RFID Door Lock

os.loadAPI("StrUtils")

    function inFile(file, string)

      local f = fs.open(file,"r")
      local line

      repeat
        line = f.readLine()
        if string==line then
          f.close()
          return true
        end
      until not line

      f.close()
      return false

    end

readerSide = "back"
writerSide = "left"
redstoneSide = "top"

lastTimer = {}

    reader = peripheral.wrap(readerSide)
    print("Door Contol is running")
    while true do
        reader.scan() --Creats an "rfid_detected" when a card is in range
        event, p1, p2 = os.pullEvent()
        if event == "rfid_detected" then
            if inFile("//.keys", StrUtils.SHA1(p1)) and p2 < 3 then
                rs.setOutput(redstoneSide, true)
                lastTimer = os.startTimer(0.5)
            end
        elseif event == "timer" and lastTimer == p1 then
            rs.setOutput(redstoneSide, false)
        end
    end