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"""HackThisSite Programming 4 manual-reading assistant.
Modes:
offline: read a saved XML;
live: GET a fresh XML into scratch using HTS_COOKIE.
The script performs only fetch/decompress/parse/render. It never POSTs and never
writes the cookie. It creates five complete colour layers in answer order:
01-blue.png, 02-green.png, 03-red.png, 04-yellow.png, 05-white.png.
Each image keeps the original 1000x1000 canvas and all geometry for that colour.
"""
from __future__ import annotations
import argparse
import bz2
import hashlib
import json
import math
import os
import re
import sys
import time
import xml.etree.ElementTree as ET
from pathlib import Path
from urllib.request import Request, urlopen
from PIL import Image, ImageDraw
BASE = "https://www.hackthissite.org"
UA = ("Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 "
"Chrome/131.0.0.0 Safari/537.36")
ORDER = ("blue", "green", "red", "yellow", "white")
RGB = {
"blue": (0, 0, 255),
"green": (0, 255, 0),
"red": (255, 0, 0),
"yellow": (255, 255, 0),
"white": (255, 255, 255),
}
CANVAS = 1000
SCALE = 4
WIDTH = 2 * SCALE
def fetch_url(url: str, headers: dict[str, str]):
request = Request(url, headers=headers)
with urlopen(request, timeout=20) as response:
return response.read(), dict(response.headers)
def fetch_live(cookie: str, out: Path):
"""Fetch and decompress one instance; cookie is kept only in memory."""
out.mkdir(parents=True, exist_ok=True)
headers = {
"User-Agent": UA,
"Cookie": cookie,
"Referer": BASE + "/missions/programming/",
}
page_bytes, _ = fetch_url(BASE + "/missions/prog/4/", headers)
page_text = page_bytes.decode("utf-8", errors="replace")
links = re.findall(
r'href=["\']([^"\']*prog/4/(?:XML|xml)[^"\']*)',
page_text,
flags=re.I,
)
url = (
BASE + links[0] if links and links[0].startswith("/")
else links[0] if links else BASE + "/missions/prog/4/XML/"
)
if not url.endswith("/"):
url += "/"
packed, response_headers = fetch_url(url, headers)
if packed[:3] != b"BZh":
raise RuntimeError(
"XML endpoint did not return bzip2; "
f"bytes={len(packed)} content_type={response_headers.get('Content-Type')}"
)
raw = bz2.decompress(packed)
xml = out / "instance.xml"
(out / "instance.xml.bz2").write_bytes(packed)
xml.write_bytes(raw)
return xml, url, packed, raw
def local(tag):
return tag.rsplit("}", 1)[-1]
def load_xml(path: Path):
raw = path.read_bytes()
if raw.startswith(b"BZh"):
raw = bz2.decompress(raw)
return ET.fromstring(raw)
def draw_colour(xml: Path, colour: str, dst: Path):
"""Render one complete colour layer on the original 1000x1000 canvas."""
root = load_xml(xml)
image = Image.new("RGB", (CANVAS * SCALE, CANVAS * SCALE), "black")
draw = ImageDraw.Draw(image)
count = 0
for element in root:
kind = local(element.tag)
data = {local(x.tag): (x.text or "").strip() for x in element}
current = (data.get("Color") or "white").lower()
if current != colour:
continue
count += 1
ink = RGB[colour]
if kind == "Line":
x0 = float(data["XStart"]) * SCALE
y0 = (CANVAS - float(data["YStart"])) * SCALE
x1 = float(data["XEnd"]) * SCALE
y1 = (CANVAS - float(data["YEnd"])) * SCALE
draw.line((x0, y0, x1, y1), fill=ink, width=WIDTH)
elif kind == "Arc":
cx = float(data["XCenter"])
cy = float(data["YCenter"])
radius = float(data["Radius"])
start = float(data["ArcStart"])
extend = float(data["ArcExtend"])
box = (
(cx - radius) * SCALE,
(CANVAS - (cy + radius)) * SCALE,
(cx + radius) * SCALE,
(CANVAS - (cy - radius)) * SCALE,
)
draw.arc(box, -(start + extend), -start, fill=ink, width=WIDTH)
image.resize((CANVAS, CANVAS), Image.Resampling.LANCZOS).save(dst)
return count
def render(xml: Path, out: Path):
out.mkdir(parents=True, exist_ok=True)
counts = {}
files = {}
for index, colour in enumerate(ORDER, 1):
dst = out / f"{index:02d}-{colour}.png"
counts[colour] = draw_colour(xml, colour, dst)
files[colour] = str(dst)
return counts, files
def main():
ap = argparse.ArgumentParser()
src = ap.add_mutually_exclusive_group(required=True)
src.add_argument("--xml", type=Path, help="use a saved XML; no network")
src.add_argument("--bz2", type=Path, help="use a saved bzip2 XML; decompress locally")
src.add_argument("--live", action="store_true", help="fetch one fresh XML")
ap.add_argument("--cookie", default=os.environ.get("HTS_COOKIE"),
help="session cookie for --live; never written")
ap.add_argument("--out", type=Path, default=None,
help="output directory; defaults to Hermes scratch")
args = ap.parse_args()
started = time.monotonic()
if args.live:
if not args.cookie:
raise SystemExit("--live requires HTS_COOKIE or --cookie")
out = args.out or Path("hts4-manual-" + str(int(time.time())))
xml, url, packed, raw = fetch_live(args.cookie, out)
else:
out = args.out or Path("hts4-manual-offline")
out.mkdir(parents=True, exist_ok=True)
if args.bz2:
packed = args.bz2.read_bytes()
if packed[:3] != b"BZh":
raise SystemExit(f"not a bzip2 file: {args.bz2}")
raw = bz2.decompress(packed)
xml = out / "instance.xml"
xml.write_bytes(raw)
url = "offline-bz2"
else:
xml = args.xml.resolve()
url, packed, raw = "offline", b"", xml.read_bytes()
counts, files = render(xml, out / "colours")
result = {
"xml": str(xml),
"url": url,
"xml_sha256": hashlib.sha256(raw).hexdigest(),
"bz2_sha256": hashlib.sha256(packed).hexdigest() if packed else None,
"out": str(out),
"colour_dir": str(out / "colours"),
"files": files,
"counts": counts,
"elapsed_s": round(time.monotonic() - started, 3),
"posted": False,
}
(out / "result.json").write_text(
json.dumps(result, indent=2), encoding="utf-8"
)
print(json.dumps(result, indent=2))
print("Read montages in order: " + ",".join(ORDER))
if __name__ == "__main__":
main()
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