Develop Reference

Converting Python Chat Application from using Socket to Websocket

I have been able to successfully create a chat application that works within a local network. I am wanting to deploy the server script to Heroku to enable connections from outside of the local network. Obviously I cannot use sockets on Heroku and will need to convert my code to utilize Websockets instead. I could re-write the entire script but wanting to see if there is a "path of least resistance" using the code I already have.
So the question: Is there a simple way to convert the Code I have to utilize websockets instead of sockets?
Server Side Code
import socket
from threading import Thread
# server's IP address
SERVER_HOST = "54.243.238.66"
SERVER_PORT = 5002 #port we want to use
separator_token = "<SEP>" # use this to separate the client name and message
#initialize list/set of all connected client's sockets
client_sockets = set()
#create a TCP socket
s = socket.socket()
#make the port reuseable
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
#bind the socket to the address we spedified
s.bind((SERVER_HOST, SERVER_PORT))
#listen for upcoming connections
s.listen(5)
print(f"[*] Listening as {SERVER_HOST}:{SERVER_PORT}")
def listen_for_client(cs):
"""
This function keeps listening for a message from 'cs' socket
Whenever a message is received, broadcast it to all other connected clients
"""
while True:
try:
#keep listening for a message from 'cs' socket
msg = cs.recv(1024).decode()
except Exception as e:
#Client no longer connected
#remove client from the set
print(f"[!] Error: {e}")
client_sockets.remove(cs)
else:
#if we received a message, replace the <SEP> token with ": " for nice printing
msg = msg.replace(separator_token, ": ")
for client_socket in client_sockets:
client_socket.send(msg.encode())
while True:
client_socket, client_address = s.accept()
print(f"[+] {client_address} connected.")
client_sockets.add(client_socket)
t = Thread(target=listen_for_client, args=(client_socket,))
t.daemon = True
t.start()
for cs in client_sockets:
cs.close()
s.close()
Client Side Code
import sys
import subprocess
subprocess.check_call([sys.executable, '-m', 'pip', 'install', 'colorama'])
import socket
import random
from threading import Thread
from datetime import datetime
from colorama import Fore, init, Back
init()
colors = [Fore.BLUE, Fore.CYAN, Fore.GREEN, Fore.LIGHTBLACK_EX,
Fore.LIGHTBLUE_EX, Fore.LIGHTCYAN_EX, Fore.LIGHTGREEN_EX,
Fore.LIGHTMAGENTA_EX, Fore.LIGHTRED_EX, Fore.LIGHTWHITE_EX,
Fore.LIGHTYELLOW_EX, Fore.MAGENTA, Fore.RED, Fore.WHITE, Fore.YELLOW
]
client_color = random.choice(colors)
SERVER_HOST = "54.243.238.66"
SERVER_PORT = 5002
separator_token = "<SEP>"
s = socket.socket()
print(f"[*] Connecting to {SERVER_HOST}:{SERVER_PORT}...")
s.connect((SERVER_HOST, SERVER_PORT))
print("[+] Connected.")
name = input("Enter your name: ")
print("To exit, type 'q' at any time and press enter.")
def listen_for_messages():
while True:
message = s.recv(1024).decode()
print("\n" + message)
# make a thread that listens for messages to this client & print them
t = Thread(target=listen_for_messages)
# make the thread daemon so it ends whenever the main thread ends
t.daemon = True
# start the thread
t.start()
while True:
# input message we want to send to the server
to_send = input()
# a way to exit the program
if to_send.lower() == 'q':
break
# add the datetime, name & the color of the sender
date_now = datetime.now().strftime('%Y-%m-%d %H:%M:%S')
to_send = f"{client_color}[{date_now}] {name}{separator_token}{to_send}{Fore.RESET}"
# finally, send the message
s.send(to_send.encode())
# close the socket
s.close()

