A tiny line-based TCP chat server designed to relay messages between low-power embedded computers with Internet connectivity (for example, an Arduino with a ESP8266 WiFi module).

You need Python >= 2.7 and < 3 (although conversion to Python 3 would be trivial).

Just run "python esprelay.py". To test it out, open two or more telnet sessions to "localhost 54321", type the same conversation ID string for each, then send messages to yourself.

If you want the program to listen on a different port, edit esprelay.py and change the port number in the main() function. You could also change the host assignment to listen on a specific interface.

The protocol is super-simple:

• Clients send lines of text terminated by '\n' or '\r\n' to the server
• The first line of text sent by the client declares its conversation ID; this can be any string
• Lines after the first line are echoed to other clients that declared the same conversation ID
• Clients can disconnect at any time