simple-key-value-store.rb

# Simple Key-Value store in Ruby
# Stephan Wehner, May 2017
#
# 2 sample sessions illustrate usage:
# In one terminal:
# $ ruby simple-key-value-store.rb
# In another terminal session:
#
# $ telnet localhost 3333
# Trying ::1...
# Connected to localhost.
# Escape character is '^]'.
# PUT abc 123
# OK abc
# GET abc
# 123
# PUT bbbb
# ERROR parsing PUT bbbb
# PUT bbb 3333
# OK bbb
# GET bbb
# 3333
# quit
# Connection closed by foreign host.
# $ telnet localhost 3333
# Trying ::1...
# Connected to localhost.
# Escape character is '^]'.
# GET bbb
# 3333
#######################################################

require 'socket'

server = TCPServer.new  3333

@store = {}

def handle_line(connection, line)
  if line =~ /^PUT ([[:alnum:]]+) (.*)/
    k, v = $1, $2
    @store[k] = v
    connection.puts "OK #{k}"
  elsif line =~ /^GET ([[:alnum:]]+)\s*/
    k = $1
    connection.puts @store[k]
  else
    connection.puts "ERROR parsing #{line}"
  end
end

while connection = server.accept do
  while line = connection.gets do
    break if line =~ /\Aquit/
    handle_line connection, line
  end
  connection.close
end