key value store, the humble beginnings

keystore.lua

local config = { host="localhost", port=6379 }
local socket = require("socket")
local server = assert(socket.bind(config.host, config.port))
local ip, port = server:getsockname()
print(string.format("listening on %s:%s", ip, port))
 
local store = {}

local function add(key, value)
   store[key] = value
   return "OK"
end

local function get(key)
   local value = store[key]
   if value then
      return value
   else
      return "NULL"
   end
end

local function del(key)
   local value = store[key]
   store[key] = nil
   if value then 
      return value
   else
      return "NULL"
   end
end

local function processEvent(request)
   local command,data = string.match(request, "(%a%a%a) (.+)")
   if command == "GET" then
      local key = string.match(data, "/([^/]+)")
      if key then
         r = get(key)
         print(string.format("key: %s returned value: %s", key, r))
      end
   elseif command == "PUT" then
      local key,value = string.match(data, "/([^/]+)/(.+)")
      if key and value then 
         r = add(key, value) 
         print(string.format("key: %s insert value: %s", key, value))
      end
   end
   if not r then
      print("invalid request")
      return "NULL"
   else
      return r
   end
end

local function main()
   while true do
      local client = server:accept()
      client:settimeout(10)
      local request, err = client:receive()
      if not err then 
         local response = processEvent(request)
         client:send(response .. "\n")  
      end
      client:close()
   end
end

main()