Networking (tarmoq)

Python past darajali (low-level) va yuqori darajali (high-level) tarmoq (networking) modullarini taqdim etadi.

• Past daraja (low-level): TCP/UDP mijoz (client) va serverlar uchun socket
• Yuqori daraja (high-level): urllib, http.client, smtplib, imaplib, ftplib va boshqalar

Avval socket bilan asoslarni tushunib oling, keyin production ilovalar uchun yuqori darajali kutubxonalardan foydalaning.

Socket nima?

Socket — bu dasturlar orasidagi ikki tomonlama aloqa (two-way communication) uchun tugun (endpoint). Socket'lar bir xil kompyuterda ishlayotgan process'lar orasida ham, tarmoq orqali boshqa kompyuterlarda ham ishlashi mumkin.

Socket moduli

Socket yaratish:

socket.socket(family=AF_INET, type=SOCK_STREAM)

• AF_INET IPv4 uchun
• SOCK_STREAM TCP uchun
• SOCK_DGRAM UDP uchun

SOCK_STREAM (TCP) ishonchli va tartibli (ordered). SOCK_DGRAM (UDP) tezroq, lekin yetib borishni kafolatlamaydi.

Server socket metodlari

Mijoz (client) socket metodlari

Umumiy socket metodlari

Oddiy TCP server

Bu minimal server bitta mijoz (client) ulanishini qabul qiladi, bir marta javob yuboradi va chiqadi.

# non-runnable: requires external environment/setup
import socket

HOST = "127.0.0.1"
PORT = 12345

with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
    s.bind((HOST, PORT))
    s.listen()
    print(f"Server listening on {HOST}:{PORT}")

    conn, addr = s.accept()
    with conn:
        print("Connected by", addr)
        conn.sendall(b"Thank you for connecting")

Oddiy TCP mijoz (client)

# non-runnable: requires external environment/setup
import socket

HOST = "127.0.0.1"
PORT = 12345

with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
    s.settimeout(5)  # soniya
    s.connect((HOST, PORT))
    data = s.recv(1024)

print(data.decode("utf-8"))

Avval server'ni ishga tushiring, keyin boshqa terminal'dan mijozni (client) ishga tushiring.

Python'dagi keng tarqalgan internet modullari

Production tizimlarda imkon qadar yuqori darajali kutubxonalarni tanlang va doim timeout qo'shing.

Ko'p uchraydigan xatolar

• ConnectionRefusedError: server ishlamayapti yoki host/port noto'g'ri.
• Mijoz (client) recv()da osilib qoladi: timeout yo'q va server data yubormaydi.
• OSError: [Errno 98] Address already in use: oldingi process portni band qilgan.
• str va bytesni aralashtirish: socket byte yuboradi/qabul qiladi, shuning uchun encode/decode ni aniq qiling.