Wordclock/telnet.lua

-- Telnet client 
telnetClient=nil
local lines = {}

-- Helper function
function s_output(str)
      uart.write(0,  "T:" .. tostring(str))
      if (telnetClient ~= nil) then
	if (#lines > 0) then
	    table.insert(lines, str)
	else
	    table.insert(lines, str)
	    telnetClient:send("\r") -- Send something, so the queue is read after sending
	end
      end
end

-- Telnet Server
function startTelnetServer()
    s=net.createServer(net.TCP, 180)
    s:listen(23,function(c)
	    telnetClient=c
	    node.output(s_output, 0)
	    c:on("receive",function(c,l)
	      node.input(l)
	    end)
	    c:on("disconnection",function(c)
	      node.output(nil)
	      telnetClient=nil
	    end)
	    c:on("sent", function()        
		if (#lines > 0) then
		  local line1=nil
		  for k,v in pairs(lines) do if (k==1) then 
			  line1=v 
		  	end
			uart.write(0, "Lines:" .. tostring(v) .. "\r\n")

		  end
		  if ( line1 ~= nil ) then
		   table.remove(lines, 1)
		   uart.write(0, "Telent[" .. tostring(#lines) .. "]" .. tostring(line1) .. "\r\n" )
		   telnetClient:send(line1)
		  end
		end
	    end)
	    print("Welcome to the Wordclock.")
	    print("- mydofile(\"commands\")")
	    print("- storeConfig()")
	    print("Visite https://github.com/nodemcu/nodemcu-firmware/wiki/nodemcu_api_en for further commands")
	    uart.write(0, "New client connected\r\n")
    end)
    print("Telnetserver started")
end