chuanqi/cq2_sdk/scripts/decode_dat.py

"""Decode the .dat launch config (session 755, 62 bytes) + urlCreator.jsc strings.
The .dat is likely the launch-parameter template cq.exe consumes."""
import gzip
import json
from pathlib import Path

import brotli


def decode_response_bytes(path: Path) -> bytes:
    raw = path.read_bytes()
    idx = raw.find(b"\r\n\r\n")
    head = raw[:idx].decode("latin1")
    body = raw[idx + 4 :]
    enc = "br" if "Content-Encoding: br" in head else ("gzip" if "gzip" in head else "")
    chunked = "chunked" in head
    if chunked:
        out = b""
        rest = body
        while rest:
            le = rest.find(b"\r\n")
            if le < 0:
                break
            try:
                sz = int(rest[:le].split(b";")[0], 16)
            except ValueError:
                break
            if sz == 0:
                break
            out += rest[le + 2 : le + 2 + sz]
            rest = rest[le + 2 + sz + 2 :]
        body = out
    if enc == "br":
        body = brotli.decompress(body)
    elif enc == "gzip":
        body = gzip.decompress(body)
    return body


raw_dir = Path(r"C:\Users\ADMINI~1\AppData\Local\Temp\opencode\saz_dec\raw")

# 1. the .dat file (session 755)
print("=== session 755: 20260804_cq.dat (62B) ===")
dat = decode_response_bytes(raw_dir / "755_s.txt")
print(f"  raw hex: {dat.hex()}")
print(f"  raw repr: {dat!r}")
try:
    print(f"  as text: {dat.decode('utf-8')}")
    j = json.loads(dat)
    print(f"  as json: {json.dumps(j, indent=2)}")
except Exception:
    pass

# try xxtea with the known key
print()
print("=== try XXTEA-decrypt the .dat ===")
import struct
import sys
sys.path.insert(0, ".")
from cq2_sdk.utils.encoding import encode6bit  # noqa

# maybe it's encoded with Encode6BitBuf
try:
    dec = encode6bit(dat)
    print(f"  encode6bit: {dec[:80]}")
except Exception as e:
    print(f"  encode6bit err: {e}")

# simple XOR/reverse checks
print(f"  reversed hex: {dat[::-1].hex()}")
print(f"  as int32s: {list(struct.unpack('<' + 'i' * (len(dat) // 4), dat[:len(dat) // 4 * 4]))}")

# 2. urlCreator.jsc strings
print()
print("=== urlCreator.jsc extractable strings ===")
jsc = Path(r"C:\Users\ADMINI~1\AppData\Local\Temp\opencode\asar2\src\libs\urlCreator.jsc")
if jsc.exists():
    data = jsc.read_bytes()
    import re

    for m in re.finditer(rb"[\x20-\x7e]{4,80}", data):
        print(f"  {m.group().decode('ascii')}")
else:
    print("  urlCreator.jsc missing")