`socket`

The Python socket module provides a low-level networking interface that allows you to create and use sockets for network communication.

It enables Python programs to connect to other computers over a network, send and receive data, and handle network-related tasks like client-server communication.

Here’s a quick example:

Python
      
>>> import socket

>>> with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
...     s.connect(("www.example.com", 80))
...

Key Features

Creates TCP/IP and UDP sockets
Supports both IPv4 and IPv6 addresses
Provides functions for both synchronous and asynchronous network communication
Offers high-level interfaces for creating server and client applications

Frequently Used Classes and Functions

Object	Type	Description
`socket.socket()`	Class	Represents a network socket
`socket.gethostbyname()`	Function	Resolves a hostname to an IP address
`socket.bind()`	Method	Binds a socket to a local address
`socket.listen()`	Method	Enables a socket to accept incoming connections
`socket.accept()`	Method	Accepts a connection from a client
`socket.recv()`	Method	Receives data from a connected socket
`socket.send()`	Method	Sends data to a connected socket
`socket.close()`	Method	Closes the socket

Examples

Creating a TCP/IP socket:

Python
      
>>> import socket
>>> s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

Connecting to a server:

Python
      
>>> s.connect(("www.example.com", 80))

Common Use Cases

Creating client-server applications
Implementing network protocols
Sending and receiving data over TCP/IP and UDP
Building web servers or clients
Developing chat applications

Real-World Example

Here’s how to create a TCP server that listens for incoming connections and sends a welcome message to the client:

Pythonserver.py
      
    
import socket
import threading

def handle_client(conn, addr):
    with conn:
        print(f"Connected by {addr}")
        conn.sendall(b"Welcome to the server!")

def main():
    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
        s.bind(("localhost", 12345))
        s.listen()
        print("Server listening on port 12345...")
        while True:
            conn, addr = s.accept()
            thread = threading.Thread(
                target=handle_client, args=(conn, addr), daemon=True
            )
            thread.start()

if __name__ == "__main__":
    main()

In this example, you use the socket module to create a server that listens on a specified port and sends a welcome message to each client that connects. To try it out, run the script on your computer. You’ll get a message telling you that the server is listening on port 12345. Then, run the following command:

Shell
      
$ nc localhost 12345
Welcome to the server!

Tutorial

Socket Programming in Python (Guide)

In this in-depth tutorial, you'll learn how to build a socket server and client with Python. By the end of this tutorial, you'll understand how to use the main functions and methods in Python's socket module to write your own networked client-server applications.

advanced python web-dev

For additional information on related topics, take a look at the following resources: