Python -Chat -Anwendung
# Python program to implement server side of chat room.
import socket
import select
import sys
'''Replace "thread" with "_thread" for python 3'''
from thread import *
"""The first argument AF_INET is the address domain of the
socket. This is used when we have an Internet Domain with
any two hosts The second argument is the type of socket.
SOCK_STREAM means that data or characters are read in
a continuous flow."""
server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
# checks whether sufficient arguments have been provided
if len(sys.argv) != 3:
print ("Correct usage: script, IP address, port number")
exit()
# takes the first argument from command prompt as IP address
IP_address = str(sys.argv[1])
# takes second argument from command prompt as port number
Port = int(sys.argv[2])
"""
binds the server to an entered IP address and at the
specified port number.
The client must be aware of these parameters
"""
server.bind((IP_address, Port))
"""
listens for 100 active connections. This number can be
increased as per convenience.
"""
server.listen(100)
list_of_clients = []
def clientthread(conn, addr):
# sends a message to the client whose user object is conn
conn.send("Welcome to this chatroom!")
while True:
try:
message = conn.recv(2048)
if message:
"""prints the message and address of the
user who just sent the message on the server
terminal"""
print ("<" + addr[0] + "> " + message)
# Calls broadcast function to send message to all
message_to_send = "<" + addr[0] + "> " + message
broadcast(message_to_send, conn)
else:
"""message may have no content if the connection
is broken, in this case we remove the connection"""
remove(conn)
except:
continue
"""Using the below function, we broadcast the message to all
clients who's object is not the same as the one sending
the message """
def broadcast(message, connection):
for clients in list_of_clients:
if clients!=connection:
try:
clients.send(message)
except:
clients.close()
# if the link is broken, we remove the client
remove(clients)
"""The following function simply removes the object
from the list that was created at the beginning of
the program"""
def remove(connection):
if connection in list_of_clients:
list_of_clients.remove(connection)
while True:
"""Accepts a connection request and stores two parameters,
conn which is a socket object for that user, and addr
which contains the IP address of the client that just
connected"""
conn, addr = server.accept()
"""Maintains a list of clients for ease of broadcasting
a message to all available people in the chatroom"""
list_of_clients.append(conn)
# prints the address of the user that just connected
print (addr[0] + " connected")
# creates and individual thread for every user
# that connects
start_new_thread(clientthread,(conn,addr))
conn.close()
server.close()
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