I'm having trouble understanding how I'm supposed to use luasocket to efficiently receive data. My application is a TCP server that waits for clients to connect and then will handle them all in parallel. I decided to go with non-blocking server socket and polling using select over all sockets: the actuall connected sockets and the listening socket.

Receive takes a parameter which is supposed to be the number of bytes it will read. If I set it to 100 and have the socket in non-blocking mode (timeout 0) then receive will return "timeout" on the second returned value and throw away the 50 bytes. Why not keep those 50 bytes for the next receive I do? Or even better why not return both the 50 bytes AND the "timeout" error?

I can make my application work if I set the receive size to 1 byte, but that means that I'll need to aggregate byte by byte in an array, and the concatenate it when I need the data.

What am I missing here?

EDIT: Here's the critical part of the code: https://pastebin.com/raw/Q9WTQUKH