buggy_server2.py

import hashlib
import random
import time
from http.server import BaseHTTPRequestHandler, HTTPServer


class BuggyHandler(BaseHTTPRequestHandler):
    rnd_states = []
    seed_step = 1024 * 1024
    size = 1024 * 1024 * 1024 + random.randint(0, 1024 * 1024)

    def do_GET(self):
        start = 0
        end = self.size
        if self.headers.get("Range"):
            start, end = self.headers["Range"].split("=")[1].split("-")
            start = int(start) if start else 0
            end = min(self.size, int(end)) if end else self.size

        to_send = max(0, end - start)

        self.send_response(200 if end == self.size else 206)
        self.send_header("Content-Type", "application/octet-stream")
        self.send_header("Content-Length", str(to_send))
        self.send_header("Connection", "close")
        self.end_headers()

        if to_send == 0:
            return

        # Making the life harder.
        time.sleep(random.randint(1, 100) * 0.01)

        seeds_idx, skip = divmod(start, self.seed_step)
        remains = end - start + skip

        while remains:
            data_gen = random.Random()
            data_gen.setstate(self.rnd_states[seeds_idx])
            seeds_idx += 1

            chunk = data_gen.randbytes(min(self.seed_step, remains))
            remains -= len(chunk)

            chunk = chunk[skip:]
            skip = 0

            # Making the life harder.
            oops = random.randint(0, 49) == 0
            if oops and len(chunk) > 64 * 1024:
                chunk = chunk[:random.randrange(64 * 1024, len(chunk))]

            self.wfile.write(chunk)
            if oops:
                break

def run_server():
    host = "127.0.0.1"
    port = 8080

    print("Length of data:", BuggyHandler.size)
    h = hashlib.sha256()
    remains = BuggyHandler.size
    while remains:
        rnd = random.Random()
        BuggyHandler.rnd_states.append(rnd.getstate())
        chunk = rnd.randbytes(min(BuggyHandler.seed_step, remains))
        h.update(chunk)
        remains -= len(chunk)
    print("SHA-256 hash of the data:", h.hexdigest())

    httpd = HTTPServer((host, port), BuggyHandler, bind_and_activate=True)
    httpd.allow_reuse_address = True
    print(f"Starting HTTP server on port {host}:{port}")
    try:
        httpd.serve_forever()
    except KeyboardInterrupt:
        print("\nStopping server...")
        httpd.server_close()


if __name__ == "__main__":
    run_server()