Reading all waiting lines in a SocketServer handler

Question

This is a simple socketserver example that should receive a line over UDP and echo it out:

import socketserver

class LineHandler(socketserver.DatagramRequestHandler):
    def handle(self):
        line = self.rfile.readline().strip()
        print(line)

server = socketserver.UDPServer(('', 4444), LineHandler)
server.serve_forever()

However if two lines come in at the same time, only the first line is read:

(printf 'lol\n'; printf 'what\n') | nc -u localhost 4444

score 1 · Accepted Answer · answered Jan 19 '20 at 01:37

The documentation kind of suggests that readline() will repeatedly call recv() until it gets a newline, which would leave the next line in the socket's buffer and lead to handle() being invoked again. But this doesn't appear to be the case.

Instead, you can use:

for line in self.rfile:
    line = line.strip()
    print(line)

Reading all waiting lines in a SocketServer handler

1 Answers1