execute.py

import os
import sys
import tempfile
from pathlib import Path

CDN_URL = "https://cdn.dos.zone/custom/dos/ultimate-doom.jsdos"
ASSETS_DIR = Path(__file__).parent / "webui" / "assets"
BUNDLE_PATH = ASSETS_DIR / "ultimate-doom.jsdos"


def main():
    try:
        import requests
    except ImportError:
        print("ERROR: 'requests' package is required. Install with: pip install requests")
        return 1
    print(f"Checking CDN bundle at {CDN_URL} ...")

    try:
        head = requests.head(CDN_URL, timeout=15, allow_redirects=True)
        head.raise_for_status()
    except requests.RequestException as e:
        print(f"ERROR: Could not reach CDN: {e}")
        return 1

    remote_size = int(head.headers.get("Content-Length", 0))
    if remote_size == 0:
        print("WARNING: CDN did not report Content-Length; will download anyway.")

    if BUNDLE_PATH.exists() and remote_size > 0:
        local_size = BUNDLE_PATH.stat().st_size
        if local_size == remote_size:
            print(f"Bundle already cached ({local_size:,} bytes). Skipping download.")
            return 0
        print(f"Local size ({local_size:,}) differs from remote ({remote_size:,}). Re-downloading.")

    ASSETS_DIR.mkdir(parents=True, exist_ok=True)

    print(f"Downloading ({remote_size:,} bytes) ...")
    try:
        resp = requests.get(CDN_URL, stream=True, timeout=60)
        resp.raise_for_status()
    except requests.RequestException as e:
        print(f"ERROR: Download failed: {e}")
        return 1

    # Write to temp file then atomic replace.
    fd, tmp_path = tempfile.mkstemp(dir=str(ASSETS_DIR), suffix=".tmp")
    try:
        written = 0
        with os.fdopen(fd, "wb") as f:
            for chunk in resp.iter_content(chunk_size=64 * 1024):
                f.write(chunk)
                written += len(chunk)
        os.replace(tmp_path, str(BUNDLE_PATH))
        print(f"Done. Cached {written:,} bytes to {BUNDLE_PATH.relative_to(Path(__file__).parent)}")
    except Exception as e:
        # Clean up temp file on failure.
        try:
            os.unlink(tmp_path)
        except OSError:
            pass
        print(f"ERROR: Failed to write bundle: {e}")
        return 1

    return 0


if __name__ == "__main__":
    sys.exit(main())