Networking

Socket Programming

The socket module provides low-level networking interfaces. Sockets are endpoints for sending and receiving data across a network.

TCP Server

import socket

server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.bind(("127.0.0.1", 8080))
server.listen(5)
print("Server listening on port 8080...")

while True:
    client, addr = server.accept()
    print(f"Connected by {addr}")
    client.send(b"Hello from server!")
    client.close()

TCP Client

import socket

client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
client.connect(("127.0.0.1", 8080))
data = client.recv(1024)
print(f"Received: {data.decode()}")
client.close()

HTTP Requests with urllib.request

from urllib.request import urlopen

with urlopen("https://api.github.com") as response:
    data = response.read()
    print(response.status)
    print(data[:200])

The requests Library

The requests library simplifies HTTP requests significantly compared to the built-in urllib.

import requests

# GET request
response = requests.get("https://api.github.com/users/python")
print(response.status_code)
print(response.json()["login"])

# POST request with JSON
payload = {"title": "Hello", "body": "World"}
r = requests.post("https://jsonplaceholder.typicode.com/posts", json=payload)
print(r.status_code, r.json())

Handling HTTP Responses

response = requests.get("https://httpbin.org/get", params={"key": "value"})
print(response.text)        # Raw text
print(response.json())      # Parsed JSON
print(response.headers)     # Response headers
print(response.elapsed)     # Request duration

Error Handling in Network Requests

import requests
from requests.exceptions import RequestException

try:
    r = requests.get("https://example.com", timeout=5)
    r.raise_for_status()
except RequestException as e:
    print(f"Request failed: {e}")

Session Objects for Multiple Requests

with requests.Session() as session:
    session.headers.update({"Authorization": "Bearer token123"})
    r1 = session.get("https://api.example.com/user")
    r2 = session.get("https://api.example.com/posts")