Server Loop Using Python Sockets and Threading module

Question

I am making server-client communication in python using sockets and threading module. I connect client to server, send some data, receive some data, but the problem is, I can send only two messages. After those, the server is not reciving my packets. Can someone tell me what's wrong? Thanks in advance.

Server.py:

import socket
from threading import Thread
class Server:
 def __init__(self):
 self.host = '127.0.0.1'
 self.port = 9999
 self.server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
 self.server.bind((self.host, self.port))
 self.server.listen(5)
 self.threads = []
 self.listen_for_clients()
 def listen_for_clients(self):
 print('Listening...')
 while True:
 client, addr = self.server.accept()
 print('Accepted Connection from: '+str(addr[0])+':'+str(addr[1]))
 self.threads.append(Thread(target=self.handle_client, args=(client, addr)))
 for thread in self.threads:
 thread.start()
 def handle_client(self, client_socket, address):
 client_socket.send('Welcome to server'.encode())
 size = 1024
 while True:
 message = client_socket.recv(size)
 if message.decode() == 'q^':
 print('Received request for exit from: '+str(address[0])+':'+str(address[1]))
 break
 else:
 print('Received: '+message.decode()+' from: '+str(address[0])+':'+str(address[1]))
 client_socket.send('Received request for exit. Deleted from server threads'.encode())
 client_socket.close()
if __name__=="__main__":
 main = Server()

Client.py

import socket
import sys, time
def main():
 target_host = '127.0.0.1'
 target_port = 9999
 try:
 client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
 except socket.error:
 print('Could not create a socket')
 time.sleep(1)
 sys.exit()
 try:
 client.connect((target_host, target_port))
 except socket.error:
 print('Could not connect to server')
 time.sleep(1)
 sys.exit()
 while True:
 data = input()
 client.send(data.encode())
 message = client.recv(4096)
 print('[+] Received: '+ message.decode())
main()

• Elis Byberi: for thread in self.threads: does start threads in self.threads every time server does get a connection from a client. It is not what you want.
• xaav: Use this: Thread(target=self.handle_client, args=(client, addr)).start().
• Frank Cold: @xaav I used it eariel, hoped that for loop can change something.

Answer 1

You have to send exit message 'q^' to client too to close client.

Warning: Using Unicode as encoding for string is not recommended in socket. A partial Unicode character may be received in server/client resulting in UnicodeDecodeError being raised.

Code for server using threads is:

server.py:

import socket
from threading import Thread
class Server:
 def __init__(self, host, port):
 self.host = host
 self.port = port
 self.server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
 self.server.bind((self.host, self.port))
 self.server.listen(5)
 def listen_for_clients(self):
 print('Listening...')
 while True:
 client, addr = self.server.accept()
 print(
 'Accepted Connection from: ' + str(addr[0]) + ':' + str(addr[1])
 )
 Thread(target=self.handle_client, args=(client, addr)).start()
 def handle_client(self, client_socket, address):
 size = 1024
 while True:
 try:
 data = client_socket.recv(size)
 if 'q^' in data.decode(): 
 print('Received request for exit from: ' + str(
 address[0]) + ':' + str(address[1]))
 break
 else:
 # send getting after receiving from client
 client_socket.sendall('Welcome to server'.encode())
 print('Received: ' + data.decode() + ' from: ' + str(
 address[0]) + ':' + str(address[1]))
 except socket.error:
 client_socket.close()
 return False
 client_socket.sendall(
 'Received request for exit. Deleted from server threads'.encode()
 )
 # send quit message to client too
 client_socket.sendall(
 'q^'.encode()
 )
 client_socket.close()
if __name__ == "__main__":
 host = '127.0.0.1'
 port = 9999
 main = Server(host, port)
 # start listening for clients
 main.listen_for_clients()

client.py:

import socket
import sys, time
def main():
 target_host = '127.0.0.1'
 target_port = 9999
 try:
 client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
 except socket.error:
 print('Could not create a socket')
 time.sleep(1)
 sys.exit()
 try:
 client.connect((target_host, target_port))
 except socket.error:
 print('Could not connect to server')
 time.sleep(1)
 sys.exit()
 online = True
 while online:
 data = input()
 client.sendall(data.encode())
 while True:
 message = client.recv(4096)
 if 'q^' in message.decode():
 client.close()
 online = False
 break
 print('[+] Received: ' + message.decode())
 break # stop receiving
# start client
main()