Playing with Sinatra streaming api.

config.ru

# encoding: utf-8
require 'bundler'

Bundler.require

require './server'

run App

Gemfile

source :rubygems
gem 'sinatra', git: 'git://github.com/sinatra/sinatra.git'
gem 'thin'

gistfile1.rb

# encoding: utf-8
require 'sinatra/base'

class Connections
  include Enumerable

  def initialize
    @connections = {}
  end

  def []=(id, connection)
    # Set on_close callback
    connection.callback { leave(id)}
    @connections[id] = connection
  end

  def [](id)
    @connections[id]
  end

  def each(&block)
    @connections.values.each &block
  end

  def delete(id)
    @connections.delete id
  end

  def join(id, connection)
    broadcast "#{id} joins"
    self[id] = connection
    send(id, "Hello #{id}")
  end

  def leave(id)
    delete id
    broadcast "#{id} left"
  end

  def send(id, message)
    self[id] << message << "\n" if self[id]
  end

  def broadcast(message)
    each {|connection| connection << message << "\n"}
  end

  def connected
    @connections.keys
  end
end

class App < Sinatra::Base
  set :port, ARGV[1] || 4567
  set :server, :thin
  connections = Connections.new

  helpers do
    def user
      @user ||= ['Gaston', 'Hervé', 'Bill', 'Totoro', 'Mei', 'Fred', 'Alex', 'Chou', 'Fleur', 'Jean'].sample
    end
  end

  get '/' do
    # stream to all users
    connections.broadcast(connections.connected)

    # stream to one perticular user
    connections.send(user, user)

    # Return list of current connected users
    connections.connected.join(', ')
  end

  get '/stream', provides: 'text/event-stream' do
    stream(:keep_open) {|connection| connections.join(user, connection) }
  end

end