socket chat room - python 3.7

This is a python chat room that I've been working on and it enables to you to chat to other people on the same network through python
Host:
import socket
import sys
import time
s = socket.socket()
host = socket.gethostname()
port = 8080
s.bind((host,port))
print("")
print("Sever adress is", host)
print("")
name = input(str("Please enter your username : "))
s.listen(1)
print("")
print("Waiting for any incoming connections ... ")
print("")
conn, addr = s.accept()
print("Recieved connection")
#connection done ###
s_name = conn.recv(1024)
s_name = s_name.decode()
print("")
print(s_name, "has connected to the chat room")
print("")
conn.send(name.encode())
## messaging loop ##
while 1:
message = input(str("Please enter enter your message : "))
print("")
conn.send(message.encode())
message = conn.recv(1024)
message = message.decode()
print("")
print(name,": ",message)
print("")
Client:
import socket
import sys
import time
print("Welcome to python chat ")
print("")
print("Initiallsing....")
time.sleep(1)
s = socket.socket()
print("")
host = input(str("Please enter server adress : "))
print("")
name = input(str("Please enter your name : "))
port = 8080
print("")
time.sleep(1)
s.connect((host,port))
print("Connected...")
## Conection done ##
s.send(name.encode())
s_name = s.recv(1024)
s_name = s_name.decode()
print("")
print( s_name, "has joined the chat room ")
while 1:
message = s.recv(1024)
message = message.decode()
print("")
print(name,": ",message)
print("")
message = input(str("Please enter your enter message : "))
print("")
s.send(message.encode())
I have 2 problems, the first problem is that it only allows one person to speak at a time, what I mean by this say that if you send a message first you won't be allowed to send another message until the other person has responded. The second problem is that this code only works for 2 users, I want it so it works for multiple users
Edit:
Also could some one acutually give a proper solution instead of telling me to start all over again please because it took me so long to figure out how to make this system in the place.
Thank you

You need to create two separate threads for sending and receiving. The way you have written the loop will not work for both way communication simultaneously. Because after sending a message the loop is waiting to receive something. [If you want to run the code over internet, replace localhost with the desired IP address in the line HOST = 'localhost'] Let me share a solution (this is a sample solution I have done while TAing an undergraduate class on networking):
I have tested the code on a Linux machine (Ubuntu 18.04). I have got students who have successfully ran this on their Mac. I am not sure if it runs on a windows machine. Even if it does not work on a Windows machine, a few minor modifications should do the trick.
Server sider code (you need to run this first): chatServerDuplex.py
# Import socket module
from socket import *
import threading
import sys # In order to terminate the program
FLAG = False # this is a flag variable for checking quit
# function for receiving message from client
def recv_from_client(conn):
global FLAG
try:
# Receives the request message from the client
while True:
if FLAG == True:
break
message = conn.recv(1024).decode()
# if 'q' is received from the client the server quits
if message == 'q':
conn.send('q'.encode())
print('Closing connection')
conn.close()
FLAG = True
break
print('Client: ' + message)
except:
conn.close()
# function for receiving message from client
def send_to_client(conn):
global FLAG
try:
while True:
if FLAG == True:
break
send_msg = input('')
# the server can provide 'q' as an input if it wish to quit
if send_msg == 'q':
conn.send('q'.encode())
print('Closing connection')
conn.close()
FLAG = True
break
conn.send(send_msg.encode())
except:
conn.close()
# this is main function
def main():
threads = []
global FLAG
# TODO (1) - define HOST name, this would be an IP address or 'localhost' (1 line)
HOST = 'localhost'
# TODO (2) - define PORT number (1 line) (Google, what should be a valid port number)
# make sure the ports are not used for any other application
serverPort = 6789
# Create a TCP server socket
#(AF_INET is used for IPv4 protocols)
#(SOCK_STREAM is used for TCP)
# TODO (3) - CREATE a socket for IPv4 TCP connection (1 line)
serverSocket = socket(AF_INET, SOCK_STREAM)
# Bind the socket to server address and server port
# TODO (4) - bind the socket for HOSR and serverPort (1 line)
serverSocket.bind((HOST, serverPort))
# Listen to at most 1 connection at a time
# TODO (5) - listen and wait for request from client (1 line)
serverSocket.listen(1)
# Server should be up and running and listening to the incoming connections
print('The chat server is ready to connect to a chat client')
# TODO (6) - accept any connection request from a client (1 line)
connectionSocket, addr = serverSocket.accept()
print('Sever is connected with a chat client\n')
t_rcv = threading.Thread(target=recv_from_client, args=(connectionSocket,))
t_send = threading.Thread(target=send_to_client, args=(connectionSocket,))
# call the function to receive message server
#recv_from_server(clientSocket)
threads.append(t_rcv)
threads.append(t_send)
t_rcv.start()
t_send.start()
t_rcv.join()
t_send.join()
# closing serverScoket before exiting
print('EXITING')
serverSocket.close()
#Terminate the program after sending the corresponding data
sys.exit()
# This is where the program starts
if __name__ == '__main__':
main()
Client side code: chatClientDuplex.py
from socket import *
import threading
import sys
FLAG = False # this is a flag variable for checking quit
# function for receiving message from client
def send_to_server(clsock):
global FLAG
while True:
if FLAG == True:
break
send_msg = input('')
clsock.sendall(send_msg.encode())
# function for receiving message from server
def recv_from_server(clsock):
global FLAG
while True:
data = clsock.recv(1024).decode()
if data == 'q':
print('Closing connection')
FLAG = True
break
print('Server: ' + data)
# this is main function
def main():
threads = []
# TODO (1) - define HOST name, this would be an IP address or 'localhost' (1 line)
HOST = 'localhost' # The server's hostname or IP address
# TODO (2) - define PORT number (1 line) (Google, what should be a valid port number)
PORT = 6789 # The port used by the server
# Create a TCP client socket
#(AF_INET is used for IPv4 protocols)
#(SOCK_STREAM is used for TCP)
# TODO (3) - CREATE a socket for IPv4 TCP connection (1 line)
clientSocket = socket(AF_INET, SOCK_STREAM)
# request to connect sent to server defined by HOST and PORT
# TODO (4) - request a connection to the server (1 line)
clientSocket.connect((HOST, PORT))
print('Client is connected to a chat sever!\n')
# call the function to send message to server
#send_to_server(clientSocket)
t_send = threading.Thread(target=send_to_server, args=(clientSocket,))
# call the function to receive message server
#recv_from_server(clientSocket)
t_rcv = threading.Thread(target=recv_from_server, args=(clientSocket,))
threads.append(t_send)
threads.append(t_rcv)
t_send.start()
t_rcv.start()
t_send.join()
t_rcv.join()
print('EXITING')
sys.exit()
# This is where the program starts
if __name__ == '__main__':
main()

