This program has both the ChatServer class and ChatClient class in the same file, and should be called in the terminal by --name=server --port=8800 for the server and --name=client1 --port=8800 for the client. The problem comes from the client class not being able to complete a try:
When running the program with server name, it seems to work fine. When it runs with client name, I get the output Failed to connect to chat server @ port 8800.
You can find where this except statement lies.
import select
import socket
import sys
import signal
import _pickle as cPickle
import struct
import argparse
SERVER_HOST = 'localhost'
CHAT_SERVER_NAME = 'server'
# Some utilities
def send(channel, *args):
buffer = cPickle.dumps(args)
value = socket.htonl(len(buffer))
size = struct.pack("L", value)
channel.send(size)
channel.send(buffer)
def receive(channel):
size = struct.calcsize("L")
size = channel.recv(size)
try:
size = socket.ntohl(struct.unpack("L", size)[0])
except struct.error as e:
return ''
buf = ""
while len(buf) < size:
buf = channel.recv(size - len(buf))
return cPickle.loads(buf)[0]
class ChatServer(object):
def __init__(self, port, backlog=5):
self.clients = 0
self.clientmap = {}
self.outputs = []
self.server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# Enable re-using socket address
self.server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
self.server.bind((SERVER_HOST, port))
print('Server listening to port: %s...' % port)
self.server.listen(backlog)
# Catch keyboard interrupts
signal.signal(signal.SIGINT, self.sighandler)
def sighandler(self, signum, frame):
# Close the server
print("Shutting down server...")
# Close existing client sockets
for output in self.outputs:
output.close()
self.server.close()
def get_client_name(self,client):
info = self.clientmap[client]
host, name = info[0][0], info[1]
return '@'.join((name, host))
def run(self):
inputs = [self.server, sys.stdin]
self.outputs = []
running = True
while running:
try:
readable, writeable, exceptional = select.select(inputs, self.outputs, [])
except select.error as e:
break
for sock in readable:
if sock == self.server:
# handle the server socket
client, address = self.server.accept()
print("Chat Server: got connection %d from %s" % (client.fileno(), address))
# Read the login name
cname = receive(client).split('NAME: ')[1]
# Compute client name ad send back
self.clients += 1
send(client, 'CLIENT: ' + str(address[0]))
inputs.append(client)
self.clientmap[client] = (address, cname)
# Send joining information to other clients
msg = "\n(Connected: New client (%d) from %s)" % (self.clients, self.get_client_name(client))
for output in self.outputs:
send(output, msg)
self.outputs.append(client)
elif sock == sys.stdin:
# Handle standard input
junk = sys.stdin.readline()
running = False
else:
# Handle all other sockets
try:
data = receive(sock)
if data:
# Send as new client's message..
msg = '\n[' + self.get_client_name(sock) + ']>>' + data
# Send data to all except ourself
for output in self.outputs:
if output != sock:
send(output, msg)
else:
print("Chat server: %d hung up" % sock.fileno())
self.clients -= 1
sock.close()
inputs.remove(sock)
self.outputs.remove(sock)
# Sending client leaving info to others
msg = "\n(Now hung up: Client from %s" % self.get_client_name(sock)
for output in self.outputs:
send(output, msg)
except socket.error as e:
# Remove
inputs.remove(sock)
self.outputs.remove(sock)
self.server.close()
class ChatClient(object):
def __init__(self, name, port, host=SERVER_HOST):
self.name = name
self.connected = False
self.host = host
self.port = port
# Initial Prompt
self.prompt = '[' + '@'.join((name, socket.gethostname().split('.')[0])) + ']> '
# Connect to server at port
try:
self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self.sock.connect((host, self.port))
print("Now connected to chat server@ port %d" % self.port)
self.connected = True
# Send by name...
send(self.sock, 'NAME: ' + self.name)
data = receive(self.sock)
# Contains client address, set it
addr = data.split('CLIENT: ')[1]
self.prompt = '[' + '@'.join((self.name, addr)) + ']>'
except socket.error as e:
print("Failed to connect to chat server @ port %d" % self.port)
sys.exit(1)
def run(self):
while self.connected:
try:
sys.stdout.write(self.prompt)
sys.stdout.flush()
# Wait for input from stdin and socket
readable, writable, exceptional = select.select([0, self.sock], [], [])
for sock in readable:
if sock == 0:
data = sys.stdin.readline().strip()
if data:
send(self.sock, data)
elif sock == self.sock:
data = receive(self.sock)
if not data:
print('Client shutting down')
self.connected = False
break
else:
sys.stdout.write(data + '\n')
sys.stdout.flush()
except KeyboardInterrupt:
print("Client interrupted")
self.sock.close()
break
if __name__ == "__main__":
parser = argparse.ArgumentParser(description='Socket Server Example with Select')
parser.add_argument('--name', action="store", dest="name", required=True)
parser.add_argument('--port', action="store", dest="port", type=int, required=True)
given_args = parser.parse_args()
port = given_args.port
name = given_args.name
if name == CHAT_SERVER_NAME:
server = ChatServer(port)
server.run()
else:
client = ChatClient(name=name, port=port)
client.run()
