client.rb

require 'debugger'
require 'socket'
require 'digest'
require 'json'

HOST = "0.0.0.0"
PORT = ARGV[0]
USERNAME = 'username'
PASSWORD = 'password'

include Socket::Constants
socket = Socket.new(AF_INET, SOCK_STREAM, 0)
sockaddr = Socket.pack_sockaddr_in(PORT, '0.0.0.0' )
socket.connect(sockaddr)

socket.puts "#{{request: "BEGIN"}.to_json}"
key = socket.readline.chomp
print key

hashed = Digest::MD5.hexdigest("#{USERNAME}#{PASSWORD}#{key}")
socket.puts "#{{request: "AUTHENTICATE", username: USERNAME, hash: hashed}.to_json}"





socket.close

server.rb

require 'securerandom'
require 'socket'
require 'json'

USERS = {
  "username" => "password",
  "chintanparikh" => "anotherpassword",
  "letmein" => "lastpassword"
}

CLIENTS = {}

HOSTNAME = '0.0.0.0'
PORT = ARGV[0]

include Socket::Constants
socket = Socket.new(AF_INET, SOCK_STREAM, 0)
sockaddr = Socket.pack_sockaddr_in(PORT, '0.0.0.0')
socket.bind(sockaddr)
socket.listen(5)

loop do
  Thread.start(socket.accept) do |client, addr|
    # client, addr = socket.accept
    request_hash = JSON.parse(client.readline.chomp)
    print request_hash

    case request_hash["request"]
    when "BEGIN"
      key = SecureRandom.hex(64)
      client.write key
    when "AUTHENTICATE"
      print request_hash["username"]
    end
  end
end

socket.close