Python Socket Programming in 10 Simple Steps (with Multi-Client Support)

This guide walks you through building a simple Python socket server that can handle multiple clients at once, along with a basic client script. Follow these 10 steps to understand the essentials of network programming in Python.

1. Import Required Modules

`import socket
import threading
`

1. Define a Function to Handle Each Client

`def handle_client(conn, addr):
print(f"Connected by {addr}")
data = conn.recv(1024)
if data:
print(f"Received from {addr}: {data.decode()}")
conn.sendall(b"Hello from server!")
conn.close()
`

1. Set Server Address and Port

`HOST = '127.0.0.1'
PORT = 5555
`

1. Create a Socket

`with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
`

1. Bind the Socket

`    s.bind((HOST, PORT))
`

1. Start Listening for Connections

`    s.listen()
print("Server listening...")
`

1. Accept Clients in a Loop

`    while True:
conn, addr = s.accept()
`

1. Start a New Thread for Each Client

`        thread = threading.Thread(target=handle_client, args=(conn, addr))
thread.start()
`

1. Write the Client Code

`import socket

HOST = '127.0.0.1'
PORT = 5555

with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
s.connect((HOST, PORT))
s.sendall(b"Hello from client!")
data = s.recv(1024)
print(f"Received from server: {data.decode()}")
`

1. Run and Test

• Start the server: python server.py

• Run client.py in one or more terminals.

• Each client will connect, send a message, and receive a response.

• The server will handle all clients simultaneously!