Generic TCP Server for external requests

Code:
require('copas')



--[[

Resident script for TCP server

Manage client connexions

Receive requests from clients

Also send events through tcpQ storage



debug variables are set in the user library

]]--



--communication port to listen on

local tcp_port = 6789



if (tcp_debug) then

  alert ("TCP Server start")

end





-- send a message to the peers

function tcp_sendmessage(message)

  if (tcp_debug_tcp) then

    alert ("tcp_sendmessage : ".. message)

     end

  for id, sock in pairs(tcp_clients) do

    sock:send(message .. '\r\n')

  end

end



    

-- incoming data handler, manage each message sent by clients to LM

function tcp_datahandler(sock, data)

  local ip, port

  ip, port = sock:getpeername()

    

  if tcp_debug_tcp then

    alert('tcp_datahandler receive data from %s:%d - %s', ip, port, data)

  end



-- add your code to process data



end





-- connection handler, manage new peers

function tcp_connhandler(sock)



  -- enable keep-alive to check for disconnect events

  sock:setoption('keepalive', true)



  local ip, port, data, err, id



  -- get ip and port from socket

  ip, port = sock:getpeername()



  -- client id

  id = string.format('%s:%d', ip, port)



  alert('tcp_connhandler connection from %s', id)



  -- save socket reference

  tcp_clients[ id ] = sock



  -- main reader loop

  while true do

    -- wait for single line of data (until \n, \r is ignored)

    data, err = copas.receive(sock, '*l')



    -- error while receiving

    if err then

      alert('tcp_connhandler closed connection from %s:%d', ip, port)

      -- remove socket reference

      tcp_clients[ id ] = nil

      return

    end



    -- handle data frame

    tcp_datahandler(sock, data)

  end

end







-- init server handler

if not tcp_ready then

  

  if (tcp_debug) then

    alert ("TCP Server init start")

  end



     -- list of client sockets

  tcp_clients = {}



  --variable for the queue

  tcp_Q = {}

  --empty the storage queue

  storage.set('tcpQ', tcp_Q)



  -- bind to port

  tcp_tcpserver = socket.bind('*', tcp_port)



  -- error while binding, try again later

  if not tcp_tcpserver then

    os.sleep(5)

    error('tcp server realization init error: cannot bind')

  end



  -- set server connection handler

  copas.addserver(tcp_tcpserver, tcp_connhandler)



  tcp_ready = true

  

  if (tcp_debug) then

    alert ("TCP Server init end")

     end

end



-- loop to manage packets

while true do



  --retreive the queue

  tcp_Q = storage.get('tcpQ')

  storage.set('tcpQ', {})



  --sending the queue

  for index, value in ipairs(tcp_Q) do

    if tcp_debug then

         alert("TCP Server sending item "..tostring(index).." : "..tostring(value))

    end

    tcp_sendmessage(value)

  end



  --wait for tcp request during 0.1s

  copas.step(0.1)

end



if (tcp_debug) then

  alert ("TCP Server closed")

end