LPR client

lpr_client.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import socket
import select

class RSerialError(IOError):
    pass


class RSerial(object):
    def __init__(self):
        self.connect()

    def connect(self):
        self.conn = socket.socket()
        udp = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        udp.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, True)
        udp.sendto("gimme your address, please", ("255.255.255.255", 1235))

        if not select.select([udp], [], [], 1):
            raise RSerialError("couldn't discover the server address.")

        _, addr_and_port = udp.recvfrom(2048)

        addr = addr_and_port[0]

        self.conn.connect((addr, 9100))

    def write(self, data):
        try:
            self.conn.send(data)
        except socket.error, e:
            self.connect()
            self.write(data)

    def __del__(self):
        self.conn.close()