Your first problem is likely due to the fact that python sockets are blocking by default.
What this means is that, for example, on the line message = s.recv(1024), your program will keep listening and won't move on to the rest of your script until it receives something.
If you want two people to be able to receive and send at the same time, you might want to look into non-blocking sockets and some asynchronous programming.
This how-to from the official documentation might help you: https://docs.python.org/2/howto/sockets.html#non-blocking-sockets

System123456 the problem is that you built a client-server system when the server listens and the client connects to it. Try looking at peer-to-peer systems instead where each node is an equal. For building a chat room you might review DHT nodes.

Send messages received by server to multiple clients in python 2.7 with socket programming

So I have created a socket program for both client and server as a basic chat. I made it so the server accepts multiple clients with threading, so that is not the problem. I am having trouble sending messages to each client that is connected to the server. I am not trying to have the server send a message it created but rather have client1 sending a message to client2 by going through the server. For some reason it will only send it back to client1.
For example, client1 will say hello and the server will send the same message back to client1 but nothing to client2. I fixed this slightly by making sure the client doesn't receive its own message but client2 is still not receiving the message from the client1.
Any help will be appreciated.
I have tried multiple changes and nothing seems to work. You can look at my code for specifics on how I did things but ask if there are any questions.
Also, there is a question where someone has asked that is similar and I thought it would give me an answer but the responses stopped going through and a solution was never fully given, so please don't just refer me to that question. that is located here: Python 3: Socket server send to multiple clients with sendto() function.
Here's the code:
CLIENT:
import socket
import sys
import thread
#Create a socket
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
#Enter username to identify self to others
name = raw_input("Enter username: ") + ": "
#Connect socket to ip and port
host = socket.gethostname()
#host = '192.168.1.10'
server_address = (host, 4441)
sock.connect(server_address)
#function waiting to receive and print a message
def receive(nothing):
while True:
data = sock.recv(1024)
if message != data:
print data
# Send messages
while True:
#arbitrary variable allowing us to have a thread
nothing = (0, 1)
message = name + raw_input("> ")
sock.sendall(message)
#thread to receive a message
thread.start_new_thread(receive, (nothing,))
SERVER:
import socket
import sys
import thread
# Create a TCP/IP socket
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# Bind the socket to the port
host = socket.gethostname()
server_address = (host, 4441)
sock.bind(server_address)
#Listen for incoming connections
sock.listen(5)
print "Waiting for connection..."
#Variable for the number of connections
numbOfConn = 0
#Name of list used for connections
addressList = []
#Function that continuosly searches for connections
def clients(connection, addressList):
while True:
message = connection.recv(1024)
print message
#connection.sendall(message)
#for loop to send message to each
for i in range(0,numbOfConn - 1):
connection.sendto(message, addressList[i])
connection.close()
while True:
#accept a connection
connection, address = sock.accept()
print 'Got connection from', address
numbOfConn += 1
addressList.append((address))
#Thread that calls the function: clients and stores them in a tuple called connection
thread.start_new_thread(clients, (connection, addressList))
sock.close()
Please help me if you can!
EDIT:
I was able to fix it to a certain extent. It is still a little buggy but I am able to send messages back and forth now. I needed to specify the connection socket as well as the address. Here's the updated code:
SERVER
import socket
import sys
import thread
# Create a TCP/IP socket
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# Bind the socket to the port
host = socket.gethostname()
server_address = (host, 4441)
sock.bind(server_address)
#Listen for incoming connections
sock.listen(5)
print "Waiting for connection..."
#Variable for the number of connections
numbOfConn = 0
#Name of list used for connections
addressList = []
connectionList = []
#Function that continuosly searches for connections
def clients(connectionList, addressList):
while True:
for j in range(0,numbOfConn):
message = connectionList[j].recv(1024)
print message
#for loop to send message to each
for i in range(0,numbOfConn):
connectionList[i].sendto(message, addressList[i])
connection.close()
while True:
#accept a connection
connection, address = sock.accept()
print 'Got connection from', address
numbOfConn += 1
addressList.append((address))
connectionList.append((connection))
#Thread that calls the function: clients and stores them in a tuple called connection
thread.start_new_thread(clients, (connectionList, addressList))
sock.close()

