http://stackoverflow.com/questions/13654069/non-blocking-ruby-unixsocket

1-ruby_socket.rb

# Blocks while a client is connected, and does not time out automatically
require 'socket'
require 'etc'

Socket.unix_server_loop("/tmp/sock") do |socket|
  begin
    login = Etc.getpwuid(socket.getpeereid.first).name
    puts "#{login} connected"
    input = socket.gets.strip
    puts "#{login} sent #{input}"
    socket.puts 'OK'
  ensure
    socket.close
  end
end

2-em_socket.rb

# Cannot access connecting clients UID in event machine socket :(
require 'eventmachine'

module Handler
  def post_init
    log "Got connection!"
    @login = '' # How can I get the connected UID?
  end

  def receive_data data
    @data_received ||= ""
    @data_received << data
    if @data_received.include?("\n")
      puts "#{@login} #{@data_received.split("\n").first}"
      send_data 'OK' and close_connection_after_writing
    end
  end
end

EventMachine.run do
  socket_path = '/tmp/sock'
  EventMachine.start_server socket_path, Handler
  puts "Now accepting connections at #{socket_path}"
end

3-cell_socket.rb

# Celluloid example. Multiple connections work without problems, but the actors do not terminate properly and I need a kill -9

require 'socket'
require 'etc'
require 'Celluloid'

class Connection
  include Celluloid
  attr_reader :socket
  def initialize(socket)
    @socket = socket
    @login = Etc.getpwuid(socket.getpeereid.first).name
  end

  def listen
    input = socket.gets.strip
    puts "#{@login} : #{input}"
    socket.puts "OK"
  ensure
    socket.close
    Actor.current.terminate
  end
end


Socket.unix_server_loop("/tmp/sock") do |socket|
  puts 'got connection'
  Connection.new(socket).async.listen
  puts "listening (again)"
end

4-ruby_socket-with_timeout.rb

require 'socket'
require 'etc'
require 'timeout'

# Using timeout class as suggested by @bjhaid on SO. 
# Will block while connected, but processes further requests after previous time out or send.
# Blocking could be remedied by forking or threading the processing code manually.
Socket.unix_server_loop("/tmp/sock") do |socket|
  begin
    login = Etc.getpwuid(socket.getpeereid.first).name
    puts "#{login} connected"

    Timeout.timeout 3 do
      input = socket.gets.strip
      puts "#{login}: #{input}"
      socket.puts "OK"
    end
  rescue Timeout::Error
    puts "Timeout"
    socket.puts "TIMEOUT"
  ensure
    socket.close
  end
end