TCP Socket Connection for Legrand

[a455115]

Code:

function read(sock)
  local buf = {}

  while true do
    local ch, err = sock:receive(1)

    if ch then
      local pr = buf[ #buf ]

      buf[ #buf + 1 ] = ch

      if ch == '#' and pr == '#' then
        break
      end

    else
      return nil, err
    end
  end

  local ret = table.concat(buf)
  log(ret)
  return ret
end
ACK = '*#*1##'
NACK = '*#*0##'
OPEN = '*99*1##'



function openwebnetinit()
  local socket = require('socket')
    local sock = socket.tcp()

sock:settimeout(1)

   local res, err = socket.connect('192.168.1.247', 20000)
  if not res then
    alert('connect failed ' .. tostring(err))
    return
  end

  res, err = read(sock)
  if res ~= ACK then
    alert('no initial ack ' .. tostring(res or err))
    return
  end

  sock:send(OPEN)

  res, err = read(sock)
  if not res then
    alert('no nonce ' .. tostring(err))
    return
  end

  local nonce = res:match('%d+')


  res, err = read(sock)
  if res ~= ACK then
    alert('auth failed ' .. tostring(res or err))
    return
  end

  return sock
end

sock = openwebnetinit()
if sock then
  alert('connection ok')
  -- do something here
  sock:close()
end

Code:

Resident script:5: calling 'receive' on bad self (tcp{client} expected, got userdata)
stack traceback:
[C]: in function 'receive'
Resident script:5: in function 'read'
Resident script:43: in function 'openwebnetinit'

Apparently I'm confusing something general?