NetworkAPI.lua

local component = require("component")
local event = require("event")
local modem = component.modem
local keyboard = require("keyboard")
local DNSAddress = "9955471e-b28f-4001-9d66-79c28c75be2d"
local getGUIDPort = 60
local addComputerPort = 50

--local pullArray = {}
--local port = 1  --TEST VALUE, PUT SOMETHING HERE
--local timeout = 15

function OpenModem(port)
  modem.open(port)
  if modem.isOpen(port) then
    print("Successfully opened port " .. port)
  else
    print("Could not open port " .. port .. ", closing server")
  end
end

function Quit()
  for i = 1,100 do
    if modem.isOpen(i) then
      modem.close(i)
      print("Closing port " .. i)
    end
    i = i + 1
  end
  os.exit()
end

function EventPull(timeout)
  for i=1,10 do
    local type, _, foreignAddress, port, distance, message = event.pull(timeout)
    local pullArray = {}
    if type == "key_down" then
      if keyboard.isAltDown() then
        Quit()
      end
    elseif type == "modem_message" then
      pullArray[1] = type
      pullArray[2] = foreignAddress
      pullArray[3] = port
      pullArray[4] = distance
      pullArray[5] = message
      print("Message has been received from DNS on port " .. port)
    end
    if pullArray[1] ~= nil then
      return pullArray
    end
    i = i + 1
  end
end

function SendACK(remoteAddress, port)
  modem.send(remoteAddress, port, "ACK")
  print("ACK has been sent to " .. remoteAddress .. " on port " .. port)
end

local function SendMessage(remoteAddress, port, message, timeout)
  local timeoutPull = {}
  while true do
    modem.send(remoteAddress, port, message)
    timeoutPull = EventPull(timeout)
    if timeoutPull[1] ~= nil then
      break
    end
  end
end

function ReadFile(filePath)
  local file = io.open(filePath, "r")
  local fileSize, _ = file:seek("end")
  file:seek("set")
  local fileString = file:read(fileSize)
  file:close()
  return fileString
end

function SaveFile(name, message)
  local filePath = "/home/" .. name
  local file = io.open(filePath, "w")
  file:write(message)
  file:close()
  print("File has been saved with path " .. filePath)
end

function GetGUID(name, timeout)
  SendMessage(DNSAddress, getGUIDPort, name, timeout)
  local GUIDArray = {}
  GUIDArray = EventPull(timeout)
  SendACK(GUIDArray[2], GUIDArray[3])
  SaveFile(name, GUIDArray[5])
  return GUIDArray[5]
end

function AddComputer(name, timeout)
  SendMessage(DNSAddress, addComputerPort, name, timeout)
  local check = GetGUID(name, timeout)
  for k,v in component.list(modem) do
    local address = k
  end
  if check == address then
    print("Computer has been added to the DNS under the name " .. name)
  else
    print("Error while adding computer, contact admin.")
end