that implements callbacks.
      # We will assign an object, passing it the request information (`env`)
      env['upgrade.websocket'.freeze] = MyWebsocket.new(env)
      # Rack responses must be a 3 item array with [status, {http: :headers}, ["response body"]]
      return [0, {}, []]
    end
    # a semi-regualr HTTP response
    out = File.open File.expand_path('../index.html', __FILE__)
    [200, { 'X-Sendfile' => File.expand_path('../index.html', __FILE__), 'Content-Length' => out.size }, out]
  end
end

# The Websocket Callback Object
class MyWebsocket
  # this is optional, but I wanted the object to have the nickname provided in
  # the HTTP request
  def initialize(env)
    # we need to change the ASCI Rack encoding to UTF-8,
    # otherwise everything with the nickname will be a binary "blob" in the
    # Javascript layer
    @nickname = env['PATH_INFO'][1..-1].force_encoding 'UTF-8'
  end

  # A classic websocket callback, called when the connection is opened and
  # linked to this object
  def on_open
    puts 'We have a websocket connection'
    # iodine supports native pub/sub, using subscribe we listen to incoming data on the chat channel
    subscribe channel: "chat"
  end

  # A classic websocket callback, called when the connection is closed
  # (after disconnection).
  def on_close
    puts "Bye Bye... #{count} connections left..."
  end

  # A server-side niceness, called when the server if shutting down,
  # to gracefully disconnect (before disconnection).
  def on_shutdown
    write 'The server is shutting down, goodbye.'
  end

  def on_message(data)
    puts "got message: #{data} encoded as #{data.encoding}"
    # iodine supports native pub/sub, using publish we broadcast the data to "chat"
    publish channel: "chat", message: "#{@nickname}: #{data}"
  end
end

# iodine supports Redis out of the Box
# this extends the idea of "upgrade.websocket" and allows offloading IO events to the server's IO handling logic
if ENV["REDIS_URL"]
  uri = URI(ENV["REDIS_URL"])
  Iodine.default_pubsub = Iodine::PubSub::RedisEngine.new(uri.host, uri.port, 0, uri.password)
else
  puts "* No Redis, it's okay, pub/sub will support the process cluster."
end


# `run` is a Rack API command, telling Rack where the `call(env)` callback is located.
run MyRackApplication

## gemfile
# The Iodine Server
gem 'iodine'

## index.html
<!DOCTYPE html>
<html>
<head>
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.4/jquery.min.js"></script>
    <script>
        ws = NaN
        handle = ''
        function onsubmit(e) {
            e.preventDefault();
            if($('#text')[0].value == '') {return false}
            if(ws && ws.readyState == 1) {
                ws.send($('#text')[0].value);
                $('#text')[0].value = '';
            } else {
                handle = $('#text')[0].value
                var url = (window.location.protocol.match(/https/) ? 'wss' : 'ws') +
                            '://' + window.document.location.host +
                            '/' + $('#text')[0].value
                ws = new WebSocket(url)
                ws.onopen = function(e) {
                    output("<b>Connected :-)</b>");
                    $('#text')[0].value = '';
                    $('#text')[0].placeholder = 'your message';
                }
                ws.onclose = function(e) {
                    output("<b>Disonnected :-/</b>")
                    $('#text')[0].value = '';
                    $('#text')[0].placeholder = 'nickname';
                    $('#text')[0].value = handle
                }
                ws.onmessage = function(e) {
                    output(e.data);
                }
            }
            return false;
        }
        function output(data) {
            $('#output').append("<li>" + data + "</li>")
            $('#output').animate({ scrollTop:
                        $('#output')[0].scrollHeight }, "slow");
        }
    </script>
    <style>
    html, body {width:100%; height: 100%; background-color: #ddd; color: #111;}
    h3, form {text-align: center;}
    input {background-color: #fff; color: #111; padding: 0.3em;}
    </style>
</head><body>
  <h3>The Ugly Chatroom POC</h3>
    <form id='form'>
        <input type='text' id='text' name='text' placeholder='nickname'></input>
        <input type='submit' value='send'></input>
    </form>
    <script> $('#form')[0].onsubmit = onsubmit </script>
    <ul id='output'></ul>
</body>
</html>

## The Priceless Ruby Websocket.md

      
    Raw
  

              The Priceless Ruby Websocket.md
            
          
    A proof of concept for Rack's env['rack.websocket']

This is a proof of concept for Rack based Websocket connections, showing how the Rack API can be adjusted to support server native real-time connections.
The chosen proof of concept was the ugliest chatroom I could find.
Although my hope is that Rack will adopt the concept and make env['rack.websocket?'] and env['rack.websocket'] part of it's standard, at the moment it's an Iodine specific feature, implemented using env['iodine.websocket'].
Install

