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fix AES-GCM handling #28

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AndyVale wants to merge 1 commit into from
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fix AES-GCM handling #28

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30 changes: 14 additions & 16 deletions src/worker.py
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Original file line number Diff line number Diff line change
Expand Up @@ -40,9 +40,14 @@
import re
import traceback
from urllib.parse import urlparse, parse_qs

from workers import Response
import js
from pyodide.ffi import to_js


def jso(obj):
"""Utility to convert Python types to JS objects (Object.fromEntries for dicts)."""
return to_js(obj, create_pyproxies=False, dict_converter=js.Object.fromEntries)
Comment on lines +48 to +50
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@coderabbitai coderabbitai bot Mar 27, 2026

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🧹 Nitpick | 🔵 Trivial

Nice fix for the Map vs Object issue!

This helper correctly addresses the root cause described in the PR — js.Object.fromEntries ensures Web Crypto APIs receive plain JS Objects instead of Maps.

One small improvement for maintainability: consider adding type hints. Since the function accepts various Python types and returns a JS proxy, something like:

from typing import Any

def jso(obj: Any) -> Any:
    ...

This helps future contributors understand the function's flexibility at a glance. As per coding guidelines, "Review Python code for... proper type hints."

🤖 Prompt for AI Agents 
Verify each finding against the current code and only fix it if needed.

In `@src/worker.py` around lines 48 - 50, Add type hints to the jso helper to
improve readability and follow project guidelines: import typing.Any and
annotate the function signature as def jso(obj: Any) -> Any, keeping the
implementation intact that calls to_js(...,
dict_converter=js.Object.fromEntries). Reference the existing jso function and
the to_js/js.Object.fromEntries usage so the maintainer knows exactly where to
add the import and signature change.


def capture_exception(exc: Exception, req=None, _env=None, where: str = ""):
"""Best-effort exception logging with full traceback and request context."""
Expand Down Expand Up @@ -109,12 +114,9 @@ def _derive_aes_key_bytes(secret: str) -> bytes:

async def _import_aes_key(key_bytes: bytes) -> object:
"""Import raw bytes as a Web Crypto AES-GCM CryptoKey."""
import js
from pyodide.ffi import to_js
key_buf = to_js(key_bytes, create_pyproxies=False)
algo = to_js({"name": "AES-GCM"}, create_pyproxies=False)
usages = to_js(["encrypt", "decrypt"], create_pyproxies=False)
return await js.crypto.subtle.importKey("raw", key_buf, algo, False, usages)
return await js.crypto.subtle.importKey(
"raw", jso(key_bytes), jso({"name": "AES-GCM"}), False, jso(["encrypt", "decrypt"])
)


async def encrypt_aes(plaintext: str, secret: str) -> str:
Expand All @@ -126,13 +128,11 @@ async def encrypt_aes(plaintext: str, secret: str) -> str:
if not plaintext:
return ""
try:
import js
from pyodide.ffi import to_js
key_bytes = _derive_aes_key_bytes(secret)
crypto_key = await _import_aes_key(key_bytes)
iv = bytes(js.crypto.getRandomValues(to_js(bytearray(12))))
algo = to_js({"name": "AES-GCM", "iv": to_js(iv)}, create_pyproxies=False)
data = to_js(plaintext.encode("utf-8"), create_pyproxies=False)
iv = bytes(js.crypto.getRandomValues(jso(bytearray(12))))
algo = jso({"name": "AES-GCM", "iv": jso(iv)})
data = jso(plaintext.encode("utf-8"))
ct_buf = await js.crypto.subtle.encrypt(algo, crypto_key, data)
ct = bytes(js.Uint8Array.new(ct_buf))
return "v1:" + base64.b64encode(iv + ct).decode("ascii")
Expand All @@ -149,8 +149,6 @@ async def decrypt_aes(ciphertext: str, secret: str) -> str:
return ""
if not ciphertext.startswith("v1:"):
return _decrypt_xor(ciphertext, secret)
import js
from pyodide.ffi import to_js
try:
raw = base64.b64decode(ciphertext[3:])
iv, ct = raw[:12], raw[12:]
Expand All @@ -159,8 +157,8 @@ async def decrypt_aes(ciphertext: str, secret: str) -> str:
return "[decryption error]"
key_bytes = _derive_aes_key_bytes(secret)
crypto_key = await _import_aes_key(key_bytes)
algo = to_js({"name": "AES-GCM", "iv": to_js(iv)}, create_pyproxies=False)
data = to_js(ct, create_pyproxies=False)
algo = jso({"name": "AES-GCM", "iv": jso(iv)})
data = jso(ct)
try:
pt_buf = await js.crypto.subtle.decrypt(algo, crypto_key, data)
return bytes(js.Uint8Array.new(pt_buf)).decode("utf-8")
Expand Down