LogicMachine as gateway between RTI and KNX

if not ready then
  require('copas')
 
  -- list of client sockets
  clients = {}
 
  -- incoming data handler
  function datahandler(sock, data)
    local ip, port
    ip, port = sock:getpeername()
 
    _,_,command,address,datatype,value = string.find(data, "^#RTI_Control#@([^@]+)@%%([^%%]+)%%%$([^%$]*)%$~([^~]*)~")
 
    -- send reply
    if value == 'HELLO' then
      sock:send('#RTI_Control#@HEARTBEAT@%SYSTEM%$STRING$~HELLO TO YOU~\r\n')
    end
    if command == 'BUTTON' then
      --Button pressed. Call for function
      pushbutton(address, value)
    end
    if command == 'WRITEADDRESS' then
      --Write received value into group address
      grp.write(address, value)
    end
    if command == 'READSTRING' then
      --String value request
      value = updatestring(address)
      if value ~= nil then
        udpsend("UPDATESTRING",address,"STRING",value)
      end
    end
    if command == 'READBUTTON' then
      --Button status request
      value = updatebutton(address)
      if value ~= nil then
        udpsend("UPDATEBUTTON",address,"BOOLEAN",value)
      end
    end
    if command == 'READADDRESS' then
      --Group address status request
      value = grp.getvalue(address)
      if value ~= nil then
        if type(value) == 'boolean' and datatype == 'BOOLEAN' then
          udpsend("UPDATEADDRESS",address,"BOOLEAN",(value and 1 or 0))
        elseif type(value) == 'integer' and datatype == 'INTEGER' then
          udpsend("UPDATEADDRESS",address,"INTEGER",value)
        end
      end
    end
  end
 
  -- connection handler
  function 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('[server] connection from %s', id)
 
    -- save socket reference
    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('[server] closed connection from %s:%d', ip, port)
        -- remove socket reference
        clients[ id ] = nil
        return
      end
 
      -- handle data frame
      datahandler(sock, data)
    end
  end
 
  -- bind to port 6789
  tcpserver = socket.bind('*', 6789)
 
  -- error while binding, try again later
  if not tcpserver then
    os.sleep(5)
    error('[server] error: cannot bind')
  end
 
  -- set server connection handler
  copas.addserver(tcpserver, connhandler)
 
  -- create local udp server on port 12345
  udpserver = socket.udp()
  udpserver:setsockname('127.0.0.1', 12345)
  udpserver:settimeout(0.1)
 
  ready = true
end
 
-- perform server tasks for one second (5 x (0.1 + 0.1))
for i = 1, 5 do
  message = udpserver:receive()
 
  -- got message from udp, send to all active clients
  if message then
    --alert(message)
    for id, sock in pairs(clients) do
      sock:send(message .. '\r\n')
    end
  end
 
  copas.step(0.1)
end