def broadcast(message, connection, list_of_clients):
for clients in list_of_clients:
if clients != connection: # Make sure it's not sending to itself
try:
chatlib.write_msg(clients, message, MAXBUFFERSIZE)
except: # Can't send?
clients.close()
# If the link is broken, we remove the client
remove(clients, list_of_clients)
def clientthread(conn, addr, clientNicknames, list_of_clients, end_event,
threadStream):
# Nickname collection
while end_event.is_set():
dateTime = datetime.now()
uniqueName = True
nickname = ""
message = chatlib.read_msg(conn, MAXBUFFERSIZE)
nickname = message.rstrip() # Get rid of the newline
if nickname == "BYE": # In case the client disconnects before making a nickname
threadStream[0] = str(dateTime) + ", " + str(
addr) + " Left before creating a nickname\n"
remove(conn, list_of_clients)
return
if re.match(
"^[a-zA-Z0-9]{2,30}$", nickname
): # Ensure the nickname is alphanumeric, no spaces allowed
for name in clientNicknames: # Ensure the nickname is unique
if name == nickname:
uniqueName = False
if uniqueName:
chatlib.write_msg(conn, "READY", MAXBUFFERSIZE)
clientNicknames.append(nickname)
threadStream[0] = str(dateTime) + ", " + str(
addr) + ", " + nickname + " connected.\n"
message_to_send = "<" + nickname + ">" " joined the chatroom.\n"
broadcast(message_to_send, conn, list_of_clients)
break
else:
chatlib.write_msg(conn, "RETRY", MAXBUFFERSIZE)
else:
chatlib.write_msg(conn, "INVALID", MAXBUFFERSIZE)
# Start waiting for regular messages
while end_event.is_set():
try:
message = chatlib.read_msg(conn, MAXBUFFERSIZE)
message = message.rstrip() # Strip newlines
if message == "BYE": # If client disconnects
message_to_send = "<" + nickname + ">" " left the chatroom.\n"
threadStream[0] = str(dateTime) + ", " + str(
addr) + ", " + nickname + " disconnected.\n"
broadcast(message_to_send, conn,
list_of_clients) # Let everyone know
clientNicknames.remove(
nickname) # Remove from list of nicknames
remove(conn, list_of_clients) # Remove the connection
break
elif message:
threadStream[0] = nickname + ": " + message + "\n"
# Calls broadcast function to send message to all
message_to_send = "<" + nickname + "> " + message
broadcast(message_to_send, conn, list_of_clients)
else:
# If the message is empty or broken remove the connection
remove(conn, list_of_clients)
except:
continue
return
def main():
# Creates a TCP socket
server = chatlib.socket_create()
try:
server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
server.setblocking(0)
except socket.error as err:
print("Socket error: %s" % err)
exit()
# Create an event to signal subthreads to end
end_event = threading.Event()
end_event.set()
# Checks whether sufficient arguments have been provided
if (len(sys.argv) != 2) and (len(sys.argv) != 3):
print "Correct usage: script, IP address, (optional) port number"
exit()
IP_address = str(sys.argv[1])
# Takes second argument from command prompt as port number
if len(sys.argv) == 3:
Port = int(sys.argv[2])
else:
# Default port
Port = 8888
# Binds the server to an entered IP address and at the
# Specified port number.
try:
server.bind((IP_address, Port))
server.listen(100)
except socket.error as err:
print("Socket error: %s" % err)
exit()
list_of_clients = []
clientNicknames = []
threads = []
print("Server started successfully...")
threadStream = [" "]
while True:
if threadStream[0] != " ":
log(threadStream[0])
threadStream[0] = " "
try:
# Get socket conn and address from client
try:
conn, addr = server.accept()
#add conn to list of connections
list_of_clients.append(conn)
chatlib.write_msg(conn, "HELLO", MAXBUFFERSIZE)
try:
t = threading.Thread(target=clientthread,
args=(conn, addr, clientNicknames,
list_of_clients, end_event,
threadStream))
threads.append(t)
t.start()
except Exception as e:
print("Error starting thread: ", e)
except socket.error as err:
# Catches errno11 because accept is no longer a blocking call
if err.errno == 11:
pass
else:
print("Socket error: %s" % err)
except KeyboardInterrupt: # Close server
message = "SERVER CLOSING IN 5 SECONDS"
print("\n" + message)
broadcast(message, server, list_of_clients)
time.sleep(
5) # Give time for clients to see server closing warning
message = "SERVER CLOSED"
broadcast(message, server, list_of_clients)
end_event.clear(
) # Trigger the event so that the subthreads end their while loops
for t in threads:
t.join()
for conns in list_of_clients:
conns.close()
server.close()
return
def setNickname():
nickname = sys.stdin.readline()
chatlib.write_msg(server, nickname, MAXBUFFERSIZE)
sys.stdout.flush()
print ("You may now talk in the chatroom. You may exit at anytime by using Ctrl + c.")
nickSet = True
elif message == "RETRY":
print("That nickname is already in use. Try again.")
nickSet = "RETRY"
elif message == "INVALID":
print("Nickname must be alphanumberic and 2-30 Characters. Try again.")
nickSet = "INVALID"
else:
print message
# Sends a nick name to the server
elif nickSet == "INIT" or nickSet == "RETRY" or nickSet == "INVALID" :
setNickname()
nickSet = ""
# If the client has a nickname then they can send messages
elif nickSet == True:
message = sys.stdin.readline()
chatlib.write_msg(server, message, MAXBUFFERSIZE)
sys.stdout.write("<You> ")
sys.stdout.write(message)
sys.stdout.flush()
except KeyboardInterrupt:
# Tells the server that the client is disconnecting
chatlib.write_msg(server, "BYE", MAXBUFFERSIZE)
break
sys.stdout.flush()
server.close()
exit()