Python chat client & Server sockets issue

Question

I'm sort of new to python and this is the first time I'm using sockets, I am trying to make an application that has a client and server, A user can type into the client and it will be sent to the server which then sends it to all the other clients. I have it to a working state but whenever I try to send a second message I always get an error 'error: [Errno 10058] A request to send or receive data was disallowed because the socket had already been shut down in that direction with a previous shutdown call'. How can I make this work?

Tried adding a socket shutdown and close before going starting a new socket or sending a new message, Tried just using the existing socket again and neither work giving me No error but the program just hangs while sending to the server.

Server

import socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

def __init__():
    HOST = '0.0.0.0'    
    PORT = 50012
    print("Initialising..")
    print("Initialized.")
    print("Binding..")
    s.bind((HOST, PORT))
    print("Bound.")
    print("Listener started")

    __listen__(HOST, PORT)


def __broadcast__(list_clients, conn, addr, HOST, PORT):
    print("broadcasting")
    while 1:
        data = conn.recv(1024)
        if not data: break
        print "{} Recieved from {}".format(data, addr)
        for x in list_clients:
            conn.sendto(data, x)
            __listen__(HOST, PORT)


def __listen__(HOST, PORT):
    print("listening")
    s.listen(1)
    conn, addr = s.accept()
    list_clients=[]
    list_clients.append(addr)
    print 'Connected by', addr
    __broadcast__(list_clients, conn, addr, HOST, PORT)


def ext():
    conn.close()

def __main__():
    print("Initialising..")
    __init__()
    print("Initialized.")
    print("Listener starting..")
    __listen__()

__init__()

Client

import socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)

def __init__():
    HOST = '127.0.0.1'
    PORT =  50012
    __connect__(HOST, PORT)

def __connect__(HOST, PORT):
    s.connect((HOST, PORT))
    __sendmessage__(HOST, PORT)

def __sendmessage__(HOST, PORT):
    s.sendall(raw_input("You $: "))
    while 1:
        data = s.recv(1024)
        print data
        __sendmessage__(HOST, PORT)

def __exit__():
    s.shutdown(0)
__init__()

score 0 · Answer 1 · answered Sep 17 '19 at 14:28

Your server calls __listen__() and thereby accept() recursively each time after it did sendto() a client, i. e. it waits for a new connection after each message sent - that cannot work. The server has to wait simultaneously for connections and data from clients; this is easy with select.select(). Replace your __init__(), __broadcast__() and __listen__() with

    from select import select
    HOST = '0.0.0.0'    
    PORT = 50012
    s.bind((HOST, PORT))
    s.listen(1)
    list_clients = []
    for reads in iter(lambda: select([s]+list_clients, [], [])[0], []):
        for ready in reads: # each time select reports something is ready
            if s == ready:  # accept new client if it's the server socket
                conn, addr = s.accept()
                list_clients.append(conn)   # store the connection socket
                print 'connected by', addr
            else:           # data from a client
                try: data = ready.recv(1024)
                except socket.error: data = ''
                if not data:                # client disconnected, remove
                    list_clients.remove(ready)
                    ready.close()
                    continue
                print "{} received from {}".format(data, ready.getpeername())
                print("broadcasting")
                for x in list_clients: x.send(data)

The client has a similar problem of not simultaneously waiting for socket and terminal input. For a working client implementation, see this answer to Handle multiple requests with select.

Python chat client & Server sockets issue

1 Answers1