How can I know the number of clients connected to the server and return the number of the connected clients to the user?

I want to know these for I am getting crazy with this:
How can I do these:
1-If the server terminates the clients should terminate also. Your server should allow the administrator to close all connections (i.e. the server must wait for the user to terminate the program preferably through a menu interface)
2-In order to know the number of clients connected you will need to identify each client uniquely – this can be accomplished by using the pid that is uniquely assigned for each client connection (store these in a global list). These connections can change dynamically (i.e. clients can disconnect and reconnect) so you must maintain this list on the server.
This is my server side code:
Thanks in advance
import _thread
import socket
import sys
from datetime import datetime
def serveclient(c):
global v, nclient, vlock, nclientlock
while(True):
k=(c.recv(1)).decode('utf-8')
if(k==''):
break
if(k=='D'):
today = str(datetime.now().strftime('%Y-%m-%d'))
c.send(today.encode('utf-8'))
if(k=='T'):
tme = str(datetime.now().strftime('%H:%M:%S'))
c.send(tme.encode('utf-8'))
if(k=='X'):
<<<< # Here I should put the number of clients connected and echo back the number like the above code
vlock.acquire()
v+=k
vlock.release()
#Echo back
c.send(v.encode('utf-8'))
c.close() #End connection
nclientlock.acquire()
nclient-=1
nclientlock.release()
#Main driver code
listener = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
port = int(sys.argv[1])
listener.bind(('',port))
listener.listen(5)
#Initialize global data
v=''
vlock=_thread.allocate_lock()
nclient=10 #Max number of clients
nclientlock=_thread.allocate_lock()
#accept calls from clients
for i in range(nclient):
(client, ap) = listener.accept()
_thread.start_new_thread(serveclient, (client,))
listener.close()
while nclient >0:
pass #do nothing, just wait for client count to drop to zero
print('The final string is: ', v)
<<<<<<<<<<<<<<<<<<<<<<<<<This the Client Code>>>>>>>>>>>>>>>>>>>>>>>
#Client Program. Sends a single char at a time to the server until the client
#sends a '', this will terminate the client.
#
#usage: python server port
import socket
import sys
#create the socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
host = sys.argv[1] #Server info from cmd line
port = int(sys.argv[2]) #Port from cmd line
#Conncet to server
s.connect((host, port))
while(True):
#get letter
k = input('enter a letter: ')
s.send(k.encode('utf-8'))
if(k==''):
break
v=s.recv(1024) #receive upto 1024 bytes
print(v.decode('utf-8'))
s.close()

Just increment a count every time you accept a socket, and decrement it every time you close an accepted socket.

socket.send working only once in python code for an echo client

I have the following code for an echo client that sends data to an echo server using socket connection:
echo_client.py
import socket
host = '192.168.2.2'
port = 50000
size = 1024
def get_command():
#..Code for this here
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((host,port))
while 1:
msg = get_command()
if msg == 'turn on':
s.send('Y')
elif msg == 'turn off':
s.send('N')
elif msg == 'bye bye':
break
else:
s.send('X')
data = s.recv(size)
print 'Received: ',data
s.close()
echo_server.py
import socket
host = ''
port = 50000
backlog = 5
size = 1024
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((host,port))
s.listen(backlog)
while 1:
client, address = s.accept()
data = client.recv(size)
if data:
client.send(data)
client.close()
The problem im facing is that in the client s.send works only the first time even though its in an infinite loop. The client crashes with connection timed out, some time after the first send/receive has completed.
Why is s.send working only once ?. How can i fix this in my code ?
Please Help
Thank You

Your server code only calls recv once. You should call accept once if you only want to receive one connection, but then you need to loop calling recv and send.

Your problem is that you are blocking on the accept inside the server's loop.
This is expecting the server to accept connections from more than one client. If you want that, and for each client to send multiple commands, you would need to spawn a new thread (or process) after the accept, with a new while loop (for client communication) in that thread/process.
To fix your example to work with just one client, you need to move the accept outside the loop, like so:
client, address = s.accept()
while 1:
data = client.recv(size)
if data:
client.send(data)