Networking & Protocols

import requests

# GET request - retrieve data
response = requests.get(
    "https://api.example.com/users",
    headers={"Authorization": "Bearer token123"}
)
print(response.status_code)  # 200
print(response.json())       # [{"id": 1, "name": "Alice"}, ...]

# POST request - create data
new_user = {"name": "Bob", "email": "[email protected]"}
response = requests.post(
    "https://api.example.com/users",
    json=new_user,
    headers={"Content-Type": "application/json"}
)
print(response.status_code)  # 201 Created

# PUT request - update entire resource
updated_user = {"name": "Bob Smith", "email": "[email protected]"}
response = requests.put(
    "https://api.example.com/users/2",
    json=updated_user
)

# DELETE request - remove resource
response = requests.delete("https://api.example.com/users/2")
print(response.status_code)  # 204 No Content

import asyncio
import websockets

# WebSocket Server
async def chat_handler(websocket, path):
    """Handle a WebSocket connection for a chat app."""
    print(f"Client connected from {websocket.remote_address}")

    try:
        async for message in websocket:
            # Echo the message back (in a real app, broadcast to all clients)
            print(f"Received: {message}")
            await websocket.send(f"Server echo: {message}")
    except websockets.exceptions.ConnectionClosed:
        print("Client disconnected")

# Start the server
async def main():
    server = await websockets.serve(chat_handler, "localhost", 8765)
    print("WebSocket server running on ws://localhost:8765")
    await server.wait_closed()

asyncio.run(main())

# ---- WebSocket Client ----
async def client():
    async with websockets.connect("ws://localhost:8765") as ws:
        await ws.send("Hello, server!")
        response = await ws.recv()
        print(response)  # "Server echo: Hello, server!"

import socket
import dns.resolver  # pip install dnspython

# Simple DNS resolution using socket
ip_address = socket.gethostbyname("www.google.com")
print(f"Google IP: {ip_address}")

# Detailed DNS query using dnspython
def lookup_dns(domain, record_type="A"):
    """Query DNS records for a domain."""
    try:
        answers = dns.resolver.resolve(domain, record_type)
        print(f"\n{record_type} records for {domain}:")
        for rdata in answers:
            print(f"  {rdata}")
        print(f"  TTL: {answers.rrset.ttl} seconds")
    except dns.resolver.NXDOMAIN:
        print(f"Domain {domain} does not exist")

# Look up different record types
lookup_dns("google.com", "A")      # IPv4 address
lookup_dns("google.com", "MX")     # Mail servers
lookup_dns("google.com", "NS")     # Name servers
lookup_dns("google.com", "TXT")    # TXT records

# Output:
# A records for google.com:
#   142.250.80.46
#   TTL: 300 seconds