padrino && websockets - ruby

Question

i'm looking for a way to open and use websockets from within a Padrino application. i know Padrino works with a single thread but i'm looking for a way to open websockets and share variables between its "onopen" "onclose" "onmessage" methods and Padrino controllers.
any idea how it's done ?
links i looked into:
Examples of Eventmachine usage with Padrino and Sinatra (only Sinatra worked for me)
em-websocket on GitHub
UPDATE 1:
this is my main.rb:
require 'rubygems' # <-- Added this require
require 'em-websocket'
require 'padrino-core'
require 'thin'
require File.expand_path("../config/boot.rb", __FILE__)
SOCKETS = []
EventMachine.run do # <-- Changed EM to EventMachine
# class App < Sinatra::Base
# get '/' do
# SOCKETS.each {|s| s.send "fooooo"}
# return "foo"
# end
# end
EventMachine::WebSocket.start(:host => '0.0.0.0', :port => 8080) do |ws| # <-- Added |ws|
# Websocket code here
ws.onopen {
ws.send "connected!!!!"
SOCKETS << ws
}
ws.onmessage { |msg|
puts "got message #{msg}"
ws.send "ECHO: #{msg}"
}
ws.onclose {
ws.send "WebSocket closed"
SOCKETS.delete ws
}
end
# You could also use Rainbows! instead of Thin.
# Any EM based Rack handler should do.
#App.run!({:port => 3000}) # <-- Changed this line from Thin.start to App.run!
Thin::Server.start Padrino.application, '0.0.0.0', 3000
end
i'm getting this exception:
/home/cstore/.rvm/gems/ruby-1.9.2-p290#runtime/gems/thin-1.2.11/lib/thin/daemonizing.rb:2:in `require': no such file to load -- daemons (LoadError)
from /home/cstore/.rvm/gems/ruby-1.9.2-p290#runtime/gems/thin-1.2.11/lib/thin/daemonizing.rb:2:in `<top (required)>'
from /home/cstore/.rvm/gems/ruby-1.9.2-p290#runtime/gems/thin-1.2.11/lib/thin/server.rb:50:in `<class:Server>'
from /home/cstore/.rvm/gems/ruby-1.9.2-p290#runtime/gems/thin-1.2.11/lib/thin/server.rb:48:in `<module:Thin>'
from /home/cstore/.rvm/gems/ruby-1.9.2-p290#runtime/gems/thin-1.2.11/lib/thin/server.rb:1:in `<top (required)>'
from main.rb:39:in `block in <main>'
from /home/cstore/.rvm/gems/ruby-1.9.2-p290#runtime/gems/eventmachine-0.12.10/lib/eventmachine.rb:256:in `call'
from /home/cstore/.rvm/gems/ruby-1.9.2-p290#runtime/gems/eventmachine-0.12.10/lib/eventmachine.rb:256:in `run_machine'
from /home/cstore/.rvm/gems/ruby-1.9.2-p290#runtime/gems/eventmachine-0.12.10/lib/eventmachine.rb:256:in `run'
from main.rb:9:in `<main>'
UPDATE 2:
Resolved thanks to Nathan !
I just added 'daemons' to Gemfile and reloaded my application.

Answer 1

Maybe you need to install daemons:
Edit your Gemfile:
# Adding this
gem 'daemons'
Install missing gems:
$ bundle install

Answer 2

What in particular from this example: https://github.com/igrigorik/em-websocket and Any success with Sinatra working together with EventMachine WebSockets? didn't work with Padrino but did with Sinatra? Can you explain the errors you got and why those examples failed (stacktraces)? Maybe we can help investigate.

Answer 3

I ran across this post and it helped me a bit, but I wanted to offer an alternative solution to anyone else who might stumble upon it. I chose to just directly modify the config.ru and mount a websocket-rack application.
Here's my config.ru where WSApp is a subclass of Rack::WebSocket::Application and is placed in the lib/ directory (therefore being automatically loaded by Padrino):
#!/usr/bin/env rackup
# encoding: utf-8
# This file can be used to start Padrino,
# just execute it from the command line.
require File.expand_path("../config/boot.rb", __FILE__)
# Setup routes
map '/' do
run Padrino.application
end
map '/ws' do
run WSApp.new
end

Answer 4

Since this is the top hit in Google right now, I'd like to link it to padrino-websockets, a clean DSL for writing websockets applications in Padrino.