qual: base64url encoding without padding by default

Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>

Author: grencez

pyproject.toml

@@ -8,7 +8,6 @@ authors = [
   { name = "Alex Klinkhamer", email = "about.rendezqueue@grencez.dev" }
 ]
 dependencies = [
-    "sxpb @ git+https://github.com/sxproto/sxpb-py@1a270175d69e58975ba231fa276d27b9d28c00d1",
 ]
 readme = "README.md"
 requires-python = ">=3.9"
@@ -38,6 +37,7 @@ package-dir = "src"
 dev = [
   "pytest",
   "ruff",
+  "sxpb @ git+https://github.com/sxproto/sxpb-py@04fbc53342cb7c7dd75166be955253711966f5e2",
   "ty",
 ]
 

src/rendezqueue/client.py

@@ -89,7 +89,8 @@ def _poll(self) -> None:
                 # Take snapshot of queue to send
                 snapshot_queue = list(self.outgoing_queue)
                 b64_values = [
-                    base64.b64encode(v).decode("ascii") for v in snapshot_queue
+                    base64.urlsafe_b64encode(v).decode("ascii").rstrip("=")
+                    for v in snapshot_queue
                 ]
 
             request_body = {
@@ -171,7 +172,9 @@ def _decode_response(self, msg: Dict[str, Any]) -> Dict[str, Any]:
         return msg
 
     def _b64decode_padded(self, s: str) -> bytes:
+        # Support both regular base64 and base64url by standardizing to base64url alphabet
+        s = s.replace("+", "-").replace("/", "_")
         missing_padding = len(s) % 4
         if missing_padding:
             s += "=" * (4 - missing_padding)
-        return base64.b64decode(s, validate=False)
+        return base64.urlsafe_b64decode(s)

src/rendezqueue/impl.py

@@ -16,6 +16,8 @@ def btoa(s: str) -> str:
 
 def atob(s: str) -> str:
     # URL-safe base64 decoding with padding added
+    # Support both regular base64 and base64url by standardizing to base64url alphabet
+    s = s.replace("+", "-").replace("/", "_")
     missing_padding = len(s) % 4
     if missing_padding:
         s += "=" * (4 - missing_padding)

test/client_test.py

@@ -108,6 +108,13 @@ def test_decode_padding(self):
         decoded = self.client._decode_response(msg)
         self.assertEqual(decoded["values"][0], b"test padding")
 
+    def test_base64url_decoding(self):
+        # Test base64url decoding with missing padding
+        encoded = base64.urlsafe_b64encode(b"ab\xbf\x9c").decode("ascii").rstrip("=")
+        msg = {"values": [encoded], "b64": 1}
+        decoded = self.client._decode_response(msg)
+        self.assertEqual(decoded["values"][0], b"ab\xbf\x9c")
+
     @patch("urllib.request.urlopen")
     def test_defaults(self, mock_urlopen):
         # Initialize client without callbacks