Install required gems using:
bundler install
Run

Run this application single threaded:
bundler exec iodine -- -www ./
Or both multi-threaded and forked (you'll notice that pub/sub works across process boundaries, Redis is only required for multi-machine pub/sub).
bundler exec iodine -- -www ./ -t 16 -w 4
Further reading


rack/rack#1093


https://bowild.wordpress.com/2016/07/31/the-dark-side-of-the-rack


https://github.com/boazsegev/iodine
	# The Rack Application container
	module MyRackApplication
	# Rack applications use the `call` callback to handle HTTP requests.
	def self.call(env)
	# if upgrading...
	if env['HTTP_UPGRADE'.freeze] =~ /websocket/i
	# We can assign a class or an instance that implements callbacks.
	# We will assign an object, passing it the request information (`env`)
	env['upgrade.websocket'.freeze] = MyWebsocket.new(env)
	# Rack responses must be a 3 item array with [status, {http: :headers}, ["response body"]]
	return [0, {}, []]
	end
	# a semi-regualr HTTP response
	out = File.open File.expand_path('../index.html', __FILE__)
	[200, { 'X-Sendfile' => File.expand_path('../index.html', __FILE__), 'Content-Length' => out.size }, out]
	end
	end

	# The Websocket Callback Object
	class MyWebsocket
	# this is optional, but I wanted the object to have the nickname provided in
	# the HTTP request
	def initialize(env)
	# we need to change the ASCI Rack encoding to UTF-8,
	# otherwise everything with the nickname will be a binary "blob" in the
	# Javascript layer
	@nickname = env['PATH_INFO'][1..-1].force_encoding 'UTF-8'
	end

	# A classic websocket callback, called when the connection is opened and
	# linked to this object
	def on_open
	puts 'We have a websocket connection'
	# iodine supports native pub/sub, using subscribe we listen to incoming data on the chat channel
	subscribe channel: "chat"
	end

	# A classic websocket callback, called when the connection is closed
	# (after disconnection).
	def on_close
	puts "Bye Bye... #{count} connections left..."
	end

	# A server-side niceness, called when the server if shutting down,
	# to gracefully disconnect (before disconnection).
	def on_shutdown
	write 'The server is shutting down, goodbye.'
	end

	def on_message(data)
	puts "got message: #{data} encoded as #{data.encoding}"
	# iodine supports native pub/sub, using publish we broadcast the data to "chat"
	publish channel: "chat", message: "#{@nickname}: #{data}"
	end
	end

	# iodine supports Redis out of the Box
	# this extends the idea of "upgrade.websocket" and allows offloading IO events to the server's IO handling logic
	if ENV["REDIS_URL"]
	uri = URI(ENV["REDIS_URL"])
	Iodine.default_pubsub = Iodine::PubSub::RedisEngine.new(uri.host, uri.port, 0, uri.password)
	else
	puts "* No Redis, it's okay, pub/sub will support the process cluster."
	end


	# `run` is a Rack API command, telling Rack where the `call(env)` callback is located.
	run MyRackApplication
	<!DOCTYPE html>
	<html>
	<head>
	<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.4/jquery.min.js"></script>
	<script>
	ws = NaN
	handle = ''
	function onsubmit(e) {
	e.preventDefault();
	if($('#text')[0].value == '') {return false}
	if(ws && ws.readyState == 1) {
	ws.send($('#text')[0].value);
	$('#text')[0].value = '';
	} else {
	handle = $('#text')[0].value
	var url = (window.location.protocol.match(/https/) ? 'wss' : 'ws') +
	'://' + window.document.location.host +
	'/' + $('#text')[0].value
	ws = new WebSocket(url)
	ws.onopen = function(e) {
	output("<b>Connected :-)</b>");
	$('#text')[0].value = '';
	$('#text')[0].placeholder = 'your message';
	}
	ws.onclose = function(e) {
	output("<b>Disonnected :-/</b>")
	$('#text')[0].value = '';
	$('#text')[0].placeholder = 'nickname';
	$('#text')[0].value = handle
	}
	ws.onmessage = function(e) {
	output(e.data);
	}
	}
	return false;
	}
	function output(data) {
	$('#output').append("<li>" + data + "</li>")
	$('#output').animate({ scrollTop:
	$('#output')[0].scrollHeight }, "slow");
	}
	</script>
	<style>
	html, body {width:100%; height: 100%; background-color: #ddd; color: #111;}
	h3, form {text-align: center;}
	input {background-color: #fff; color: #111; padding: 0.3em;}
	</style>
	</head><body>
	<h3>The Ugly Chatroom POC</h3>
	<form id='form'>
	<input type='text' id='text' name='text' placeholder='nickname'></input>
	<input type='submit' value='send'></input>
	</form>
	<script> $('#form')[0].onsubmit = onsubmit </script>
	<ul id='output'></ul>
	</body>
	</html>