client.rb

require 'socket'
require 'gosu'

class GameWindow < Gosu::Window
  def initialize
    super 640, 480, false
    self.caption = "Client"
    @image = Gosu::Image.new(self,"headcrab.bmp",false)
    @x, @y = get("x"), get("y")
  end

  def start
    @server = UDPSocket.new
    @server.bind("25.50.161.112", 7501)
    @thread_accept = Thread.new {
      running = true
      while running
        puts "received socket"
        content, sender = @server.recvfrom(16)
        puts content
      end
    }
  end

  def update
    @x, @y = get("x"), get("y")
  end

  def draw
    @image.draw(@x.to_i, @y.to_i, 5)
  end

  def get(key)
    request("GET #{key}")
  end

  def set(key)
    request("SET #{key}")
  end

  def request(string)
    @client = UDPSocket.new
    @client.send(string, 0, "25.50.161.112",7500)
  end

  def button_down(id)
    case id
    when Gosu::KbLeft
      set("left true")
    when Gosu::KbRight
      set("right true")
    end
  end

  def button_up(id)
    case id
    when Gosu::KbLeft
      set("left false")
    when Gosu::KbRight
      set("right false")
    end
  end
end

@game = GameWindow.new
@game.start
@game.show

server.rb

require 'socket'

class Server
  def initialize(port)
    @server = UDPSocket.new
    @server.bind("25.50.161.112", port)
    puts "Server listening on #{@server.local_address.ip_port}"
    @storage = {"x" => 250, "y" => 250, "left" => false, "right" => false}
  end

  def start
    @thread_update = Thread.new { 
    running = true
    while running
      sleep(0.0167)
      update 
    end 
  }

    @thread_accept = Thread.new {
      running = true
      while running
        puts "sent socket 1"
        content, sender = @server.recvfrom(16)
        puts "sent socket 2"
        @sender = UDPSocket.new
        @sender.send(process(content), 0, sender[3], 7500)
        puts "sent socket 3"
      end
    }

    @thread_update.join
    @thread_accept.join
  end

  def process(request)
    case command.upcase
    when 'GET'
      @storage[key]
    when 'SET'
      @storage[key] = value
    end
  end

  def update
    if @storage["left"] == "true"
      @storage["x"] -= 0.5
    elsif @storage["right"] == "true"
      @storage["x"] += 0.5
    end
  end
end

@server = Server.new(7500)
@server.start