catching a broken socket in python

Question

I'm having problems detecting a broken socket when a broken pipe exception occurs. See the below code for an example:

The Server:

import errno, select, socket, time, SocketServer

class MetaServer(object):
    def __init__(self):
        self.server = Server(None, Handler, bind_and_activate=False)
    def run(self, sock, addr):
        rfile = sock.makefile('rb', 1)
        self.server.process_request(sock, addr)
        while 1:
            r, _, _ = select.select([rfile], [], [], 1.0)
            if r:
                print 'Got %s' % rfile.readline()
            else:
                print 'nothing to read'

class Server(SocketServer.ThreadingMixIn, SocketServer.TCPServer):
    allow_reuse_address = True
    daemon_threads = True

class Handler(SocketServer.StreamRequestHandler):
    def handle(self):
        print 'connected!'
        try:
            while 1:
                self.wfile.write('testing...')
                time.sleep(1)
        except socket.error as e:
            if e.errno == errno.EPIPE:
                print 'Broken pipe!'
        self.finish()
        self.request.close()

if __name__ == '__main__':
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.bind(('127.0.0.1', 8081))
    s.listen(5)
    ms = MetaServer()
    while 1:
        client, address = s.accept()
        ms.run(client, address)

The Client:

import select, socket

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect(('127.0.0.1', 8081))
while 1:
    r, _, _ = select.select([s], [], [], 1.0)
    if not r:
        continue
    msg = s.recv(1024)
    print 'Got %s' % (msg,)

Now, if I run the server and client, all is well, and I get a "nothing is read" message every second. As soon as I CTRL-C out of the client, the server goes crazy and starts to "read" from what should be a busted socket, dumping a lot of "Got " messages.

Is there some way to detect this broken socket in the MetaServer.run() function to avoid the above said behavior?

Answer 1

Yes, that's something which is not really in the documentation but old Un*x behavior: You need to abort when you get an empty string.