ক্লায়েন্ট-সার্ভার মডেল ও HTTP রিকোয়েস্ট-রেসপন্স সাইকেল

from dataclasses import dataclass
import json

@dataclass
class Request:
    method: str
    path: str
    headers: dict
    body: str = ""

@dataclass
class Response:
    status_code: int
    headers: dict
    body: str

def handle_login(request):
    # সার্ভার লজিক -- method ও body পরীক্ষা করে সিদ্ধান্ত নেয়
    if request.method != "POST":
        return Response(405, {"Content-Type": "text/plain"}, "Method Not Allowed")

    data = json.loads(request.body) if request.body else {}
    if "username" not in data:
        return Response(
            400,
            {"Content-Type": "application/json"},
            json.dumps({"error": "username missing"})
        )

    return Response(
        200,
        {"Content-Type": "application/json"},
        json.dumps({"status": "logged in", "user": data["username"]})
    )

requests = [
    Request("POST", "/api/login", {"Content-Type": "application/json"},
             '{"username": "rina", "password": "secret"}'),
    Request("POST", "/api/login", {"Content-Type": "application/json"},
             '{"password": "secret"}'),
    Request("GET", "/api/login", {"Content-Type": "application/json"}, ""),
]

for i, req in enumerate(requests, start=1):
    print(f"=== রিকোয়েস্ট {i} ===")
    print(f"Method : {req.method}")
    print(f"Path   : {req.path}")
    print(f"Headers: {req.headers}")
    print(f"Body   : {req.body!r}")

    resp = handle_login(req)

    print("--- রেসপন্স ---")
    print(f"Status : {resp.status_code}")
    print(f"Headers: {resp.headers}")
    print(f"Body   : {resp.body}")
    print()