OpenComputers - NET API

--[[
    Wireless-Modem-API

  This is a simple interface for wireless modems and makes use
  of the DNS servers that you have to set up seperately.

  With this you can register an URL at the specific DNS server so
  other clients can look up your long modem address just by entering
  your URL. (e.g. "google.mc" > "abcd-2q3as-2qejh-ßjadf-blah")

  By Piorjade
]]

--CONFIGURATION

local conf =  {
  _DNS = "",             -----ENTER THE ADDRESS OF THE DNS SERVER'S MODEM!!!
  _PORT = 8080,            -----PORT MUST BE SAME AS THE PORT OF THE DNS SERVER!
}

--CONFIGURATION END

local component = require("component")
local computer = require("computer")
local ser = require("serialization")
local event = require("event")
local os = require("os")

local COMMMANDS = {
  registerURL = "rURL",
  deleteURL = "dURL",
  getAddress = "gADDR",
  getURL = "gURL",
  getAll = "gAll",
}

local errorMessages = {
  DNS_URL_NOT_FOUND = true,
  DNS_DELETE_FAILED = true,
  DNS_ADDR_NOT_FOUND = true,

}

local card
for addr, a in component.list("modem") do
  card = component.proxy(addr)
  break
end
if not card then return error("no card detected") end
local net = {}

card.open(conf._PORT) --open up the port
if not card.isOpen(conf._PORT) then print("FAILED TO OPEN PORT!") return end

net.foundServer = nil
function net.listenForDNS()
  net.foundServer = nil
  local _, myAddr, sAddr, port, distance, msg, meta = event.pull("modem_message", nil, nil, nil, nil, "DNS_SERVER")
  if port == conf._PORT and msg == "DNS_SERVER" and meta then
    meta = ser.unserialize(meta)
    if meta.type == "dns_server" then
      net.foundServer =  {type = "dns_server", host = meta.host, address = sAddr}
    end
  end
end

function net.registerURL(URL)
  if conf._DNS ~= nil then
    card.send(conf._DNS, conf._PORT, "rURL", URL)
    local _, myAddr, sAddr, port, distance, msg, meta = event.pull(2, "modem_message", nil, conf._DNS)
    if _ and port == conf._PORT and sAddr == conf._DNS then
      if not errorMessages[msg] then
        return true, msg
      else
        return false, msg
      end
    elseif not _ then
      return false, "NO_RESPONSE"
    end
  else
    return false, "NO_DNS"
  end
end

function net.removeURL(URL)
  if conf._DNS ~= nil then
    card.send(conf._DNS, conf._PORT, "dURL", URL)
    local _, myAddr, sAddr, port, distance, msg, meta = event.pull(2, "modem_message", nil, conf._DNS)
    if _ and port == conf._PORT and sAddr == conf._DNS then
      if not errorMessages[msg] then
        return true, msg
      else
        return false, msg
      end
    elseif not _ then
      return false, "NO_RESPONSE"
    end
  else
    return false, "NO_DNS"
  end
end

function net.setDNS(addr)
    conf._DNS = addr
end

function net.getDNS()
    return conf._DNS
end

function net.getPort()
    return conf._PORT
end

function net.setPort(port)
    if type(port) == "number" then
        card.close(conf._PORT)
        conf._PORT = port
        card.open(conf._PORT)
    end
end

function net.getCard()
    return card
end

function net.resolve(address)
  if conf._DNS ~= nil then
    card.send(conf._DNS, conf._PORT, "gADDR", address)
    local _, myAddr, sAddr, port, distance, msg, meta = event.pull(2, "modem_message", nil, conf._DNS)
    if _ and port == conf._PORT and sAddr == conf._DNS then
      if not errorMessages[msg] then
        return true, msg
      else
        return false, msg
      end
    elseif not _ then
      return false, "NO_RESPONSE"
    end
  else
    return false, "NO_DNS"
  end
end

function net.getURL(address)
  if conf._DNS ~= nil then
    card.send(conf._DNS, conf._PORT, "gURL", address)
    local _, myAddr, sAddr, port, distance, msg, meta = event.pull(2, "modem_message", nil, conf._DNS)
    if _ and port == conf._PORT and sAddr == conf._DNS then
      if not errorMessages[msg] then
        return true, msg
      else
        return false, msg
      end
    elseif not _ then
      return false, "NO_RESPONSE"
    end
  else
    return false, "NO_DNS"
  end
end

function net.getALL()
  if conf._DNS ~= nil then
    card.send(conf._DNS, conf._PORT, "gAll")
    local _, myAddr, sAddr, port, distance, msg, meta = event.pull(2, "modem_message", nil, conf._DNS)
    if _ and port == conf._PORT and sAddr == conf._DNS then
      if not errorMessages[msg] then
        return true, ser.unserialize(msg)
      else
        return false, msg
      end
    elseif not _ then
      return false, "NO_RESPONSE"
    end
  else
    return false, "NO_DNS"
  end
end

return net